WOT Tuning

[XfireZ51]

With the recent results I've gotten at the track and on the dyno, I have started looking for ways I can optimize tune for WOT. I heard about doing "plug cuts" before but never took the time. This time I did. Very revealing.
Looks like its running "a bit" rich and that I have some fuel to take out. Next step is hooking up my ZT-2 at the collector. My suspicion is that the WB at the dyno is on the lean side because its at the tailpipe. Using my WB at the collector should give me a more accurate reading. Attached
is a pic of an NGK BKR7E plug on the left and an AC Delco 41-602 on the right.

[Paul Workman]

With the recent results I've gotten at the track and on the dyno, I have started looking for ways I can optimize tune for WOT. I heard about doing "plug cuts" before but never took the time. This time I did. Very revealing.
Looks like its running "a bit" rich and that I have some fuel to take out. Next step is hooking up my ZT-2 at the collector. My suspicion is that the WB at the dyno is on the lean side because its at the tailpipe. Using my WB at the collector should give me a more accurate reading. Attached
is a pic of an NGK BKR7E plug on the left and an AC Delco 41-602 on the right.

Interesting. I've never cut plugs before, but am very familiar w/ the concept of reading plugs. So...a Q for U:

Were either of those plugs pulled immediately after a WOT run, or was there a period of normal (closed loop) fueling and/or a shut-down and cool down and a restart? Point is, plug reading to determine fuel rich/lean, etc, is pretty quickly compromised by conditions outside those being tested - hence my question.;)

P.

[XfireZ51]

Paul,

The answer is that neither were pulled immediately after a run and then shutdown. However, as you look at the porcelain, there are 3 regions. Closest to the tip being idle, mid-section indicates cruise, and the bottom is WOT and therefore the need for the plug cut. Ideally, the bottom should have a wispy tan look to it. I may try to borrow my wife's tool for examining childrens ears. That supposed to work too but I had these plugs laying around and thought I'd give it a shot. After the track, I decided to try a plug one step hotter but I still need to pull fuel out of the WOT zone of the VE MAP.

[Paul Workman]

Paul,

The answer is that neither were pulled immediately after a run and then shutdown. However, as you look at the porcelain, there are 3 regions. Closest to the tip being idle, mid-section indicates cruise, and the bottom is WOT and therefore the need for the plug cut. Ideally, the bottom should have a wispy tan look to it. I may try to borrow my wife's tool for examining childrens ears. That supposed to work too but I had these plugs laying around and thought I'd give it a shot. After the track, I decided to try a plug one step hotter but I still need to pull fuel out of the WOT zone of the VE MAP.

I use an 8x eye loupe, but I'm too cheep to start cutting my platinum plugs, I guess ;)

Anywayz, mebby ya need to have a spare plug or two and shut 'er down at the trap and coast into the turnout area. That way the results won't be compromised.

A quick read some may find interesting::)

http://www.dragstuff.com/techarticles/reading-spark-plugs.html

P.

[XfireZ51]

I use an 8x eye loupe, but I'm too cheep to start cutting my platinum plugs, I guess ;)

Anywayz, mebby ya need to have a spare plug or two and shut 'er down at the trap and coast into the turnout area. That way the results won't be compromised.

A quick read some may find interesting::)

http://www.dragstuff.com/techarticles/reading-spark-plugs.html

P.

Paul,

As much as I would like to do that, I am more concerned with removing and tightening plugs on hot aluminum cylinder heads. Very few places where I could go thru that cycle around here so a certain amount of contamination is unavoidable.
BTW, that was one of the articles I read on plug reading. One of the reasons I got the NGK BKR plugs is that they were less expensive but provided the heat range I was looking to test. Once satisfied that I have the right heat range, I can then move up to a Platinum or Iridium equivalent.

[Bob G]

Thats what anti sieze is for I use it on the pro stocks every pass
Bob

[XfireZ51]

Thats what anti sieze is for I use it on the pro stocks every pass
Bob


Thanks Bob. I do use anti-seize when I install the plugs.

