building for SCCA Solo BSP

[batchman]

Last year I campaigned for and received a rules change allowing update/backdate with all C4's together. This allows my (ok, my wife's) 91 ZR-1 with quick rack to be a legit entry in B Street Prepared. This year I'm getting back to sorting the car, with hopes of not getting killed by rally cars too terribly, at least on a regional basis LOL. So far so good with this site, good info here, thanks much.

But I think I need something like a wiki for low-impact power mods. *SP mods are reasonably open on induction (up to 1" into the head), exhaust, emissions and tune. So I find myself with some questions, and hit/miss success with search here. Perhaps with some help weeding through it all we can help carry the torch for Beasts everywhere.

Car currently has Watson headers, (I think) Random cats, Borla catback, a K&N drop-in, a DRM chip, and that's about all I can find for pre-existing power stuff. Dyno showed 335 at the wheels, looks like there's room for improvement.

1. Getting induction cool and dry. Seems straightforward to bypass the coolant in the throttle body, but doesn't appear feasible to dry out the injector housings. Is the upper plenum carrying coolant? If so, does it connect to the throttle body? Are phenolic plates the right answer from injector housing to plenum? Are they a common mod?

2. While I'm not wild about the idea, I think I'm going to be stuck port matching the heads without pulling them. I hope to go for plenum/IH/port match this winter. Any tips there would be helpful. Anything to be gained at the throttle body?

3. The car currently has a vacuum leak, and the vac pump appears to be bypassed. Since secondaries and brake booster seem fine, should I even worry about the pump? The vac schematic scares me some, mostly since it's clearly been messed with.

4. I'd like to remove the A/C and underdrive the WP/Alternator. I can't seem to find anything on the A/C delete, maybe it's fine for most but I'm worried about enough wrap on the power steering, which suffers a huge beating in autocross on big fat race rubber. Any resources/horror stories?

5. Any issues/benefits with removing emissions stuff? How/who to tune these cars? (sorry, my resources are all OBDII and Ford oriented) My state has stopped testing before OBDII, which is a good thing since this car is originally from Canada and emissions was always an issue, even with a stock PROM.

Sorry for having so many basic questions at once. Of course I'm also wrestling with suspension and brake issues at the same time. My hopes are higher than my budget at this point, but I'll feel a lot further ahead if I can formulate a plan.

For what it's worth, I'm also hoping to do a Fidanza, 3.54 gear, some sort of helical limited slip, and some sort of fix for the damned hubs and axle bearings.

Thanks for any comment!
- Jeff the hapless Ford guy...

[jonszr1]

335 seems a bit low for a car with your mods unless you are at 4k ft elev. you could contact corey henderson for the tuning andf injector housing and plenum porting. my car with fidanza jeal headers custom drgas exhaust porting by corey as well as tuning made 409.9 rwhp and 373.66 tq . you could contact either pete or randy woods of srp products about the air delelte. hope this helps and good luck this year

[Pete]

On the A/C you can remove everything with no issues.
You will need to run a shorter belt i think a 66 or 67 inch belt.

Pete

[batchman]

Thanks for the replies.

I had thought 335 may be a little soft, I am near sea level but in any case it's SAE corrected. 335rwhp looks like about 394 at the crank, the chip was worth about 10 (ran it both ways). I am not certain the cats are Random, but thought they were high flow.

The car has about 75k on it.

Any clues where HP falls off of these cars? I am figuring plug wires when the plenum comes off, do the coils degrade? They sure don't seem to be well located for cooling ;).

400 to the wheels sounds really good when considering some of the EVOs are hitting that. They don't scare me much, well there are a couple that do...

Thanks,
- Jeff

[Jeffvette]

Dyno showed 335 at the wheels, looks like there's room for improvement.

Almost every 91 I have seen has been down on power compared to 90's. My 90 made 339 stock.


1. Getting induction cool and dry. Seems straightforward to bypass the coolant in the throttle body, but doesn't appear feasible to dry out the injector housings. Is the upper plenum carrying coolant? If so, does it connect to the throttle body? Are phenolic plates the right answer from injector housing to plenum? Are they a common mod?

