Turbo Build ~300-350whp goal

[cpeehler7]

So, I haven't been on this forum in too long. I've had my black STC autocross GSR on here a few times, but after taking a quick ride in a friends Civic Si pushing about 340whp ~200 torque I decided I need to boost the integra hahah. So that said, I do have most of it all planned out, my co-driver for autocross/rallyx has built plenty of B series and D series motors and knows his stuff. I just want to do a little extra research on my own and pick some of your brains to see how exactly I want to go about this. As of now the GSR's motor is stock, I'm going to be racing his SMF autocross car next year for the pro-solo series, so I'm willing to make this car "stupid" and not fit into any class for autocross because I have his car to drive (which is nationally competitive).

So it's going to be a budget build. We are rebuilding the motor soon for the autocross season, replacing the clutch with an Action 1ms Stage 4 6 puck clutch, and I went with a ACT street flywheel. Weighs in at 12.2, wanted something lighter, but streetable. Not a fan of the <9lb flywheels they're too jumpy for the street imo, cool for the track, but a bit uncomfortable for daily driving.

I'm not exactly sure what turbo I'm going to buy, I'm kind of leaning toward picking up a used one to rebuild, or a used on in working shape. We should already have injectors, BOV, and wastegate sitting around the shop. I'll have to pick up a new exhaust manifold and an intercooler. I was looking at one of those smaller mishimoto intercoolers, those seem to be pretty popular and get the job done (correct me if I'm wrong). Also, not exactly sure if a half radiator would be necessary to free up space, guys who have done this before should know. If so, let me know!

Now one of my big questions is about getting power down to the road. I'm assuming the open diff on my car would be pretty good at laying down 1 big streak mark on the road. I probably need to buy an LSD. This car is mainly going to be a street driven car, I may take it to the track occasionally, but I don't want a twin clutch diff or anything moderately unstreetable. I'll probably end up buying wider wheels in the future maybe some 15x7 or 15x8 wheels, as of right now the wides tires I can run are the 205/50/R15 Direzza ZIIs. Decent tire, could be wider, but it is what it is for now. If I do end up hitting the track up, I may get some Toyo Proxes RR, but for now I'll keep it affordable with ZIIs.

I know I left a bit out, just looking for a little advice here. Mainly advice on a good LSD that's not like $800. I just have a feeling a car pushing 300+ to the wheels is going to need a better diff than the open one that's in there. The good news for me is, that my co-driver has the knowledge, the tools, and a dyno. So no I'm not trying to be a cheap ass who is going to boost a car then try to ask if it will be okay without a dyno tune... He'll probably hook me up with some stupid cheap labor because I let him beat the s*** out of my cars though lol. It's worth it though, I get to learn a lot. That's what I'm aiming for, still pretty new at this, but gotta start somewhere...

Oh also, what sort of things are worth upgrading to make the build more reliable. Motor and trans will be out of the car, the only thing I can think of would be ARP head studs. Other suggestions welcome.

 

[Nick_C78]

If you don't want to spend 800 on the diff you can only get an OEM ITR diff. That being said...you should get the Type R transmission as a whole. The gearing is sexy and comes with OEM LSD. They go for around 900-1200, which is suuuuper tiny for the benefits it gives. Don't underestimate gearing.

 

[cpeehler7]

If you don't want to spend 800 on the diff you can only get an OEM ITR diff. That being said...you should get the Type R transmission as a whole. The gearing is sexy and comes with OEM LSD. They go for around 900-1200, which is suuuuper tiny for the benefits it gives. Don't underestimate gearing.

That is a good point. I know the ITR trans is much better for racing, I just can't justify spending that much on a transmission when my current one has nothing wrong with it. From what I've heard though, the itr trans is worse as a DD, shorter gearing, higher revs on the highway wouldn't be the best for me. It's possible that my co-driver knows some guys with used diffs. I'm kind of leaning toward picking up a used ITR diff, or if there are any other good streetable diffs that you know of I'll keep an eye out for those as well.

 

[Nick_C78]

You know you can sell your current trans to offset the cost of buying the ITR. Just a thought. It isn't that bad for DDing. People exaggerate it. Especially if you get the 97 JDM Itr trans. Has the 4.4 Final drive vs the 4.7 in the new JDM ones and USDM ones. You could also swap out the 5th gear in the ITR trans with the 5th from the GSR trans then sell the GSR trans. Best of both worlds.

I would rather spend 1000 on a complete trans and sell my current for 300-500 (Making total cost 500-700) vs spend 300 on a diff, that will also need shims and diff bearings to fit the GSR case. Out the door cost for installing itr diff in gsr trans will be like 550ish assuming you get it for 300 which is what I always see them sell for.

 

[cpeehler7]

You know you can sell your current trans to offset the cost of buying the ITR. Just a thought. It isn't that bad for DDing. People exaggerate it. Especially if you get the 97 JDM Itr trans. Has the 4.4 Final drive vs the 4.7 in the new JDM ones and USDM ones. You could also swap out the 5th gear in the ITR trans with the 5th from the GSR trans then sell the GSR trans. Best of both worlds.

I would rather spend 1000 on a complete trans and sell my current for 300-500 (Making total cost 500-700) vs spend 300 on a diff, that will also need shims and diff bearings to fit the GSR case. Out the door cost for installing itr diff in gsr trans will be like 550ish assuming you get it for 300 which is what I always see them sell for.

I'll think about it, it does seem pretty reasonable. Basically aside from the rebuild clutch/flywheel, I want the turbo build itself to be around $1000 in parts. So turbo, intercooler, any duct work, injectors etc. New trans I could justify spending a little more on, I do plan on making this more of a track car soon. There is a new 2.2 mile road course that's being built just over an hour away from me, so when that's finished late this summer I'll want to take the integra out there.

I do also have an 02 WRX, so if this car becomes slightly less practical as a DD, there is always my other car. Granted rallyx doesn't kill it... I'll start doing some more research, I've never been to a real track day. Just a year of autocross and rallycross. Did well this season, our rookie of the year, so I'd like to maybe get into SCCA club racing or track days this summer, or next. We'll see how it plays out, I'm supposed to be racing in the solo national/pro series next year so that should be pretty fun. This integra is a losing car for autocross no matter what class I go in, the civics are just lighter and more nimble in the same classes, there's no beating the 89 CRX Si in STC hahah. Those things are insane through the corners...

Thanks for the advice, I'll keep reading up and try to figure out where I'm going with this car. I just want something fun to track, that isn't going to cost a fortune. I don't want to be in this car like $10,000 then realize I dumped too much into it :lol: