Which modifications for engine rebuild?
 

So after driving (and auto crossing) with a cracked apex seal for 2 years, it finally went. I've taken the car in and have several options for the rebuild. Here's a list of some mods that can be done, which ones do you think have the most benefit and what else would you recommend.
I have a new ACT HD pressure plate and SS clutch disc, ACT Streetlight flywheel with counter weight as well. New engine wire harness, primary injectors etc.

Options
1. Mild street porting on exhaust and intake (was thinking only exhaust)
2. Engine balance with new flywheel and counter weight
3. 2mm or 3mm apex seals (2mm recommended by builder)

Not looking for big power, just use car for fun driving and auto cross. Other engine mods on car include.
1. Power FC
2. FEED down pipe and RB catback
3. Efini y-pipe
4. Replaced a vacuum hoses with silicone hose
5. Aluminum rad

What kind of budget are you working with? For porting I've heard you don't NEED to re-tune if your street port isn't too aggresive, but honestly I'd factor the dyno time into any porting service you get done.

I vote:

Solid street port on the intake. The exhaust porting can't happen if you have an NA unless you get the exhaust sleeves pressed out and replaced with turbo ones.

Light flywheel and balance

stay with 2mm seals. getting 3mm will require modding the rotors for $$$ or purchasing new rotors.

Better to figure out which class you want to compete in, then build the motor/car to fit the rules...



.

I guess more info like "hey what year is it?" would be nice. Car is 93 with PEP option, has 150,000 km and this is the original engine that expired. Im the second owner and have had the car for 15 years. Both rotor housings will be replaced, stock twin turbos rebuilt 70,000 km ago but still pulled strong. Keeping twins and the place doing the rebuild has lots of experience with stock to full race engines. Car class is ASP so engine mods won't change class.

Why don't you tell your shop (or us) the Power Range your shooting for and everyone can give you power and reliability info to keep you putting down XXX hp for the years to come.
:) Always set a goal. That way everything runs in synchronization. Oh yea if you decide you want 350, just keep in mind that in 3 years you might want 500. So just calculate based on that theory. For example say 550 injectors are proper for x hp set up. in 3 years you might want xx hp and you need 720. so instead of buying then selling the 550's get 720's. I just always try and plan for the future.

ditto on figuring which class. Best thing is to read the rule book for whatever autoX series you want to run and build to the rules. Better to be fast in class...

i wish we had autocross here still its a little over an hour worth of driving to get to a half ass event much less a really well run event

FWIW, my goals and use of my car are very close to yours. I did my own rebuild a few years ago with guidance from an experienced member...he also recommended staying with stock two-piece seals for my new housings.
You don't tend to live above 7k rpm for extended periods in Autocross. As long as the rotors aren't out of spec, I'm not really seeing a reason to balance the engine.
IIRC, there were differing schools of thought for lightened flywheels in autocross, but maybe that depends on exactly how lightened you go.


FREE:
*Double throttle removal
*Remove AWS
*With the PFC I'd remove emissions if you don't have testing. That eliminates about half the vacuum lines and solenoids....simpification.
*Retain stock pulleys

COST:
*Quality street port...intake and clean up the exhaust
*Clean and flow-test injectors
*Replace or delete Fuel Pulsation Damper
*New coil harness (easy to do during re-assembly/re-install)
*New plug wires (see above)
*Hi-flow cat...I like Bonez
*Heat coat and/or header-wrap the downpipe. If your really feeling flush, heat-coat the exhaust manifold for the turbos.
*Aftermarket motor mounts.
*Replacement OMP lines...either stainless or new OEM. But personally I wouldn't try to reuse them if they're 20 yrs old.
*Oil pan brace
*If you have a Touring/Base, consider a used set of dual oil coolers from an R model.
*If you're able to delete emissions, get an idler pulley to replace the air-pump. There are at least three sources for them. Search in the 3rd Gen. section. Keeps full belt contact on water pump...important in autocross.
*Replace the clutch fork. They've been known to fatique and break with age, especially with stiffer pressure plates. While it's off I'd also replace the throw-out and pilot bearings too.
*If it's not been done previously, replace the OEM wax-thermopellet with the metal plug. Available for next to nothing from Pineapple and some others sources.

*A simple boost activated AI system for cooling, knock suppression and carbon control (Check the SCCA book though, this may not be allowed in ASP)

Sorry, but you were discussing porting the engine. Porting is not allowed in Street Prepared classes, which is why I advised you as I did. :icon_tup:

^Which IMHO seems a little inconsistent, since IIRC cam timing/duration can be changed on a piston engine.

On a positive note....checking an old rule book... "F. Intake water injection systems are allowed".

Yeah, I would love to do a little porting to even things out with the other cars in my class. But alas, I have to make due with light weight and superior skills. :)

As long as the course is tight, I can beat damn near anything on four wheels. But give them just a bit of a straight section to put their horsepower to use, and it turns into a very desperate battle. Either way, I love the challenge of taking on the Corvettes, Porsches, and the occasional supercharged Miata. :)

I have/had a great time too. But honestly I'm the limiting factor at events...not the car.
Hopefully I get in front of tuition costs for my kids in the next year. Then get some lessons and a dedicated set of 'R' compounds instead of PAX. I hate PAX.

Thanks for all the pointers,

Kentetsu - you are correct, no porting allowed, thanks for the heads up, will ask for port matching and surfacing which is allowed.

PiginaBlanket - I agree having an end goal is a good idea, my idea was max 350HP so most things can be stock, injectors, turbo, etc. Having the car for almost 15 years I think I'll be happy with that level of power.

Sgtblue - The car has to make it though AirCare(smog) so I have to leave emissions intact for now, almost everything you listed will be replaced.
*Quality street port...intake and clean up the exhaust
Port matching as per SCCA rules
*Clean and flow-test injectors
Ordered replacements off ebay (Used ones will be cleaned and flow-tested, if bad have a line on new ones available $$$)
*Replace or delete Fuel Pulsation Damper
Replaced
*New coil harness (easy to do during re-assembly/re-install)
Replaced
*New plug wires (see above)
Replaced
*Hi-flow cat...I like Bonez
Have RB dual tip cat-back and FEED down pipe
*Heat coat and/or header-wrap the downpipe. If your really feeling flush, heat-coat the exhaust manifold for the turbos.
Maybe
*Aftermarket motor mounts.
Will order some
*Replacement OMP lines...either stainless or new OEM. But personally I wouldn't try to reuse them if they're 20 yrs old.
Replaced
*Oil pan brace
Have one to be installed
*If you have a Touring/Base, consider a used set of dual oil coolers from an R model.
Wish list item
*If you're able to delete emissions, get an idler pulley to replace the air-pump. There are at least three sources for them. Search in the 3rd Gen. section. Keeps full belt contact on water pump...important in autocross.
AirCare Boooo
*Replace the clutch fork. They've been known to fatigue and break with age, especially with stiffer pressure plates. While it's off I'd also replace the throw-out and pilot bearings too.
Have bearings with clutch kit, will order new fork
*If it's not been done previously, replace the OEM wax-thermopellet with the metal plug. Available for next to nothing from Pineapple and some others sources.
Replaced
*A simple boost activated AI system for cooling, knock suppression and carbon control (Check the SCCA book though, this may not be allowed in ASP)
Not allowed

The tear down, only one apex seal was left intact all others had broken tips, front rotor eat a seal and carved rotor and housing. So two new rotor housings and one new rotor (letter matched). One of the turbos ate some apex seal bits and is leaking oil from many places so the shop has a good turbo that will be rebuilt and balanced. Since the flywheel and counter weight are being replaced as well as a rotor that's why I thought to have it balanced, to many new variables. Side plates are all good will no visible wear.

Other items to be replaced, new high boost 2mm apex seals, solid corner seals, water pump, lots of nuts and bolts, seals, hoses, etc......

Again thanks for your input

??? I've only got the 2007 rule book saved at the work computer, so maybe they're changed that. But in the old book section 15.10 (Street Prepared Category) sub-section F specifically allows it....
And water is all you need. I used to see big swings in engine coolant temps after periods of hard boost... i.e. running the course. Since I added AI there's virtually no movement. And knock levels were reduced too.

Even with emissions I think you could still delete the double throttle and AWS if you still have them. It would have to be a pretty sharp-eyed visual inspection with a mirror to spot either if done properly. And neither would affect actual testing.

Regardless, good luck with everything. Give us some updates when you can.