The upper plenum carries no coolant, other than the small passage from the injector housing to the pipes that are on the driver/passenger side of the plenum. Bypassing IMHO does no good, unless you cap it at the top of the injector housing and then the only benefit is when you pull the plenum in the future. The phenolic plates are another item that IMHO are money wasted. The motor itself is a big heat sink, and the heat radiates up. The only way to combat the heat is to make a injector housing/plenum combo out of injection molded plastic, or go to a sheetmetal intake design that allows more air to be pushed across.


2. While I'm not wild about the idea, I think I'm going to be stuck port matching the heads without pulling them. I hope to go for plenum/IH/port match this winter. Any tips there would be helpful. Anything to be gained at the throttle body?

Nothing to be gained at the TB until you start adding CI. Porting the top end will give you the most bang for the buck at this current point since you already have the headers. Port matching to the heads will make a difference as well.

3. The car currently has a vacuum leak, and the vac pump appears to be bypassed. Since secondaries and brake booster seem fine, should I even worry about the pump? The vac schematic scares me some, mostly since it's clearly been messed with.

The engine creates enough natural vacuum to run the car through the first few gears, top of third you should be running out of vacuum and 4th, is a waste. Since you are running autoX it can be left unplugged.

4. I'd like to remove the A/C and underdrive the WP/Alternator. I can't seem to find anything on the A/C delete, maybe it's fine for most but I'm worried about enough wrap on the power steering, which suffers a huge beating in autocross on big fat race rubber. Any resources/horror stories?

The power steering will have plenty of wrap, as the belt still has to come that way. Look at the diagram again, and as Pete said, I believe it is a 67" belt you are looking for.

5. Any issues/benefits with removing emissions stuff? How/who to tune these cars? (sorry, my resources are all OBDII and Ford oriented) My state has stopped testing before OBDII, which is a good thing since this car is originally from Canada and emissions was always an issue, even with a stock PROM.

You can remove the emissions stuff, what little there is. The air injection system can be unplugged and removed with no codes thrown by the ECM. Other than that, there is nothing left to really remove.

For what it's worth, I'm also hoping to do a Fidanza, 3.54 gear, some sort of helical limited slip, and some sort of fix for the damned hubs and axle bearings.



Fidanza will help in rev matching, but in the autoX group, you should be able to leave it in one gear and rev up and down with out changing again. of course this depends upon how your courses are set up.

3:54 gear set, find a set of stock gears.

The bearings, run the factory GM bearings, make sure you get some miles and heat cycles on them before you subject them to severe duty.

[batchman]

Since we bought this car it's had a soft brake pedal. Brakes are okay, will lock fronts on street, but it takes too much travel and too much effort.

Of course the first thing we did was flush the fluid. No sign of air.
Upgraded the pads, no change.
Switch to braided lines, no change.
Of course full flush each time.

Similar brake setup on our 88, and for that matter our 99 Cobra. Both those cars the brakes hit hard and are not an issue.

I gave up and changed the master cylinder, even though it held pedal steady once firmed up. Still a soft pedal, and maybe even longer travel. It's as if there is air in the ABS unit but I can find no specific method of bleeding same.

Have bled both by pedal and with a suction side power bleeder (venturi type). I've run at least 6 pints of fluid through this thing with all these successive attempts. Needless to say it's getting a little frustrating.

I'm going to try a pressure side power bleeder and open both wheels at the same time, hoping that with enough velocity we can sweep any trapped air out.

Other than the above we know nothing of the service history of the car other than it did in fact have a master cylinder and calipers. I wonder if there is any tech around for different master cylinder and caliper piston sizes found on C4s? Just because the MC we put in is fresh and labelled ZR-1 doesn't mean it's correctly sized. Similarly just because there are PBR calipers on this thing doesn't mean they're the right ones.

I think I will "trust nothing" until I can arrive at autocrossable brakes.

Thanks for listening,
- Jeff

[Pete]

Me and 3 others are using LS1 Camaro masters and never looked back.


