Blocking off coolant to plenum

[LGAFF]

CCMANO, TOYVET and I did some country driving.....during the course of the drive I got left in the dust by Hans freshly ported intake and headers.....when we got to the car show Hans told me how he had blocked off the coolant to the upper plenum..........also Hans noted that you can now put your hand on the plenum surface and not smell sizzling beef......or in my case more bacony smell.......anyway, the question is, what would the anticipated performance gain be from this mod? Seems this would do well when combined with a relocated IAT, fresh air induction, etc.

Any thoughts? I am not talking 20hp but one would think it would have some impact.

[Aurora40]

I'm bypassing the throttle body coolant, mostly because I noticed white flakey stuff between the TB and plenum, and it turns out the factory gasket corroded. I'm sort of sick of dealing with the crappy TB gasket, so I ordered up a Jerry's one, and I'm gonna go the extra step of bypassing the coolant altogether.

The plenum is probably a bit harder? Doesn't it flow up from the injector housing?

[-=Jeff=-]

I did it too.. not sure there is a performance gain, but i can pull the plenum in 15min without draining coolant..

Pete, Al, Dominic and Hans have this done

[Paul Workman]

I did it too.. not sure there is a performance gain, but i can pull the plenum in 15min without draining coolant..

Pete, Al, Dominic and Hans have this done

That right there is reason enough to cut it off, IMO!

As far as a performance boost goes resulting from cutting off the coolant to the TB, there is still quite a bit of heat radiating up thru the IH's too; cutting off the TB coolant can't hurt, but that is only part of the story. (There's a lot to be said for those plastic intake plenums used by the LSx motors; very low specific heat values, compared to aluminum.) So, I think a combination of cutting off the TB coolant IN conjunction with a Lingenfelter thermal isolator gasket, might make a bit of sense (or at least Lingenfelter thought so). We can't pack our plenums in ice, less we drown our starters.

I'm gonna dyno mine w/ and w/o the thermal isolator & TB bypass, hopefully sometime this summer. Ideally, I would do a few pulls, then make the swap, and then do some more on the same day, same dyno (the setup at the Mid America Vettefest in September(?) might be one venue for such foolishness).

Anyway...Goood question ya got there! :thumbsup: I'm interested too!:handshak:

P.

[XfireZ51]

I did it too.. not sure there is a performance gain, but i can pull the plenum in 15min without draining coolant..

Pete, Al, Dominic and Hans have this done

:thumbsup:

I have the drill and tap if you need it. The brass plugs come from Ace Hardware.
You can pull a plenum in 20 minutes.

[Ccmano]

I've often wondered if the claims made by Ron Woods on his ZR1Products.com site are legit. He claims a 19.8rwhp increase by adding Plenum and Throttle body insulators, Throttle body coolant bypass, light weight underdrive pullies, 145' Thermostat and an X-Pipe. He does post the dyno sheets. Check it out...

http://www.zr1products.com/

I have been considering the insulators.
H
:cheers:

[LGAFF]

Just to be clear, we are not speaking of a TB bypass, but blocking coolant off at the IH.

[XfireZ51]

Lee,

You are blocking off the coolant passage on the top of the injector housing which directs coolant to upper plenum and then to TB. Not the passage between the cylinder head and IH.

[LGAFF]

Yes, I knew that but was amazed at how cool Hans Plenum is now.

[secondchance]

I came accross an interesting calculator that calculates relative horsepower based on air temp, atmospheric pressue and relative humidity:

http://www.anycalculator.com/enginehorsepower.htm

Based on this 100 degree to 90 degree (10 degree differential) holding air pressure at 31 and relative humidity at 30% for both shows 102.2% and 104% respectively - translating to .18% hp differential per degree.

If this is true, for a motor of 350 hp, per 10 degree drop of intake air should result in 6 hp gain roughly.

[flyin ryan]

I came accross an interesting calculator that calculates relative horsepower based on air temp, atmospheric pressue and relative humidity:

http://www.anycalculator.com/enginehorsepower.htm

Based on this 100 degree to 90 degree (10 degree differential) holding air pressure at 31 and relative humidity at 30% for both shows 102.2% and 104% respectively - translating to .18% hp differential per degree.

If this is true, for a motor of 350 hp, per 10 degree drop of intake air should result in 6 hp gain roughly.That's the general factor we use for 'Intake Air'.

[LGAFF]

Can air coming in heat that quickly passing through the plenum?

[Locobob]

Don't expect big power gains from blocking off the coolant to the plenum and TB. I have mine blocked off and rerouted through the tops of the coolant pipes - to help bleed air from the system. I also have the phelonic spacers between the plenum and injector housings. All of this amounts to a 10-15 degree difference in plenum temps. This will help cool the inlet charge somewhat but not to the full 10-15 degrees. The benefits of this mod are 1. easier plenum pulls 2. less chance of leaks 3. a small performance gain - not much but a little here and there adds up.
I did an article on this subject for HOTB a year or two ago - check it out.

[XfireZ51]

Can air coming in heat that quickly passing through the plenum?

That would be my question also. :???: I think the "isolators" are not worth it from an insulating point of view. Now if you use a intercooler...