[Starman]

Guys, as I recall the LT-5 is programmed for a 12:1 fuel/air ratio with the secondary injectors on. It will be faster if you lean it out (ideal stochiometric ratio for gas is 14:1), but it is programmed rich to protect against detonation. Let's face it, the 90-92 cars have 2nd generation ECMs and only read every 25 RPM. With Speed Density control and batch fired injectors there is not much to work with here. You can detonate the hell out of the car without it responding enough to prevent it, just on a bad tank of gas.

The 93 up cars have the P8 ECM that read every RPM. I've often thought that there would be more driveability there but have not found anyone that has made the change.

[Paul Workman]

Guys, as I recall the LT-5 is programmed for a 12:1 fuel/air ratio with the secondary injectors on. It will be faster if you lean it out (ideal stochiometric ratio for gas is 14:1), but it is programmed rich to protect against detonation. Let's face it, the 90-92 cars have 2nd generation ECMs and only read every 25 RPM. With Speed Density control and batch fired injectors there is not much to work with here. You can detonate the hell out of the car without it responding enough to prevent it, just on a bad tank of gas.

The 93 up cars have the P8 ECM that read every RPM. I've often thought that there would be more driveability there but have not found anyone that has made the change.

Not to pick a nit, but I double checked and the LT5 injectors (according to my sources) are sequentially fired, unlike the L98. That notion is supported by the fact there are individual (ECM) injector control leads on the Zs - not "ganged" (L98s, etc) for what it's worth.;)

P.

[XfireZ51]

Here's the latest on my playing around with spark plug heat range.

First .jpeg shows ground strap heat range indication. Yoou can see that the color changes near or at the gs bend.

Second .jpeg shows the fire ring at base of porcelain. The plugs are (left to right),
BKR6E, AC 41-602, BKR7E, TR55XI. Looks like there's more fuel to take out at top end but I'll need to monitor KR and AFR using my WB. However, it tends to confirm that my suspicion is that the WB, at the tailpipe, used by the dyno operator is reporting lean.

[mrand]

Guys, as I recall the LT-5 is programmed for a 12:1 fuel/air ratio with the secondary injectors on. It will be faster if you lean it out (ideal stochiometric ratio for gas is 14:1), but it is programmed rich to protect against detonation. Let's face it, the 90-92 cars have 2nd generation ECMs and only read every 25 RPM. With Speed Density control and batch fired injectors there is not much to work with here. You can detonate the hell out of the car without it responding enough to prevent it, just on a bad tank of gas.

The 93 up cars have the P8 ECM that read every RPM. I've often thought that there would be more driveability there but have not found anyone that has made the change.
I'm sorry to say that, regarding LT5 applications, there isn't much correct in this quoted post.

"Ideal stochiometric ratio" describes a chemically balanced mixture - it has nothing to do with best performance. Leaning out the AFR of a performance engine at WOT to anything approaching 14:1 is a recipe for disaster.
Has has been pointed out, the LT5 injectors are not batched fired.
The computer runs plenty fast to respond to rpm changes. The post makes it sound like the computer sits around and once every 25 rpms does something. That isn't correct. And while a bad tank of gas could cause a little detonation, there is a knock sensor which will prevent "detonating the hell out of the car." And really - do people get "bad" tanks of gas any more? Lastly, the computer used in 1993 was not noticeably different than the one used in previous years.Marc

[Tyler Townsley]

Buy a WB with recording capability and have it plumed into the collector. I am all for reading plugs but having a actual track picture would pay for itself in the end. Marc is right, 14.7 is not anywhere near your target AFR for load based tuning. Not sure what Marc uses as his baseline for WOT but it would be a good start. I would think money spent on suspension improvements would have a better return than trying to find additional HP through calibration changes.

Tyler

[tpepmeie]

I would think money spent on suspension improvements would have a better return than trying to find additional HP through calibration changes.

Tyler

Tyler, you keep that logic up and we'll have to award you a Beacon of Reality award. Can we do that on the forum? :razz:

Seriously, Marc has spoken the truth also. There has been this urban legend posted before about the mysterious "P8" ECM in 93+ cars. It isn't true, at lease to the best of my knowledge...still got the good ole P4.

Todd

[XfireZ51]

Buy a WB with recording capability and have it plumed into the collector. I am all for reading plugs but having a actual track picture would pay for itself in the end. Marc is right, 14.7 is not anywhere near your target AFR for load based tuning. Not sure what Marc uses as his baseline for WOT but it would be a good start. I would think money spent on suspension improvements would have a better return than trying to find additional HP through calibration changes.