Pete

[batchman]

Me and 3 others are using LS1 Camaro masters and never looked back.

Now that's very interesting. Does this mean we're not the only ZR-1 with what I'd have to call "73 Buick power brakes"?

I'll have to noodle a bit on what you did to use the LS1 part. While the master is open in this class there can be arguments surrounding how it's done.

Do you know the piston size in the Camaro Master?

Thanks,
- Jeff

[Jeffvette]

Me and 3 others are using LS1 Camaro masters and never looked back.


Pete


Using the same in my ZR-1 with the Brembo 4 pistons front and rear.

[Pete]

Now that's very interesting. Does this mean we're not the only ZR-1 with what I'd have to call "73 Buick power brakes"?

I'll have to noodle a bit on what you did to use the LS1 part. While the master is open in this class there can be arguments surrounding how it's done.

Do you know the piston size in the Camaro Master?

Thanks,
- Jeff

I know it has a bigger bore just never really measured it.

The early stock ZR-1 masters had some issues.

I made an aluminum spacer plate i think it was .150 or .200 thick to space out the master or you can cut the pin down so the master fits flush.

I will say the LS1 master has a much better petal feel.

Pete

[batchman]

Some research found all C4 stock master cylinders with a 7/8" dia piston, you guys are gaining pedal firmness with the LS1 master because it has a 1" piston - less pedal movement for the same amount of fluid movement. Right answer, but what did you do about brake bias?

After two different shops flushed the system I found the FSM calls for a non-intuitive bleed order, RF RR LR LF, which nobody was using. There is no process for bleeding the ABS in this year, same thing with our 88. I'm guessing this was enough of an issue over the years that they eventually added that capability in the last year or two of C4.

We popped the front line out to discover what type of flare (bubble) so as to prepare for an LS1 master, then re-bled per the FSM. Got a big burp out of the right rear. Funny, was expecting the air from opening the front to show up at front right. Weird, wonder if there's some sort of passage in the ABS to shunt air into a rear line?

Anyway, having used the entire 1st half of the season trying to get the car to autocrossable state, and with only two weekends until my major event of the season (Divisional), I'm going to take my much improved (but still lacking, call it 90%) braking to a test-n-tune "as is". Have to live with it for now, although I know the 1" piston is what I'm after - same setup as my 99 Cobra.

Now if I can just balance the front/rear grip some at this test-n-tune, have cross-weighting and a couple rear bars to try.

Thanks/later,
- Jeff

[mbabbitt]

Using the same in my ZR-1 with the Brembo 4 pistons front and rear.

I'm using a 3/4 ton Master Cylinder out of a '94 K2500 I believe, It has a 1 1/8" bore. I have the P/N from NAPA. It's a $30 part with no core charge. The pedal is high and hard 98% of the time on road tracks. After a 20 minute session braking down from 150MPH, the pedal starts getting soft just a bit. I'm running Wilwood GNIII's in the front and the J55 setup in the rear. The braking is good but ever since I installed this setup, I go thru EBTCM's way too much. Not sure what turns them to toast. Good luck in your brake endeavour....

[batchman]

I'm using a 3/4 ton Master Cylinder out of a '94 K2500 I believe, It has a 1 1/8" bore. I have the P/N from NAPA. It's a $30 part with no core charge. The pedal is high and hard 98% of the time on road tracks. After a 20 minute session braking down from 150MPH, the pedal starts getting soft just a bit. I'm running Wilwood GNIII's in the front and the J55 setup in the rear.

Now *that* sounds like a brake pedal with *authority*. Are your Wilwoods very different in caliper piston area from the J55? Did you do anything to alter bias?

Cheers,
- Jeff

[mbabbitt]

Now *that* sounds like a brake pedal with *authority*. Are your Wilwoods very different in caliper piston area from the J55? Did you do anything to alter bias?

Cheers,
- Jeff

The Wilwood GNIII's are ALOT bigger. Not sure how much though. Go to Wilwoods site and the dimensions are given. I'm using the Stainless Steel piston liners also. Can't remember what they're called exactly.

