coldy13

Makes it go fast as hell!!!!


My car is finally completely finished and running good. I am still putting on MSD Ignition in a couple weeks, but it's not really needed. The only problem I'm having now is boost creep. The wastegate spring is for 7.5psi, and the wastegate is ported as much as it can be. But past 5k RPM, the boost just creeps all the way up to 14psi. The engine is easily taking the abuse, but I don't know how long it will last. The engine is completely stock internals, 140k miles, still has perfect compression though.

I'll put up finished pics of it in a couple days, and maybe some video if I get the chance

NanaimoRx-7

Wow man, wow. 14 psi....aren't you non-intercooled?

EDIT: Oh and video, please

WackyRotary

Watch out for cracking dowl areas. Check under the oil filter mount and the area between the 12a symbol on the front rotor housing were it mates to the front endplate. Doesn't take much to have that happen. I know, it happened to me getting too ambitious with my boost controler. The fix is to replace the endplates with fresh ones and limit boost a little better.

Also, I'd be VERY cautious with a engine known to have that many miles on it. The apex seals are very thin at that point, and doesn't take much to put them out of service. I bought a stock 12a once and it lasted a week on the boost with it set at 7psi.

My streetport with low mile apex seals runs great though, yet!

12abridgeport

Also too much boost can pop your oil o-ring, usually in the rear rotor. You would know that happened if you see a lot of oil coming out from in-between rear rotor housing and end plate, happened to me before.

coldy13

Yep, no intercooler yet, but right now it's 35deg outside, so my intake temps are still cold I'm trying to see if I can get rid of the boost creep, so I can actually set how much boost I want to run with my boost controller, but no luck yet.

wwilliam54

i dont see long engine life for you

coldy13

Either do I, that's why I'll be building a street port 12a with low comp rotors later for when this one blows. But first, I have to find a cheap 7 for me to use as a daily driver, my turbo only gets 10mpg.

seanrot

iTrader: (2)

Hey coldy,

I just went to your cardomain site that bragging rights 13.8s 1/4 and a 5.5s 0-60 is that in this car/setup? If it is I cant wait to get mine up and running...

WackyRotary

Well just for comparison sake, I have 14.13@98mph for my S4 turbo'd streetport 12a. This with 2.3sec 60ft times which is horrible because of excess wheelspin-which is difficult to manage because too little throttling results in boggin, and too much has the same effect on overall acceration with it just spinning the street tires- 205 R14's.

My turbo is kinda "peaky" for some reason. I don't use the dynamic flapper the S4 turbo comes with and the twin scroll is port matched to the same size, ported wastegate, no issues AT ALL with boost creep.

Coldy, you should take your turbo off, and wield a larger flapper on the wastegate, and port the hole larger, that is how I overcome boost creep.

coldy13

Those are just estimates, I havn't gotten the chance yet to get any real times.

Sudox_E

coldy, youre getting 10mpg? Thats gotta hurt the wallet! I hope I get a little bit more when my setup is done, but we're jsut gonna have to see

680RWHP12A

you will get **** mileage but the nice thing with a blow through carb setup you wont run out of injector and blow up!!!! (LOL efi guys)

as long as your timing is conservative and you have lots of fuel its going to be hard to blow it up.... you gotta love that ROTARYSHACK carb tuning !!!

Directfreak

iTrader: (2)

What exhaust are you running?

That is ALOT if Boost Creep.

680RWHP12A

he is running 3" from the turbo to the muffler

Directfreak

iTrader: (2)

Maybe a 2.5 in would've been better for him. Too bad those stock Wastegates are so tiny. They creep even on stock TII's

pillage6

Hey Robert, I am thinking of running 14 lbs. consistently, is there something I can do to an IDF to keep it from blowing apart?

Or will it be okay?

Sorry to jack the thread, but my motor is a 13B 4-port that is stock, so I guess it pertains.

coldy13

Actually, it's 2.5'' stainless, all mandriel bends, moroso spiral flow presilencer, apex'i n1 style rear muffler, run under the axel. It probably flows better than a lot of 3" setups because of the mufflers I used.

coldy13

I ported the stock wastegate as big as it will go.

Junia

What kind of boost controller are you using. Have you thought about using something like the Blitz SBC or something similar.

eddierotary

iTrader: (7)

what turbo you have? a S4,S5 or custom?

riffraff

ehh. if you know what you are doing, that it not that much.. i knew a guy who used to run 25-30 psi through his 12a.

pillage6

For how long though?

Was it a rebuilt motor or stock?

ToyotaryatGR

there is an easier fix for that it's called pining your engine it's not cheap but it saves your engine. the way it works is a machine shop will drill your engine plates so that you can put dowel pins through more holes than the stock ones if you need more info pm me I do them at my shop.

coldy13

My dad is foreman at a very big machine shop, so when I rebuild and street-port the next engine, I will be dowel-pinning it. But that won't be for a while.

coldy13

S4 turbo.

I have tried it with no boost controller, just a straight line to the wastegate, and with the manual boost controller mounted in the cabin, and there is no difference.