Tyler

Not certain if this was directed to me or someone else. I think I previously stated that I do have a ZT-2. Used it for 2 years on my old 84. Haven't installed it yet on the ZR deciding how to route it into the cabin. As for finding additional HP from calibration changes, so far with a change of plug heat range ($1.50/plug) and modifying both SA and VE tables(FREE) where it counts, I've been able to pick up about 2- 2.5 mph in trap speed. IMO, pretty good bang for the buck and I don't think I'm done yet. I'd agree that tires should be on the short list.

[Tyler Townsley]

Not certain if this was directed to me or someone else. I think I previously stated that I do have a ZT-2. Used it for 2 years on my old 84. Haven't installed it yet on the ZR deciding how to route it into the cabin. As for finding additional HP from calibration changes, so far with a change of plug heat range ($1.50/plug) and modifying both SA and VE tables(FREE) where it counts, I've been able to pick up about 2- 2.5 mph in trap speed. IMO, pretty good bang for the buck and I don't think I'm done yet. I'd agree that tires should be on the short list.

Kind of both. Repairing a broke LT 5 can be expensive. There is a lot of collective wisdom on this forum that hopefully can help. I do not know your knowledge level on the calibration tables so I am urging caution. If I were to race a ZR-1 the first thing I would address is the radiator bypass and how it functions. In stock configuration this system starts routing water around the radiator at 5200 rpm and by 5800 you have almost no water being cooled unless you slow the revs back down, leaning the motor only increases the likelyhood of blowing a head gasket in this situation. The fix is simple but does call for a heavy duty radiator and cutting the thermostat pressure spring and blocking the bypass.

It is obvious you are comfortable with data monitoring so there is no reason to fly blind. Take the laptop and record a session then look at temps and rpms then look at the AFRs from your WB O2 to see just what fueling is doing throughout the run. What happened to spark? As previously stated the computer will pull timing out and you will never notice without going back over the data. Oh yeah start the session with enough fuel so you will have at least 1/4 tank at the end of the session. The dual pumps suck a lot of fuel and it does not take much to lean out the motor when a turn or stop pulls fuel away from the pickup.

Tyler

[XfireZ51]

... If I were to race a ZR-1 the first thing I would address is the radiator bypass and how it functions. In stock configuration this system starts routing water around the radiator at 5200 rpm and by 5800 you have almost no water being cooled unless you slow the revs back down, leaning the motor only increases the likelyhood of blowing a head gasket in this situation. The fix is simple but does call for a heavy duty radiator and cutting the thermostat pressure spring and blocking the bypass.

Interesting. Thanks for that bit of advice.

It is obvious you are comfortable with data monitoring so there is no reason to fly blind. Take the laptop and record a session then look at temps and rpms then look at the AFRs from your WB O2 to see just what fueling is doing throughout the run. What happened to spark? As previously stated the computer will pull timing out and you will never notice without going back over the data. Oh yeah start the session with enough fuel so you will have at least 1/4 tank at the end of the session. The dual pumps suck a lot of fuel and it does not take much to lean out the motor when a turn or stop pulls fuel away from the pickup.

Tyler

Last year I datalogged a number of runs at the track. That led me to re-curve spark avoiding the knock retard. Trap speed went from 111 to 115mph.
The most recent changes I made were based on datalogs from my dyno runs a few weeks before. Having done some plug cuts, I began to suspect that the WB used at the dyno may have been reading lean although the dyno charts showed a pretty
steady 12.8 - 12.9 AFR up thru 7000rpm.
Hoping to go to track one last time this weekend. Back to your point however, if I lean it out any more, I will be datalogging looking for any knock. I'll keep you posted.

[Tyler Townsley]

Interesting. Thanks for that bit of advice.



Last year I datalogged a number of runs at the track. That led me to re-curve spark avoiding the knock retard. Trap speed went from 111 to 115mph.
The most recent changes I made were based on datalogs from my dyno runs a few weeks before. Having done some plug cuts, I began to suspect that the WB used at the dyno may have been reading lean although the dyno charts showed a pretty
steady 12.8 - 12.9 AFR up thru 7000rpm.
Hoping to go to track one last time this weekend. Back to your point however, if I lean it out any more, I will be datalogging looking for any knock. I'll keep you posted.