No bias change.

[batchman]

Well the Beast finally survived an event without a hitch, albeit a test-and-tune. Many thanks to Jeff at Turn One! The PS setup with the quick rack and 315s on heavy wheels has been tough. Add to that up to 70 turns in a mile and a half and well, that has been PS hell.

In prior events with the stock rear bar it was a little too prone to oversteer. Fun but not entirely quick ;). I pulled the bar and had one partial event where I was too able to get understeer, although I was thinking that some of that was driver induced. So for this TnT I hung a small bar but wired it out of the way, ran the morning, then at lunch hooked up the bar. It was a little more eager to rotate under throttle but not wildly so. Although track conditions improve through the day, making direct comparisons tough, I did drop a convincing full second from morning to afternoon. To me the car just felt better with the small bar, but of course that's got me thinking I should try to find a 24mm one for giggles.

All day though I would put a good gaff in every run, sometimes due to trouble judging the right side of the car, but mostly due to late braking which I attribute to the long pedal. I definitely need to do the Z28 master, and probably try to left-foot-brake. There is a danger that I'll set this up to be like my Cobra because after 8 years with it, that's what feels right. In the end though the big thing for me to worry about at the Divisional Championship next week is that this car is a big step from what I've been used to, making me get late pretty much everywhere as the car gets ahead of my butt.

Well that and finding a tire setup that doesn't include sending gold bars to Tire Rack, as much as I'd like to it's just not in the cards at the moment...

Later,
-Jeff

[batchman]

Well tomorrow and Sunday are my big event of the year, the SCCA Solo II North East Divisional Championship. Looks like a good BSP field, 3 Evos and an STi. The current wisdom is the Evo is the car to have. I think the Beasts should have something to say about that, at least on a dry day.

Tomorrow will be dry, Sunday should be too.

After last week's test-n-tune I had to replace all 4 hubs, then get 500 miles on them. Got a little stressful, came up with a front end "CLICK" made me think ball joint, but it was only a sway bar end link. I think I'm all prepped now. Just need a couple more course walks. 3 sections look really fast - good thing I'm still on the stock gear. I haven't found the rev limiter in this DRM chip, sure hope there is one ;).

With 3 year old tires I am bringing a knife to a gun fight, but at least it's a small bore gun fight, and a pretty big knife...

Wish me luck!
- Jeff

[Ccmano]

Interested to see your results. As an old autox'er I've often thought the Z would be fun to run.

What tires are you running? I see they're 315's all around but are they AutoX specific or street tires. As you no doubt know the right tires make some of the biggest difference in AutoX.

Good luck.
H
:cheers:

[batchman]

Thanks for the wish of luck. I'm going to need it.

After the 1st day I am .3sec out of 2nd in BSP. That sounds good but there are only 4 of us and the 4th place guy is running this as his 2nd event ever and is on street tires.

I am struggling a bit as the car is very fast and it gets ahead of me. What used to be decent discipline for looking ahead is now waaaay too late. At our site there is a large apron with a small bit of crown to it. The course had a long accel zone leading to a single right hook, maybe 25 or 30 degrees, to another long shot to a tight left. I think I was close to the 80mph and it was enough to make the small crown to the area unweight the front a bit. I've never had anything under me do that, and I've been driving various iron on this same site for 8 years.

You're right, tires are huge (as is alignment, and everything else for that matter ;) ). And of course, I run huge tires. I'm using Hoosier A6s in 315 front, 335 rear. They are absolutely the fastest tires but alas mine are now three years old. That's how long it's taken us to get this car workable. They still grip well but not anything like fresh ones. I'd take more solace in my results given that, but the class leader is on fairly used stuff too, although not old.

My theory is with the HP & tire footprint, coupled with the ability to firm up springs/shocks/bars, the Beast should be a real Beast. Today it was. Unfortunately I am not yet a Beast Master....

