Autocross Setup

Quoting junior392:
This may be a question that most people know already but I want to ask anyway. The BMW, Miata, Subaru 2.5rs listed above are all NA vehicles. In Auto Xing wouldn’t you want a non turbo car due to a turbo is lagy. I understand when at full boost and into the torque ban you have an advantage but shifting gears and on and off the gas while making turns could cause lost of time. I am not trying to discriminate against your build or interest just curious on why a turbo car for this type of motorsport? Thanks in advance. GL with your goals.



Thanks for the good luck wishes... I may need them /ubbthreads/images/graemlins/wink.gif Well, yes you are correct to a certain point. NA vehicles, especially ones with good torque are theoretically good at autocrossing, since coming out of tight corners you want power right now. However, on most courses you are always in 2nd gear, & the revs seem to go from about 3K RPM to redline & above. That being said, using a smaller turbo such as the 14B I will be running (or even the EVO 3 16G I ran before in SM) means you are pretty much always in the power band. Yes there is some lag, but I used to left foot brake a lot (need to polish up those skills again) which helps build boost coming out of the corners. Even still, if I have a little lag coming out of the corner, I can still use ALL of the available power with AWD. The RWD cars will always fight traction problems. Plus, I will always carry more speed down the straights if I have the power advantage I think I will.

A good example of how turbos can work better is the BSP class. C4 Corvettes used to dominate this class, tons of low end torque, good suspension & huge tires. Then the AWD rally cars (EVO & STI) got bumped into that class, & now the Corvettes are having a tough time being competitive. Big turbo power mated to AWD with the same big sticky tires equals a better autocrosser. Thats what I am thinking when it comes to the GVR4. Compared to the DSP class leaders, the Galant will have a lot more power, AWD, & the same big sticky tires. The only real downside is weight, but at the most I would be spotting the BMWs 200 or so pounds, not nearly enough to make up for a possible 100WHP advantage /ubbthreads/images/graemlins/grin.gif

Ted, you are right, I can easily fit the intercooler I have in the recess where the A/C condenser once was. This will allow me to put the stock bumper back on to be legal. You are also right that cooling won't be an issue at autocrosses, but if I track the car again I might not want to go out on a 100+ degree day /ubbthreads/images/graemlins/wink.gif

Also, everything Roger pointed out above is exactly right on. Intercoolers are open, just can't modify the bodywork to accomodate them. He is also right about the 16g turbos, you MIGHT get away with it at the local level, but never at the National level. Even then, in my local region we have a past National Champion that runs in DSP & others that have trophied at Nationals in the past, they know the rules as well as I do. Plus, I don't want to even think about cheating. I want to know I beat them fair & square if I am fortunate enough to do so.

Cy, your car sounds AWESOME! Unfortunately, a lot of the chassis mods you listed aren't legal, such as the 4 bolt diff, & eliminating the 4WS. I would be interested in the coilovers if you wanted to sell them seperate /ubbthreads/images/graemlins/wink.gif

Someone mentioned "update/backdate". Yes, this is allowed, but the cars you are using to update/backdate with need to be listed on the same line in the rulebook. It also can only be vehicles originally sold in the US, so the 16G turbo is no go (I sooo wish it was). The interesting part for us GVR4 owners is that in the rulebook under the DSP calss, it says "Galant All". So, theoretically, you could start with a base model Galant with no options & swap in a GVR4 drivetrain.... I think if this was done, you could get the car down to maybe 2600-2700 lbs /ubbthreads/images/graemlins/smile.gif

Once again, thanks everyone for the great advice & ideas, I can't wait to see how it does!

 

[belize1334]

For comparable power levels you will do better in autocross if you are running an NA setup. Especially in corners, throttle modulation is very important and with a turbo it just doesn't work well do to the delay and the short time scales of a low speed course. So, if you want to really cleanup you go either NA or supercharger. That being said, if you can put the traction down and a turbo puts you in another power level, then go for it since power is an advantage in any motorsport.

 

Hey Mark, glad to see you around!

I think you might be able to exploit some variances between stock Japanese versions of the car and the USDM version. IIRC, the GVR4 Evo came with a small 16g and a larger stock intercooler, in addition to the different bumpers. I think removing the body cladding would also be a good path to take for weight reduction.

I hope to get Dan's old black '91 running in the next few weeks; if so, I'll be driving it up to Mark K's to do the smog "up the hill." We might have to find a nice long gravel road and have an impromptu three VR4 stage rallye!

P.S. I have a set of new Azenis on the Miata now and am enjoying the difference thus far... /ubbthreads/images/graemlins/smile.gif

 

Hey Dave, good to hear from you! Yes, we definitely need to get together sometime soon to talk cars /ubbthreads/images/graemlins/grin.gif Did you ever get the email I sent you a little while back? I left my number on there, give me a call sometime.

I wish I could get away with the JDM thing, but unfortunately it's against the rules in autocross. The update/backdate thing only works for USDM cars. Update/backdate works good for the DSMs though, since all the AWD cars are listed on the same line in the rule book in ESP. So, the hot set up in that class would be a 2G car with a 1G 6-bolt swap & 14B. I think that could be a winner in ESP if set up right....