Here is a picture of which spring to cut. When you cut the thermo like this it is always open for water flow as long as the bypass does not open to pull the water around the radiator which is why I put a 1 in plug in the hose to block the bypass. Do not do this unless you have upgraded the stock radiator.

http://deliquescence.net/~tyler/misc/Thermo.jpg

Another point to consider is that the best HP in a LT 5 is made when the water temp is between 160-165 deg. This was tested some years ago by a tuner and I asked Graham B directly and he agreed that the test was accurate. He also made the point that OEM water temp was a compromise between emissions and power with emission winning the day. If you go back and look at your earlier data runs I would be interested in what you see when you compare rpms to water temp. IE what happens when you hold a rpm over 5800 for a period on time.

Tyler

[XfireZ51]

Tyler,

Thank you for that. I will review my datalogs altho I think the main issue is maintaining a 160F temp before a run. You know you just sit there waiting to get up to the line. :handshak:

[Jeffvette]

If I were to race a ZR-1 the first thing I would address is the radiator bypass and how it functions. In stock configuration this system starts routing water around the radiator at 5200 rpm and by 5800 you have almost no water being cooled unless you slow the revs back down, leaning the motor only increases the likelyhood of blowing a head gasket in this situation. The fix is simple but does call for a heavy duty radiator and cutting the thermostat pressure spring and blocking the bypass.


Tyler,I have no problems running my car at the track with a Ron Davis and a 170 Therm. I double stinted the car with Dwight at the track this past summer and the coolant temps were never a problem. The oil temp was a different story though.

[Tyler Townsley]

Tyler,I have no problems running my car at the track with a Ron Davis and a 170 Therm. I double stinted the car with Dwight at the track this past summer and the coolant temps were never a problem. The oil temp was a different story though.

The bypass works by pressure. The stock radiator has a low (restriction)flow rating and once the water pressure gets to a certain point (5200 rpm) the spring on the thermo begins to open and water goes around the radiator. The Ron Davis has a higher flow rate (less restriction) which raises the flow needed to open the bypass spring. With the cut thermo I could run 160 deg-165 deg with A/C and outside temps of 95+ as long as I was moving.

Lane Goldstein (Fastlane) used a switch in the cockpit to turn on his fans with engine off to cool down his motor between runs. You can do the same thing by turning off the motor but leave the ignition on and turning on the A/C both fans should come on.

Tyler

[Tyler Townsley]

Another little know reality is the worthlessness of the oil cooler system. There is a thermostat like device that prevents any meaningfull oil being circulated through the cooler until the oil gets to over 240+ deg. by then it is really too late to help. So if you are looking to address cooling the oil you have to do something about this 'thermostat' first.

Tyler

[XfireZ51]

Another little know reality is the worthlessness of the oil cooler system. There is a thermostat like device that prevents any meaningfull oil being circulated through the cooler until the oil gets to over 240+ deg. by then it is really too late to help. So if you are looking to address cooling the oil you have to do something about this 'thermostat' first.

Tyler


Tyler,

Please keep those little nuggets coming. =D>

[jonszr1]

how would one change the opening temp of the thermastate (oil)

[Jerry#397]

Tyler,

What if the oil thermostate was removed, would that be too much cooling? As prviouly asked how can the opening temperature be changed?

Thanks,
Jerry
93 White ZR1

[Tyler Townsley]

If you remove the water t stat the water will not be in the radiator long enough to cool thats why you cut the spring and leave it in the system. The only down side is that when the outside temp is below about 65 deg the system runs so cool that it never goes into closed loop. Lane kept a piece of cardboard to block the radiator when it was too cold.

I know of no one that has removed the 'oil temperature control valve'. If you look in the service manual 6A2-37 at the breakout for the oil filter housing you can see its location. I have a email to Geoff about where get different value valves. It looks to me that one should be able to replace it without too much trouble.

Tyler

[Tyler Townsley]

Per Geoff Jeal ex Lotus calibrations engineer for the LT 5 engine.

Quote

As far as I know there is no alternative wax capsule for this application, you can however remove the wax stat and jack the shuttle valve open. This is how all of the dyno engines were run during development.

