Anyone have a good link to Cheap A$$ Mods? - Chevy Impala SS Forum
 
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post #1 of 8 (permalink) Old 03-03-2006, 11:11 AM
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Hello, I'm new to this forum. I used to race a 92 caprice 9C1 on a dirt oval and had pretty good luck with the cheap mods. I just bought a 96 Caprice ex Cop car and am looking for cheap Mods for it because by the rules we are limited on how much we can change the engine from stock. I've already found the Throttle body coolant bypass, Cold air intake, Coolant temp resistor, 160 thermostat, mods. Does anyone have a link to anything else that might prove helpful? Any input would be greatly appreciated. Thanks in advance! http://home.mchsi.com/~syberjay/

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post #2 of 8 (permalink) Old 03-03-2006, 11:43 AM
kdrolt
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OK so the 92 is retired from dirt racing, and you'll be racing the 96 now?

You obviously removed a lot of weight from the 92 since it was riding so high on the stock springs (as seen in the pix on your website) -- you'll have that problem on the 96 and it hurts the cornering, so cutting the springs slightly will help.

You'll gain some power by replacing the stock muffler with a very low restriction one. The engine can make a lot more power with a larger cam but I don't know if rules allow that. If you have to use a stock cam, you could always index the cam's position depending on what you want from the engine.

Why don't you post the rule basics first; that'll help guide the replies to your question.

Also, since I'm a 93 owner, tell us what you did to your 92.
post #3 of 8 (permalink) Old 03-03-2006, 09:38 PM
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Yeah, The 92 is retired, and I'm trying out the 96 for the first time this year. The 92 did ride a lot higher than the 96 is sitting now, and I've only removed wieght from the rear of the car so far. It's hard to get a feel for the ride hieght in those pictures though, because we are going balls to the wall in the turns and it rolls over a lot. we did try to heat up the left rear spring, but we found that we had quite a push in the turns at our local 1/4 mile mid banked track, but it worked well at a 1/2 mile flat track.
With the 96, were gonna cut out the cats, as long as it doesnt mess with our o2 sensors, it didnt seem to make a difference on the 92, but it only had one sensor. By the way, a stipulation for our class is we have to pull a plug wire on one cylinder to make it dead, and even when we pulled it on the side the single o2 sensor was on in the 92, I couldnt notice much of a difference. Even the laptop didnt pick up a rich conditiion. we pulled out the pushrods for that cyl on the first motor we ran because we thought it would throw off our fuel mix, but that just ruined that cylinder, so on the second motor we varied which cyl was dead from week to week.
We will eventually cut out the mufflers too, I'm curious as to what it will sound like with just the resonators on. The 92 had straight pipes out of the manifolds about a foot long, but it was really loud, and my nieghbors werent too pleased when we worked on it at 2 am!
We are not really able to change the cam, legally anyway. The rules are pretty basic, Don't do anything to the motor, but the techs let a lot of stuff slide, mainly eliminating things, but no aftermarket parts. I know a lot of guys do swap cams at our track, but racing takes a lot of $ that we dont have right now since we just bought the car, and time is running out to rebuild it. Maybe next year.
For the 92, We tried the resistor in the coolant sensor trick, and made the fuel pressure regulator adjustable, that proved to be a constant measument to check though because it always wanted to run too rich, worked nice when the weather was cooler thoough. We tried putting a plastic butt connector in the map sensor hose as a cheap delay valve, but we ran WOT most of the time so it's effects were hardly noticable. I took a die grinder to just about everything in the induction system from the air box, through the TBI down to porting the heads, that I feel made quite a big difference, and we made a dual snorkel "ram air" type air box with a K&N filter.(which was a godsend because we cleaned dirt out of it every week) We eliminated all the pollution control crap, including the egr, which now I'm wondering had a negative impact from some of the posts I've read, but it was hard to tell because I did that right away before we raced it. We surfaced the heads and got the thinnest head gaskets we could find. We got rid of any extra wieght possible, and made sure we had bilstien shocks(which are stock on a police car so we didnt break the rules there). Bigger fuel lines, and I made a TBI spacer plate out of 1/2" aluminum,and tripled the injector pod gaskets so they would sit higher. We also got a stage 2 chip for it. Thats about all I can think of right now,thats probably enough to read anyway!
http://home.mchsi.com/~syberjay/
 
post #4 of 8 (permalink) Old 03-04-2006, 07:59 PM
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post #5 of 8 (permalink) Old 03-04-2006, 09:45 PM
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Hey Thanks a lot guys! This gives me quite a few good ideas. I'll post back after I get to racin and let you know how things are goin.

