Building my car. I have rule restrictions. Need Advice.

[Low Impedance]

I am centering my 1991 Talon Tsi AWD (5spd) for Prepard Class Rallycrossing.

Basically i am limited as to what i can do to the car. Of course this is not going to stop me from trying my damnedest to make more power.

1. I cannot change or add turbochargers or intercooler. So i must use the stock SMIC and im going to use the 14b. Now im not sure if that means i can port this or alter the unit as long as i am not changing the unit with another non-stock model.

2. intake upstream of Throttle Body is free.

3. cylinder head back exhaust is free BUT its must exit to the rear of the car, from the body work, meet noise level requirements and have one functioning cat.

4. Clutch is unrestricted.

5. Electronic engine controls can be piggybacked.

6. Fuel must be from standard pump. (94 octane is highest available here at pump).

7. Air Filter is free but must fit in stock location.

Doesn't seem that i can have different injectors on the car. I cannot change cams, pulleys, heads, etc.

Ideally, the more low-midrange power i can get, the better. If there are methods to sacrifice top end to meet this goal, please inform me.

Based on the above. Here is my plan:
1. DSMlink for piggybacking ecu and datalogging.
2. Stock 14b and intercooler. Not porting the wastegate.
3. stock diverter valve w/ hard charge pipes.
4. tubular exhaust manifold to the 14b, aftermarket o2 housing (w/ dump?). 2-1/2" maybe 3" back exhaust of the custom variety to ensure compatibility with my skidplates.
5. some kind of good clutch. thinking 4 puck.
6. 94 octane all the time.
7. Cone filter and improved Turbo inlet Duct.

I have a 190 Walbro installed in the car and i intend to use it.

So based on this, what are my limitations (im thinking the stock injectors...), what can i expect to have the most problems with, and how can i maximize low end power?

If i can use higher injectors, what differences will this make?

 

[Dream On]

If you can't use bigger injectors, I suppose you could turn up your fuel pressure a little, but I wouldn't recommend it. Larger injectors will let you run higher boost, if you're allowed to that is. Many say the stock fuel system is only good for ~15 psi.

 

[HondaStylez]

Your plans sounds excellent, I agree completely. Don't let anyone talk you out of the tubular as they will surely try to. This will make an enormous difference in spool time and response which is exactly what you're looking for in your rally car.

You might be able to get away with smaller diameter charge pipes to help with even quicker spool, better response, and hence better low end. You'll have to experiment with how small you can go without losing top end flow/power.

Definately go with the externally dumped O2, if it will meet noise requirements (don't see how it wouldn't, they can't test it). And not porting the wastegate was a good call, I like you already.

Are you allowed to use a boost controller? If not, then there's no reason to get bigger than stock injectors. Even with all those mods, stock injectors won't be overrun at stock boost or whatever you might creep to with the exhaust. If you can run bigger injectors, I'd suggest running with the wastegate welded shut and tune the car to run this way. That will be the maximum of spool time and low end power that you want and the 14b will run out of breath before it hits any engine damaging power level.

Don't forget, very rich tune for road/rally racing. 10:1 or less is your friend.

Good luck with the build up.

 

[jking29]

What exactly do the rules say about manual boost controllers, injectors and maybe water injection? If manual boost controllers are allowed and you can change injectors, I would say that a boost controller and a set of 550's will help a great deal and allow you to run more boost. Also what do the rules say about intercooler piping? Hard piping will definitely help with airflow. Do the rules say anything about mass air upgrades? If not a 2g mas will help flow and tuning especially with 550's as well as getting rid of fuel cut. If the rules do not disallow water injection a set up with dual nozzles, one before the smic and one at the elbow, will allow you to run the turbo past its efficiency range without massive heatsoak and knock. With water injection you can shim the wastegate and probably get around 23-24 lbs of boost. Without water injection and the stock smic I would not try for over 18 lbs. I would also change the turbine housing to a 7cm if possible. It is not technically the turbo, and will help with flow. I would also port everything you possibly can except the wastegate, as it will help a great deal. Also a working Cyclone manifold would help low and midrange power a great deal. If you are going to run dsmlink it will be very easy to control the manifold through it.

 

[Low Impedance]

thing with SCCA rules are if they dont specifically say you CAN do it, then you cant. I might be able to do injectors because no one will care / notice.

As for alochol injection systems that is probably a no no. Intercooler spray might be okay. But not into the intake tracked.

I cant do anything to the throttle body/intake manifold/head. But i want low end power. High end is useless to me. Porting it will detract low end power, so i would want to do it anyhow. Hell i would consider a 2g head if i was allowed. Hell i might anyway. . Get them smaller ports for the low end torque.

i should be able to replace the MAF because its "intake (related) upstream of the Throttle Body"

 

[1gcrazy]

thing with SCCA rules are if they dont specifically say you CAN do it, then you cant. I might be able to do injectors because no one will care / notice.

As for alochol injection systems that is probably a no no. Intercooler spray might be okay. But not into the intake tracked.

I cant do anything to the throttle body/intake manifold/head. But i want low end power. High end is useless to me. Porting it will detract low end power, so i would want to do it anyhow. Hell i would consider a 2g head if i was allowed. Hell i might anyway. . Get them smaller ports for the low end torque.

i should be able to replace the MAF because its "intake (related) upstream of the Throttle Body"

T25? Shit if you're looking for low end thats the king, its stock.........on our older brothers.... Also, since our engines are the same as the E3's why not beable to interchange the injectors? Can you take some material off the head to raise compression just a tad. I bet you could move each cam over a tooth either way and get away with it... if it runs right with your config that is...
Can you enlarge your throttle body? 60ish mm maybe? Man this is harder than I thought...

 

[Low Impedance]

i cannot alter the throttle body on down. I also may not be able to change the MAF becauses its "changing the electronic engine controls". I may try anyway...

Not sure if i want the T25 though. Might be just TOO small.

 

[My91TalonTSi]

If you can do injectors, then by all means, change them.

As far as the turbo goes, you could probably get away with a 16g because it has the same td05h housing as your 14b, correct?

Also, you will need to keep the stock SMIC or a stock appearing one. How about a dejon tools or supra sidemount?

Just throwing some things out there. Sounds like a fun project. Enjoy