Unquote.

Tyler

[Jerry#397]

Tyler,

Thanks for posting the reply from Geoff. Any thoughts on what the oil temp would be if the valve was open all the time. Past posts stated that we don't have a problem with oil temp unless it's 300F, that temp troubles me. I have a Ron Davis Rad. with a 180F thermo., when doing track events at both Portland and Thunder Hill in Northern Ca. my oil temp will go to 240-250F when the car is being pushed, I back off when I see 250F. I still would like the oil cooler in the loop at all times. Am I being too conservative?

Thanks again,
Jerry

[Tyler Townsley]

Tyler,

Thanks for posting the reply from Geoff. Any thoughts on what the oil temp would be if the valve was open all the time. Past posts stated that we don't have a problem with oil temp unless it's 300F, that temp troubles me. I have a Ron Davis Rad. with a 180F thermo., when doing track events at both Portland and Thunder Hill in Northern Ca. my oil temp will go to 240-250F when the car is being pushed, I back off when I see 250F. I still would like the oil cooler in the loop at all times. Am I being too conservative?

Thanks again,
Jerry

Do not know anyone who has done the mod but if they were doing it on the dyno motors it must have helped stabilize the temp where the wanted it to be. If your oil is going that high your water must be really hot. Not sure what the stock oil cooling system would do after doing the above but if I went to the trouble to mod it as above I would add a cooler rather than use the stock setup unless you do the bypass mod above. In stock form the water temps are still high and since the oil cooling is so close to the radiator I would be concerned that it is not getting as cool as needed.

Tyler

[Jeffvette]

Another little know reality is the worthlessness of the oil cooler system. There is a thermostat like device that prevents any meaningfull oil being circulated through the cooler until the oil gets to over 240+ deg. by then it is really too late to help. So if you are looking to address cooling the oil you have to do something about this 'thermostat' first.

Tyler

Best solution then would be to eliminate the thermostat. I've done that in the race car, but it does not see much cold temp operation unless it's a nice day and i take it out on the streets to cycle everything. But I let it get real hot by cutting off the cooling fans.

[Aurora40]

Another little know reality is the worthlessness of the oil cooler system. There is a thermostat like device that prevents any meaningfull oil being circulated through the cooler until the oil gets to over 240+ deg. by then it is really too late to help. So if you are looking to address cooling the oil you have to do something about this 'thermostat' first.

Tyler
So I have a question? In the winter when air cooling is at its max, the temp should hover around where the thermostat device opens, right? My car in the winter will generally have an oil temp around 180-185F in street driving. I assumed from that that the oil thermostat begins circulating oil at that point? Am I thinking about it wrong?

[Jerry#397]

What is the purpose of the Oil thermo., could it be for those folks in the mid west and eastern states that have those misable winters? Most folks that have a car that is driven hard install "oil coolers", yet they don't have thermostats, so why is there one on the ZR1?

Will be inspecting my cooling system thermostat this week as I don't believe I should be seeing high temps with the RD radiator no matter how hard the car is driven.

Tyler keep posting those "nuggets" of info.

Thanks,
Jerry

[Tyler Townsley]

What is the purpose of the Oil thermo., could it be for those folks in the mid west and eastern states that have those misable winters? Most folks that have a car that is driven hard install "oil coolers", yet they don't have thermostats, so why is there one on the ZR1?

Thanks,
Jerry

According to Geoff the oil cooler setup was kept to help HEAT the oil in cold climates. When they did cold weather testing the proxmity of the cooler to the radiator and the minimal flow helped the car come up to temp faster thus pass the emission testing. With the high thermo opening it was not really designed as a functional oil cooler.

Tyler

[Jerry#397]

Tyler,

Thanks for the reply. I am still confused on the water bypass around the rad.; if the spring is cut why would you have to plug the bypass if the thermostat is what sends the water thru the bypass?

Jerry

[Jerry#397]

Jeff,

Where did you get a 170F thermostat, I find only 180F and of course the $100plus 160F?

Jerry

[Tyler Townsley]

Tyler,

Thanks for the reply. I am still confused on the water bypass around the rad.; if the spring is cut why would you have to plug the bypass if the thermostat is what sends the water thru the bypass?