http://home.mchsi.com/~syberjay/
post #6 of 8 (permalink) Old 03-06-2006, 09:59 AM
kdrolt
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Quote:
Originally posted by Cyberjay:
[QB] .... we did try to heat up the left rear spring, but we found that we had quite a push in the turns at our local 1/4 mile mid banked track, but it worked well at a 1/2 mile flat track.
The front springs can be cut, and supposedly the rears can also if you are careful. Heating, to deform springs, isn't suggested unless you retemper them. You'd be better off cutting them to achieve the desired ride height but don't do it until after all the wgt removal, and better to cut too little than too much.

Quote:
With the 96, were gonna cut out the cats, as long as it doesnt mess with our o2 sensors, it didnt seem to make a difference on the 92, but it only had one sensor.
It might be cheaper/easier to gut them rather than to cut them.

Quote:
By the way, a stipulation for our class is we have to pull a plug wire on one cylinder to make it dead, ...
Interesting. Then on the 96, you ought to always pull the plug wire AND disconnected the fuel injector for the same cylinder together. That way you will be more economical and have zero fuel wash in the unfired cylinder.

Just remember to unplug/plug the spark wire and the inector wire together in pairs. I don't know if the PCM will balk if it sees one injector disconnected so what you could do is attach a dummy load to that injector plug (either an injector that's not sitting in the fuel rail, or a high power elec resistor with the right resistance in ohms). Either way you do this, you would make a wire extension on the extra injector/resistor so that the long wire extension can reach any of the 8 real fuel injectors. There is no performance gain in this, but it does make it cleaner.

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and even when we pulled it on the side the single o2 sensor was on in the 92, I couldnt notice much of a difference.
The older ECMs never go into closed-loop operation with O2 sensor feedback while you are at WOT, or large angle throttle. There is very little info that the single O2 sensor provides at WOT other than the ECM making sure the mixture is always rich under certain conditions, and that's solely to avoid the engine from ever running lean enough to burn a hole in a piston. So in your case, it's not a surprise that you saw next to no difference because you don't drive on the track in steady-state speed and part throttle.

Quote:
Even the laptop didnt pick up a rich condition.
It wouldn't because the narrowband O2 sensor used on the 91-93 and 94-96 doesn't have the ability to sense richness other than extremely rich. The sampling rate isn't fast enough and the narrowband O2 sensors are only accurate in the region of the voltage zero crossing. So if you were using the laptop (and WINALDL) to monitor the stock O2 sensor, especially for a racing application, you were probably wasting your time. You would need a wideband O2 sensor to make that exercise useful, and that's true for both the TBI car (your old one) and the new 96 9C1.

Quote:
we pulled out the pushrods for that cyl on the first motor we ran because we thought it would throw off our fuel mix, but that just ruined that cylinder, so on the second motor we varied which cyl was dead from week to week.
That's a better practice, and on the 96 it's made even easier because you can disable the plug (via plug wire) AND the fuel injector (by disconnecting the connector atop the injector).

The gain in removing the pushrods would be preventing the cylinder from pumping air through it. I don't know why the cylinder was ruined because the intake valve should have been closed... so in theory no fuel should have ever gotten in there. OTOH residual fuel may have leaked it's way into that cylinder if the valve seat -to- intake seal wasn't great.

On the 96, you might still try the pushrod removal (even though it's more work) because you'll reduce the air pumpimg loss of the engine.

