I have a werid situation :S . I race a 95 cavalier on 1/2 mile asphalt track and have the fastest car out there. But when the green flag drops I have no torque and everyone just blows past me so I have to work my way up the field. Now I can catch most of them, but our track does not give us enough laps so I do not have enough time to catch the 2 guys ahead of me and always always.... get third ( I have the fastest time in qualifying) . Lol I am tired of getting third and I was wondering If theres any small things or anything I can do to get more torque because it all adds up in the end . I Was thinking of those Rk sport engine mounts, Aluminum rims, Or smaller tires??

Thanks,

Jo Brown #25


Remember when sex was safe and racing was dangerous .

well by looking at your profile id say you want to add a muffler or something in the the line of a little resistance in your exhaust



8 psi with m62 and IAT under 100

Sorry I should really up date that. The motor is a fresh rebuilt with cold air, header, 2.25 exhaust to a magma flow muffler.


Remember when sex was safe and racing was dangerous .

Cody Star wrote:well by looking at your profile id say you want to add a muffler or something in the the line of a little resistance in your exhaust

please, oh PLEASE give me a reason why you think a restriction in an exhaust system is a good idea. go ahead, i'll wait.



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I can vouch for the OHV guys hurting with no exhaust. While less back pressue helps tremendously on the top end, it completely kills the bottom end and part of the midrange on the stock 2.2. I had a 92 cavy and for some reason I had to cut the exhaust right before the cat, i cant remeber. the few days it was runnging like that it was a dog. had no power before 4000 rpm and not too much after that the cam ran out of umph. hooked the exhaust backup and every thing was fine again. Now with a DOHC they love it.

to the OP smaller tires will help as long as you dont max out your rpm before the end of the straightaway. also maybe some 1.6 roller rockers to give your engine some umph. also the port and polish you have in your future mods will help. some say the head is the bottle neck in the engine. just remeber not to get rid of the vein in the exhaust port, just shave it a little.

Okay sweet thanks. I was going to go with smaller tires anyways I need more out of 4th too. Im running 195 55 R15 V and was thing of going to a 50 or 45?? Do you think Ive lost alot of back pressure and torque going with the header and 2.25 echaust :S I have a muffler tho.


Remember when sex was safe and racing was dangerous .

I think with that setup you should be ok, my issue was with no muffler and about 2 feet of pipe. Im not sure what size tire to recomend since im not exactly sure on the math as far as rpms at the end of the straight away. go too small and you might run out of rpm before the turn.

Start in a lower gear and shift?

I have alot left to spare in 4th so im going to a smaller tire. I usually start in second at 5500 but it changes alot because the guy leading the pack controls the speed so sometimes if hes going faster ill have to go to 3rd.


Remember when sex was safe and racing was dangerous .

Rather than "back pressure," what you're looking for is "scavenge effect." They make special mufflers for this type of application. I haven't looked in a long time, but I'm sure you can google it and learn more. Also, smaller tires, solid mounts, and headwork will definitely help out; but the answer is in a custom cam; whether brand new or reground. The cam dictates the powerband and it's characteristics, end of story.


"In Oldskool we trust"

Read Exhaust Backpressure, the myths. You don't want backpressure, you want velocity. If you go too big, you lose the velocity for the stated savaging needed to help the motor at a specified rpm. 21/4" is fine for these motors, as long as the diameter remains consistent through the entire exhaust system. I bet the header has one of those short ball and socket collectors. After the primaries, the collector has the next biggest effect on the characteristics of the header has on the motor. They are too short and disrupt the exhaust flow velocity. Look into getting a merge collector and replace the collector that on the header.

The proper cam regrind will make a huge difference on the powerband. The stock 2.2L cam leaves a lot to be desired, especially on a racing motor. Increased lift, tightened lobe centers and longer duration are needed for you application. Rocker arm ratio and cam phasing can affect the characteristics also. With these mods, you'll need the correct valve spring and the hybrid LN2-LS6 lifters to keep the motor running strong and sound.

Bigger valves and a good valve job can make a big difference.

Increased compression will help also. Look into what Bob Guptill has done, or zero deck the block and surface the head. This engine work will affect the valve train geometry, so you'll need the proper length pushrod and adjustable rocker arms, to prevent damaging the motor.

Of course all these mods are dependant on what your track rules allow, if you want to push those rules and how far you want to push them.


Edited 1 time(s). Last edited Sunday, June 06, 2010 5:27 AM

Have the good ole method of power braking? Works wonders on my dirt track, we run on a 3/8 mile track, decent amount of banking, i run 2nd gear with 205/65/15's and just as im about to hit the corner i hit the rev limiter, but when i come down on restarts i got the gas pedal to the floor and im hitting the brake as much as i can, when they throw the green flag i just shoot right to the inside of the car infront of me works everytime always good for a position or 2 before the 1st turn. plus since we lineup races according to point avgerages i always start in the back, so you gotta do whatever you can to grab spots.

Well it seems now my brain is bleeding ever so slightly after reading pages and pages about Exhaust and cams and what not. I learned a lot thanks guys, lots to think about now .


Remember when sex was safe and racing was dangerous .

If you just need more oomph down low, you should zero-deck the block, add 1.6:1 rockers, and, most importantly, move to a 4-2-1 header if you currently have a 4-1.
A cam could help with top-end, but it would sacrifice low-end.

Zs Z wrote:I can vouch for the OHV guys hurting with no exhaust. While less back pressue helps tremendously on the top end, it completely kills the bottom end and part of the midrange on the stock 2.2. I had a 92 cavy and for some reason I had to cut the exhaust right before the cat, i cant remeber. the few days it was runnging like that it was a dog. had no power before 4000 rpm and not too much after that the cam ran out of umph. hooked the exhaust backup and every thing was fine again. Now with a DOHC they love it.

Agreed. I cut off just my muffler one day, long ago, and it felt like it was running at half-throttle. Very strange.




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