Jerry

I ran mine both ways. I started without pluging the bypass then ran it with a plug to see if there would be any difference. I did not notice any difference but left it in to make sure there was no hot water leakage around the radiator.

Tyler

[jonszr1]

Jeff,

Where did you get a 170F thermostat, I find only 180F and of course the $100plus 160F?

Jerryrandy woods he also sellls the under drive pullies . he also has a 165 therm that lets our cars run right at 180 . i got that one and love it . the 160 doesnt let the car go into closed loop.hes under specilized racing products . hope this helps

[Jerry#397]

John,
Do you have a web site address for Randy Woods?

Tyler,

If I cut the thermostat spring as indicated in the picture you posted will it allow for bypassing the Rad. when it's cold? I think I understand how it works at high RPM and thus cutting the spring will get rid of that problem but what about warm up, the water needs to go somewhere when the thermo is in the closed position?

Jerry

[jonszr1]

go on the links page on the registry and find specialized racing products click that and your home :cheers:

[Tyler Townsley]

John,

If I cut the thermostat spring as indicated in the picture you posted will it allow for bypassing the Rad. when it's cold? I think I understand how it works at high RPM and thus cutting the spring will get rid of that problem but what about warm up, the water needs to go somewhere when the thermo is in the closed position?

Jerry

Cutting the heavy spring opens the thermo all the time as you are cutting the spring that opens the water flow as the water warms up. IE In the stock configuration when cold the bypass is opened by pressure because the main water route is plugged. As the water flows down the bypass it warms the thermo and it opens to allow flow through the radiator. This drop in pressure closes the bypass and forces water through the radiator until it is opened by pressure brought about by the increased rpms. I also think this design increases the failure rate of the water pumps.

Tyler

[Jerry#397]

Tyler,

If I read your reply correctly it seems to me that one could "plug" the bypass line and remove the thermostat?

Thanks,
Jerry

[Tyler Townsley]

Tyler,

If I read your reply correctly it seems to me that one could "plug" the bypass line and remove the thermostat?

Thanks,
Jerry

Yes, but.

http://deliquescence.net/~tyler/misc/zr1waterflow.jpg

As I said earlier Lane tried this on his 90 at one point and found the water did not cool because it flows through the radiator too quickly to cool the water.

A little more discussion. Lotus speced the LT 5 pump at 25 gpm flow per 1000 rpm. The stock radiator was not reliable over about 100+_ gpm so the bypass was developed to avoid having to source another radiator. GM felt most owners would not operate the motor over 5500 rpm for any length of time so there would not be threat to any long term operations.

Once you start competing with the car you find you spend a lot of time over 5k which will stress the cooling system but the above must be taken in consideration when makeing any changes.

Tyler

[Jerry#397]

Tyler,

Talked with Randy Woods today about his thermostats and the testing that he has done, VERY interesting. I purchased a 165F heavy duty thermostat from him. He stated that he recommends the 165F as it is the best of both worlds (160F vs 170F) and that the 165F heavy duty is built to his specs after much testing; it begins to open at 165F and is fully open at 180F. He went on to say that his fans are set to "both" kick on at 190F and shut off at 180F.

We talked about the "bypass" and he validated what you and Fast Lane had said about keeping some water flow thru the bypass.

Hopefully he will post some of his testing results.

Again want to thank you for sharing all the "nuggets" of info on the cooling system and the oil cooling system.

Jerry

[tomtom72]

Tyler, I would like to add my thanks also for your sharing the light about the cooling systems, both water & oil. :thumbsup:

At 25 gpm flow/1k rpms, would that be a constant multiplier? So that at 7k rpms the flow is 175 gpm?......in theory only, minus the reducing effects of pump cavitation on flow. I guess what I'm trying to figure out is what to ask of an aftermarket radiator mfg'er with reguards to burst pressure of the tanks and the core tubes. I've seen in the past that aftermarket radiators have suffered ruptured core tubes when T-stats were miss boxed.