Tomorrow is another day. I don't have to run faster than the bear, I just have to run faster than the next guy LOL. If I can make up .4 sec I'll have 2nd. (this event is best time each day totalled)

Truly I am now a BSP guy with an FStock calibrated butt. That experience is not all bad though. Like the Beast my Cobra has a 4-valve motor that is not overwhelming down low. This got me used to using 1st gear in slower segments. Once I brought that logic to the Z my times started getting closer to competitive. There was a tight slalom right at the start, after feeling kind of flat on this segment and its exit, my 3rd run I held first through this. On my 4th run I smoothed it out and it was the right answer, much better dancing through it and much faster exit. Almost blew the next segment though. Also the exit had a tight slalom offset the non-favorable way, exiting to the finish. Slow enough for a downshift to 1st and launch to the lights at 7200 or so. I better figure out what this DRM chip has set for a limiter!

Can't count the number of comments on the sound of the Z as it gets wailing. Woo Hoo!

Best,
- Jeff

[Tyler Townsley]

Watch your water temps!! The stock designed coolant setup starts shunting the water around the radiator at 5200 rpm and by 5800 rpm you have no water flowing throught the radiator. You have hot water going right back into the block with no cooling. Do a search on thermostats for older discussion on this and recommended fixes. If the car is going to be used for autox I recommend a high flow radiator, cut the spring that controls the thermostat opening so it is always open and block the bypass. Do not do the spring and bypass without the higher flow radiator as you will blow out the sides of a stock radiator.

Tyler

[batchman]

Wow Tyler thanks for the tech. That's pretty non-intuitive but I guess they had to keep from blowing the rad's apart! I was thinking a UDP would help high rpm cavitation issues but what you describe is far more serious. I'll be watching this more closely and scheming to improve. Is the bypass controlled by the ECM and/or would this be a setting in the PROM?

Speaking of temps how are the guages as far as function? I did recently read of the HVAC display trick and will make that 2nd nature, but is the gauge an actual analog gauge as opposed to the idiot-meter that some mfgs started to use to limit service questions?

Also I have some concern on the oil temps. The oil temp gauge does move from dead cold but not past the "0" on "40" at the low end (Canadian car). In contrast I've noticed my wife's L98 with digital oil temp spike to 300 and a little over after a 40 sec autox run.

PS my 2nd day at the Divisional had me making somewhat better friends with the car but falling back some off the BSP pace. I clearly have some work to do - a few things on the car but the big nut at the steering wheel seems to need the most tightening at the moment.

Best,
- Jeff

[batchman]

Well I survived another event, thanks to phrogs quick ship on a new rag joint. The old one had 1/16th or so of side-to-side in the rag rivets, which is part of what made this car less crisp than my wife's 88 z51.

I'd been having trouble placing the right side of the car, since the different seating position plus the width of the car had me cautious. Some photo evidence shows I think I've found it.


This event was another angst fest but it was not with my points season club, so I used it as a test and tune. Further fighting with the car left me with a frustrating day, it was also blazing hot. I drank about 3 gallons of water and only hit the head once. At the end of the day one of my buds from the big club stopped in and I took him on a fun run, kind of yucking it up and not fighting the car. I went about one and a third seconds quicker. Clearly I have to relax.

I'm still on the small rear bar and thinking I'm missing the tractable oversteer from the big bar. At some point I hope to find a medium bar nearby.

I've swapped the brake pads with my Cobra (from PFZ's to Carbotech AX6s) and still need to bed them properly, but have a parking lot event on Sunday. Looking forward to that as they used to be a lot of fun in my Cobra. In that car I'd call this style course "a first gear romp in a fishbowl". I think the ZR-1 should have a similar demeanor to my car, high powerband, long rear gear, big fun. At least in a 1st gear event I should be able to get my oversteer with the light rear bar just fine ;).

Now if I can keep from worrying about the cooling system - thought I was having an issue with that last event but now believe it was just fuel starvation cutting the secondaries in one spot in my last couple runs of the event. This event the runs will only be 30-40 seconds so hopefully I'm not long above the bypass rpm. Still wish I knew how that bypass is managed - I have to be careful about rules. Is it just a pressure relief in the thermostat? Luckily the rules changed this year and seem to allow a bigger radiator.