[Paul Workman]

That would be my question also. :???: I think the "isolators" are not worth it from an insulating point of view. Now if you use a intercooler...

Dom, you're right. Considering the mass of the intake and the IHs, and the specific heat of aluminum, compared to the mass of air taken in at WOT in the quarter mile, it is easy to see that the temp of the TB/Plenum is pretty small potatoes. First, the air temp is going to snatch the heat out of the intake etc like a candle in the wind; quickly gone for any practical concern over heating of the air. And second, the surface area of the plenum/IHs, etc are tiny compared to the core of an intercooler - a very inefficient heat exchanger, is my point. The heat transferred to the air is going to be minimal at WOT.

If we really want to take advantage that cooling the air (read: air density) provides, the intercooler seems like it might make sense. But, to get meaningful cooling of ambient air (e.g. down from say 85º to 30ºF) for a NA engine at WOT means the core is going to have to operate well below freezing al la -20 or -30ºF. Unfortunately, the water vapor would condense and freeze when coming in contact with a core that cold. It is one thing to bring supercharger air at over 200ºF down to 110º with the intercooler, but to keep from freezing ambient air/moisture, the IC core is going to have to remain above freezing, and that means much less efficiency.

But, still a 30º drop from 85º ambient would still mean around a 15 hp gain to a 400 hp base engine. The question is net gain, or in other words, how much power does the weight of the intercooler and coolant and coolant handling equipment cost in HP offset?


After doing the math, I've reconsidered bypassing the TB for any other reason than to make pulling the plenum easier. But, the intercooler...that intrigues me. (How 'bout a bottle of super-chilled water forced thru the intercooler beginning at the launch? Just thinking "out loud"...)

P.

[Aurora40]

How would you use coolant to bring an intercooler's core temp down below ambient temperature? Wouldn't you need a refrigerant?

It would seem like using the A/C on the intake charge. My guess is the power lost to run the compressor would offset any gain.

What about some kind of water/alcohol injection? You could presumably cool the solution ahead of time, keep it in a cooler on the way to the track, then fill the reservoir up before you make a run. I dunno...

Edit: I guess I skimmed your post, I missed the part about the cold water for the I/C. :)

[secondchance]

How would you use coolant to bring an intercooler's core temp down below ambient temperature? Wouldn't you need a refrigerant?

It would seem like using the A/C on the intake charge. My guess is the power lost to run the compressor would offset any gain.

What about some kind of water/alcohol injection? You could presumably cool the solution ahead of time, keep it in a cooler on the way to the track, then fill the reservoir up before you make a run. I dunno...

Edit: I guess I skimmed your post, I missed the part about the cold water for the I/C. :)

I agree running compressor would negate any gain.
Water/alcohol injection would work. If I remeber correct, Turbo Mustangs back in early to mid- 80s had water injection (I can't recall whether factory or aftermarket). I heard those cars were running into rusted spark plug problems.

[flyin ryan]

Don't expect big power gains from blocking off the coolant to the plenum and TB. I have mine blocked off and rerouted through the tops of the coolant pipes - to help bleed air from the system. I also have the phelonic spacers between the plenum and injector housings. All of this amounts to a 10-15 degree difference in plenum temps. This will help cool the inlet charge somewhat but not to the full 10-15 degrees. The benefits of this mod are 1. easier plenum pulls 2. less chance of leaks 3. a small performance gain - not much but a little here and there adds up.
I did an article on this subject for HOTB a year or two ago - check it out.Robert's right, gains will be small. If you want to do it for the sake of doing it, go for it...just don't have un-realistic expectations :neutral:.

[Locobob]

It would seem like using the A/C on the intake charge. My guess is the power lost to run the compressor would offset any gain.



Didn't Ford do something like this on the supercharged Lightning pickup truck?

[diamond zr1]

twin turbos mounted in the back,pushing forward thru a intercooler in front of the radiator,cooled with carbon dioxide bottles is the answer on my twin turbo car/check it out in the jan 09corvette mag.Hennessey uses a warer spray over the innercooler on his 09zr1/messey

[rkreigh]

considering the air velocity at WOT I think cooling the plenum down can help the ambient air temp/density all that much. the air is flowing so fast it doesn't pick up all that much heat from the intake. that said, the LT5 sure does wake up at cooler temps and run hard. when the engine is hot, power really does drop off, so maybe it's worth it. interesting to see a "back to back" dyno test on the same dyno with the same engine temps. that's the only way to really evaluate it.

when we talk twin turbos, now an intercooler really makes sense! on my turbo cars, just a bit of cooler air ramps up power tremendously. I rigged up a "cooling jacket" on my turbo buick so super cool the air to air intercooler by pumping ice cold water into a jacket around the end tanks. it really worked.

there is no doubt that increasing the air density and "quality" (dry air) helps the engine make more power. any internal combustion engine is after all and "air pump" so better quality air and more fuel make mo powa.

for giggles, we dynoed the LSV on a 55 deg day (woooo chilly!)

uncorrected rwhp was 536

corrected down to 508

but I can tell you, it's 536 hitting the ground, problem is cool tires and big hp don't mix all that well:razz: