Author Topic: Turbo done right....300hp? (Read 6563 times)

kevins08 · « **on:** April 27, 2009, 03:26:24 PM »

hello all. i have been readin and researching for a long time now and finally am about to delve into the project. i have a 1974 2002 and it will be gettin a m42 swap this summer and the motor buildup is beginning. it i will be turbo'd and im shooting for about 300hp to the wheels (hope i dont get disapointed). here's how it's going down, please offer any help and suggestions that you can/want to!!! especially on CR and specifics and such!

forged rods: M50 rods(Eagle)
Forged pistons: 8:5:1 or 9:1 CR (from either wiseco or je)
RRFPR: suggestions here, what do you recomend?
Management: Megasquirt
Turbo: 16g from mitsu evo then replace with garrett gt28-series (20-25psi)
Intercooler: Mishimutu
Manifold: Custom tubular

thats all i can think of right now, im forgetting stuff i know. feel free to comment and suggest though please!!!

strypt · « **Reply #1 on:** April 28, 2009, 01:03:31 AM »

Both CR you have listed will run fine (What quality fuel do you have where you live?) But the M50 rods are 5mm shorter, do the pistons have that 5mm extra in compression height? Otherwise your CR will be very low.

No need a RRFPR with a standalone ECU, go with bigger injectors. You will need them anyway to reach 300 whp. You'll also need a bigger fuelpump.

kevins08 · « **Reply #2 on:** April 28, 2009, 01:28:29 AM »

oh yes. 42 or 48lbs injectors will be used.....

the pistons will be custom, so that will not be a problem. also, i didnt realize the shorter rods, but now that you mention it i think i remember this being used with the diesel crank correct? in that case ill either have the pistons extended that 5mm or ill just get custom rods as well, ill see how prices compare...

rob_e30 · « **Reply #3 on:** April 28, 2009, 01:36:54 PM »

I think your numbers are obtainable, but I'm not a fan at all of a RRFPR. If you size the injectors properly and have the right ECU, you should not need a RRFPR. They are tough to tune and hard on your fuel system. I built a turbo Miata at one point and was running up to 100psi on the rail. That's a bit scary.

Stock rods from an M42 can handle the boost but with the rod length on a stroker crank you do get cylinder thrust wear.

kevins08 · « **Reply #4 on:** April 28, 2009, 02:52:29 PM »

im not running the diesel crank, just stock crank. so are you saying i really only need the new pistons. i will also obviously be getting new head gasket/head studs etc. as well.

i guess i didnt realize that i dont need a RRFPR, so i wont have one i guess. do you think 42lb injectors will be sufficient or not? what would you recomend?

rob_e30 · « **Reply #5 on:** April 28, 2009, 04:12:26 PM »

As far as injector selection there are a number of variables. I use the RC Engineering calculator to pick the proper injector. I would simply run custom pistons if I were you. We've had the stock rods over 45psi of boost (way over, but we don't know how far) without a problem.

Don't take this the wrong way, but I think you need to do some more homework around the fundamentals of FI before you go too much farther. The decision to run a RRFPR is a function of your ECU's ability to understand how much fuel is necessary based on the amount of air being forced into the cylinders. A RRFPR tries to match increased fuel need with increased air pressure in a pretty linear fashion. Because these engines were made with an AFM the assumption in the ECU is always based on 1 atmosphere of pressure (or less) and the range of compensation in the injector duty cycle is fairly narrow.

I recommend reading "Maximum Boost" by Corky Bell and doing a lot of research. I had previously built a turbo project before starting the race car engine (that engine went through 2 iterations of ECU), and I still took 6 months to figure out what the best way to go was.

kevins08 · « **Reply #6 on:** April 28, 2009, 05:28:23 PM »

im actually in the middle of reading it right now actually.....

i have a moderate understanding of everything, and to be honest the RRFPR was one thing that really boggled my mind and i didnt understand it. i thought that using the right injectors, fuel management, etc. would be fine, but then i read about it everytime ive read a thread on turboing an m42 so i was confused.

Boosted E30 · « **Reply #7 on:** April 28, 2009, 09:40:52 PM »

For engine set up i would just do pistons gasket and studs for around 8.5cr and you will be close to 300whp for sure with the proper tune on your desired boost. im running 42lb injectors they should be good for around 300whp im told. im making 232whp on 10psi with this discibed set up and there is definatly room for more just not sure if the injectors are big enough. But i think once you have it running you will find close to 300whp in a 2002 will be plenty fun.

rob_e30 · « **Reply #8 on:** April 28, 2009, 11:32:16 PM »

Quote from: kevins08;71034

im actually in the middle of reading it right now actually.....

i have a moderate understanding of everything, and to be honest the RRFPR was one thing that really boggled my mind and i didnt understand it. i thought that using the right injectors, fuel management, etc. would be fine, but then i read about it everytime ive read a thread on turboing an m42 so i was confused.

It's good that you are reading it. Keep in mind that everything is interconnected. Injectors are a function of boost level, fuel pressure and the ECU's ability to calculate the proper AFR; ECU dictates how air is measured (or not), how much control you have over spark timing (or not), and how adaptable the spark and fuel is to AFR's (or not). You are touching every system in the car and everything is a trade off at one point or another.

As far as a RRFPR goes, it tries to keep the fuel in the proper ratio to the air (boost level) by raising the fuel pressure as the boost level goes up. Your best bet is to run a MAP sensor along with a wideband O2 sensor and a knock sensor. That allows you to calculate timing and fuel based on the real air pressure in the manifold, the real time AFR's, and the presence or absence of knock.

Bunta · « **Reply #9 on:** May 02, 2009, 11:09:02 AM »

Im still planning a similar build.
I think im going to go with the m47 crank, 135mm pauter rods and a set of forged CP pistons. I want 8.5cr and am honestly baseing my project alot off this one.

http://r3vlimited.com/board/showthread.php?t=84137

It has everything I want besides the water to air intercooler.
Hes making 308 at the wheels @ 15psi not sure with meth or not.
The engine management is what scares me most. On mine I plann on installing it on the stock car first, getting it running and tunable then let me learn the ropes before I put my fresh turbo motor in.
Still not sure on what EMS ill use. Megasquirt is appealing but running my big money motor on a $600 DIY EMS makes me a bit nervous. In a perfect world id have KMS or Tec3 or Motec soooo many options.
Then ill get it professionally tuned or if I get good enought do it my self but you really need dyno time.
Hope this helps.

Hunter