Also, I'm sure that I'm not seeing the answer to this next Q in the system diagram, but what about flow to the heater core? Is that part not subject to seeing the same flow & pressure as the radiator?:o

TIA
:cheers:
Tom

[Tyler Townsley]

One thing to remember is that pump 'pulls' water in at the same speed it pumps it out so just what pressure the heater system sees may be different than what we expect. I once knew the name of the engineer who designed the system but time has put too many other things in and I cannot get it out. LOL Lotus spected the pump to put out 25 gpm at 1000 and 100+- gpm at 4k. To my knowledge I have not heard any Grant radiators failing and I talked to Dewit when he was developing his replacement radiator and was under the impression it was capable of ZR-1 water flows but you might call and ask him. I am using a fluidine as Hib H worked with them to make sure they understood the demands placed on the unit and Dewit did not have a replacement unit at the time.

Tyler

[tomtom72]

Tyler, thank you very much for sharing your info with us!:thumbsup:

I apologize to Mr. XFire for doing a hi-jack job on your thread.:o
It's just that this whole cooling system issue is making me think twice about what wisdom GM brought to the table.......most Z owners certianly do exceede 5k rpms with their cars I would think.....or at least I know I do when I'm doing the twisties with mine....again I apologize for the hi-jack.:handshak:

:cheers:
Tom

[XfireZ51]

Tyler, thank you very much for sharing your info with us!:thumbsup:

I apologize to Mr. XFire for doing a hi-jack job on your thread.:o
It's just that this whole cooling system issue is making me think twice about what wisdom GM brought to the table.......most Z owners certianly do exceede 5k rpms with their cars I would think.....or at least I know I do when I'm doing the twisties with mine....again I apologize for the hi-jack.:handshak:

:cheers:
Tom

Tom,
No worries. if this thread has coaxed some nuggets from Tyler, then its worth it.
In the meantime, I've installed my WB O2 in the car but now the weather isn't cooperating. I'd like to compare what my WB says to the one at the dyno. :hello:

[mrand]

It's just that this whole cooling system issue is making me think twice about what wisdom GM brought to the table.......most Z owners certianly do exceede 5k rpms with their cars I would think.....or at least I know I do when I'm doing the twisties with mine....again I apologize for the hi-jack.Howdy Tom,

Note that Tyler said "GM felt most owners would not operate the motor over 5500 rpm for any length of time so there would not be threat to any long term operations." I think this statement is correct. GM sold these as street cars, and high speed blasts on the highway or deserted roads certainly isn't a problem. Drag racing isn't a problem. Even SCCA racing with them isn't a problem. Only the few owners that take their ZR-1's to a high speed road course and manage to sustain high RPM operation would see this problem.

Engineering is about lowest cost for your target market, and I'm sure that sustained high speed road course operation wasn't in the design goals.

Have fun,

Marc

[Paul Workman]

Lane Goldstein (Fastlane) used a switch in the cockpit to turn on his fans with engine off to cool down his motor between runs. You can do the same thing by turning off the motor but leave the ignition on and turning on the A/C both fans should come on.

Tyler

Fascinating thread!:thumbsup: Whenever this topic comes up (not just with LT5s exclusively) it occurs to me that unless one also had an electric water pump, there wouldn't be much (or any) significant water circulation thru the radiator when the engine was not running. So, running the fans would only cool that slug of water in the radiator, and except possibly for miniscule(?) flow due to convection currents (cold sinking, hot rising, etc), there would be little cooling of the engine itself, no? And, once the temp of the thermostat was reached, even convection current would be cut off when it closes.

Just thinking out loud here -- I suppose with continued cooling, the slug in the radiator could eventually sink to ambient temp, so when the engine is re-fired, there would be a sudden overall temp drop as the cool slug from the radiator is mixed with the water that remained in the engine's water jacket; how much the temp would drop would depend on the temp differentials (radiator vs. block) and the proportions of hot and "cold" water being mixed.

Ignorance is bliss, or in my case, makes me dubious; re cooling fans significantly cooling the engine at shut-down, especially w/o an electric water pump. But, then again...I could be "all wet".:redface: If time is of the essence, every little bit (of cooling) helps, I suppose.

I think I'm saying that unless there is a water pump involved, running the fans is not going to be nearly very effective in a short time. In the absence of an electric pump, I suppose the engine could be fired for a few seconds to force an new slug of (hot) water from the jacket into the radiator, thus expediting the cooling. (Kinda makes one ponder getting an electric water pump, huh?)

P.