Cheers,
- Jeff

[DaveK]

Sounds like you're having a lot of fun! :thumbsup:

[batchman]

Seems that despite intentions I didn't keep up this thread very well!

I did manage one class win in '09, in my favorite "fishbowl" event. Short course, 22 sec or so, there is absolutely no place to hide a mistake in a run that short. While my Evo running rival didn't make that event, the guy I beat was the eventual season points champ. Not a bad day.

The rest of the season returned to mediocrity though, but at least the car survived pretty much intact.

Since then I've pulled the AC but not yet yanked the compressor, ditched the air pump, gone back to a lightweight battery, and updated wheels (ccw 11's and 12's, thanks Matt!) with a fresh set of A6s in 315 & 335. Woot!

So far this year I've halved the gap to the front runners, and my Evo bud and his daughter made the first "fishbowl" event. I had them for most of the day, but my one fast run (that I thought was unbeatable) had a late cone call that I didn't know about :blahblah:. Sigh.

The new tire/wheel package is showing promise but the body roll evident in the above series is now worse as I've got more grip. I'm looking for a front bar (32mm), since the photographic evidence is irrefutable. I may need to think about offset control arm bushings too since said photos are showing me way out of camber, although the bar should help limit that a lot.

The good news is that so far this year I'm consistently ahead of my wife and her 88 Z51, now in BStock. The bad news is, never by much! I think a front bar may make a difference, and it's something that both of the BStock C4s have in place. Maybe with that I can start to gap them more like I should... That and continue getting my butt re-calibrated...

As I try to get ready for a plenum pull and yanking the AC compressor I'm back to belt questions. While I'm in there I hope to chase down some underdrive pullies, but won't be able to use the normal belt that "comes with". Since I gather the AC delete puts me to a 67" belt, what is the stock belt length? Maybe with that I can sort out what the UDP belt length should be.

I still haven't swapped the master cylinder, got sidetracked on making an adapter. A friend has just landed a Bridgeport, might be time to try wake that project back up soon. And I think it's time to yank some of the stereo stuff - I bet that's a fair amount of weight. Trouble is I don't know these cars very well - there are speaker enclosures by your feet, how do these attach?

Cheers,
- Jeff

[LGAFF]

You need a 4.09 gear, if you don't have one already

[batchman]

You need a 4.09 gear, if you don't have one already

Having seen what a 4.10 - 4.56 will do for a DOHC Cobra I very much agree. Unfortunately I'm limited by rules and can only go to the quickest ratio found from the factory, a 3.54. So I continue to watch for a low-miles take-out. I haven't figured out yet how to alter speedo cal for that but this is a ways off.

Good news is I can use any flywheel or diff though, so on my wish list is a Fidanza and a T2R, Tru-Trac or Quaife although I'm not entirely sure which are actually available for the d44 with half-shafts. At least the HD d44 has a really good lsd clutch setup. Stick axle Mustangs eat stock lsd setups in 3-5 events, at least the IRS ones go most of a season.

Anyone know the stock serpentine belt length offhand?

Later,
- Jeff

[tomtom72]

Hi Jeff, hey, you're having fun...sweet!

On the T-stat, our by pass is done using PSI by the T-stat itself and the housing has a port that shunts the flow back to the block. The ECM is not involved. Our water pumps put put out some big gpm, Lotus wanted it that way. Something like 125 gpm, I think?

On the oil cooler, there is a T-stat(?), in the filter adapter, that is at some really high opening temp, like upper 280's or so fully opened. I have heard that GM didn't intend it to be a real oil cooler, just something to prevent wild fluctuations in oil temperature due to the shear volume of oil in the motor itself, like almost 9 + qt. I'm told that it trickles at lower oil temps just to keep the temps stable, but it's not like they intended it to be a racing oil cooler.

Not to be a bother to you, but I'm really, really interested in this swap to the Camaro master cylinder and would be interested in anything you would want to share on the install and any thing that needs to be fab'ed up to make it work. I'd buy one of the adapters from you if you were willing to sell?

TIA & have a good season!
:cheers:
Tom