Quote:
We will eventually cut out the mufflers too, I'm curious as to what it will sound like with just the resonators on.
Loud, but the resonators will help quiet things and losing the mufflers + cat innards will help a lot.

Quote:
... We are not really able to change the cam, legally anyway. The rules are pretty basic, Don't do anything to the motor, but the techs let a lot of stuff slide, mainly eliminating things, but no aftermarket parts. I know a lot of guys do swap cams at our track, but racing takes a lot of $ that we dont have right now since we just bought the car, and time is running out to rebuild it. Maybe next year.
Is it legal to use an LT1 cam? i.e. an LT1 cam from a Camaro? It would give you more lift and duration. Cheap too (as the Fcar LT1 owners frequently do cam swaps).

You should keep the stock air cleaner for the 96 as it isolates the underhood heat from the air intake. Drill the lower air cleaner box on the front and side to allow more airflow. Use the stock paper filter so you can change it after each race. Consider using two if them if you can do the pumbing. The intake resonators can be kept because they really aren't flow restrictions, but the MAF screens are. Your engine can also be PCM setup for speed density mode so it won't use/need the MAF. You could leave the MAF in the car, but gut the screen and resistors, so it would look bone stock.

A 3.42 rear end (the center) from the 92 9C1 will fit into the 96, and the off the line response will be quicker... but on dirt you might not want the extra torque gain from it.

Make sure you do the proportioning and metering mods to the combination valve.
post #7 of 8 (permalink) Old 03-08-2006, 12:24 AM
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Yeah that was one of my biggest concerns, how the computer was going to react to the dead cyl. We have to have the sparkplug wired to the frame so the tech inspectors can see it spark so they know we arent cheating. I never thought of putting a dummy load in place of an unhooked injector though, I'll have to look into that. Thanks for the idea!
I'm still a little leary about pulling the pushrods though. It gets to be a pain to have to move them around from cyl to cyl each week and I'm worried about the other cylinders becoming too lean because the metered air is adjusting the fuel for all 8 when we are only running 7. but if the a/f ratio is set at a constant for WOT it would only affect us in staging while we idle, and caution laps, etc. I'm sure we could use a lt1 cam from a Camaro and get away with it, Technically it's not a stock part for our car so they would say no if we asked, but they would never be able to tell. They have the capabilty to check the lift and duration at the track, so I doubt a camaro cam would throw up any red flags, but we only have 3 weeks to finish the car, and no time to do a cam swap, or money, racing is too damn expensive without sponsors.
I already eliminated the first base/home plate as well as the maf screen, I drilled the holes in the airbox, but we are planning on getting a K&N filter because its easy to wash it every week, plus it flows much better. What affect does eliminating the MAF resistors do? Is that the speed density mode you are talking about?

I'm pretty sure the car now has 3.08 gears in it, the 92 had 3.42 and we rarely got above 4000 rpm at the 1/4 mile track with those, and we run in 2nd gear all the time. 1st gear is way too steep, but we have to run that gear even though I read it has less torque to the wheels for getting the car out of slick spots(like rocking in the snow)but that might be only at low speeds. We switched to a 3.73 and could reach 4500 rpm average. As soon as we get the time we will pull those out of the 92 and put em in the 96 as long as it can take a 8.5 ring. That is unless we find out we can run in first gear with the 3.08 without risking blowing the motor, I'm comfortable reaching 6000 rpm at the end of the straights, but afraid prolonged practice of that will make us miss races while we rebuild.
I'll have to do some research on the combination valve, cuz I'm not quite sure what that is yet, but thanks a lot for the info, it's greatly appreciated!!!
http://home.mchsi.com/~syberjay/
post #8 of 8 (permalink) Old 03-12-2006, 12:02 PM
White939C1
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Quote:
Originally posted by kdrolt:
You obviously removed a lot of weight from the 92 since it was riding so high on the stock springs (as seen in the pix on your website) -- you'll have that problem on the 96 and it hurts the cornering, so cutting the springs slightly will help.
My 95 sits higher than that and its still stock.
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