[tomtom72]

Mr. XFire thanks! Good luck with your new diagnostic/research equipment! I will look forward to your findings, which I hope you share with us!:thumbsup:


Marc, I guess I should have phrased "doubting the wisdom that GM brought..."
in a different way. I wasn't trying to be insulting to GM, et al.:o
........But I'm guilty as charged with the 5k rpm thing....I guess I get carried away with corners all strung together. I know I can "see" the spike in temps after awhile, water goes up and then the oil starts to climb if you're too high in the rpm band for too long. I notice it if I'm using 2nd & 3rd more than 3rd & 4th for more than 15 mins..... you keep bumping up against that 'circulation/by-pass limit'. I know the easy answer.... don't do it at all. It just seems to me that it's such a waste to have all that "room" on the tach, a balanced forged crank & rods, and No Push Rods!.....and not being allowed to use it.......for very long periods of time....it's just not fair!:sign10:

:cheers:
Tom

[mrand]

Mr. XFire thanks! Good luck with your new diagnostic/research equipment! I will look forward to your findings, which I hope you share with us!:thumbsup:


Marc, I guess I should have phrased "doubting the wisdom that GM brought..."
in a different way. I wasn't trying to be insulting to GM, et al.:o
........But I'm guilty as charged with the 5k rpm thing....I guess I get carried away with corners all strung together. I know I can "see" the spike in temps after awhile, water goes up and then the oil starts to climb if you're too high in the rpm band for too long. I notice it if I'm using 2nd & 3rd more than 3rd & 4th for more than 15 mins..... you keep bumping up against that 'circulation/by-pass limit'. I know the easy answer.... don't do it at all. It just seems to me that it's such a waste to have all that "room" on the tach, a balanced forged crank & rods, and No Push Rods!.....and not being allowed to use it.......for very long periods of time....it's just not fair!Howdy Tom,

Certainly not going to disagree with you. I've seen the temps climb several times as well on the track. It sure would have been nice if they'd put more money and effort into the cooling!

Marc

[jonszr1]

since i only drag race , what i do is turn the fans on for 5 min in the staginging lanes then fire the motor for 1 min and shut it down . i do that every 15 min and my coolant temps go way down . in 1/2 hr . . if i push the car most of the way up the line i can leave the starting line @160-5which seems to help power a bunch over being @180-190

[tomtom72]

Howdy Tom,

Certainly not going to disagree with you. I've seen the temps climb several times as well on the track. It sure would have been nice if they'd put more money and effort into the cooling!

Marc

:thumbsup: Marc! :cheers:

I should say that when I got my car the orig owner told me to read HOTB. I read about the cooling system and thought that's kind of dumb. I kept it in mind when driving, but the first time I actually saw it's effects I nearly had a heart attack. I ran back to the barn & changed the oil & filter, like a dope, as if that was gonna do anything....The one thing that I never knew was what Tyler related about the oil cooling system.....now that scares me as I was thinking well okay the radiator stinks & all with the by-pass, but I still have an oil cooler and that will help..... I was thinking that at least if the oil was getting cooled that it could take some extra heat loading, the cooler and using synthetic oil would be okay....well I just figured it would be safe...I think I figured wrong.:redface:

:cheers:
Tom

[Tyler Townsley]

since i only drag race , what i do is turn the fans on for 5 min in the staginging lanes then fire the motor for 1 min and shut it down . i do that every 15 min and my coolant temps go way down . in 1/2 hr . . if i push the car most of the way up the line i can leave the starting line @160-5which seems to help power a bunch over being @180-190

That was Lanes technique too. In his later deck plate engine (431 ci) he added an electric water pump to help stablize the water in the block to what was in the radiator. He also tried to have the water temp at 150 deg when he cranked to stage and 160 deg as he left.

Tyler

[jonszr1]

what brand of electric water pump did he use and was it hard to make fit ./? i would really like to do this . as well as figure a airconditioning delete setup on her . has anyone done this . every little bit helps .

[Tyler Townsley]

what brand of electric water pump did he use and was it hard to make fit ./? i would really like to do this . as well as figure a airconditioning delete setup on her . has anyone done this . every little bit helps .

I think the car is still at the NCM. Don't remember what type it was but it was plumed into a stock one with the guts removed.

Tyler