So I'm building a turbo motor for my '91 325ic, well buying a partially assembled one!
Anyway, here is the setup for the motor/turbo:
2.8L M20 (524td crank)
M20 rods, profiled and shot peened
8:1 Ross forged pistons
all balanced
Head will be rebuilt with new goodies, light port work, water passages welded
Raceware studs
Cometic MLS gasket
Turbo is a T4 unit from TCD with the following specs:
AR .58, P trim, GT35R wheel
TCD log manifold
So, I'm looking for an appropriate turbo cam to maximize the setup. Suggestions?
As for the injectors, I feel like this engine will have no problem approaching 400hp @ Crank on pump gas.
But I would like to build in the additional fuel system overhead to run E85 later down the road (it's not widely available in my area yet, so 35 mile round trips for fuel seems dumb).
So I'm thinking in reality I need injectors in the 50-60lb/hr area? Am I way off, close?
Have you talked to Todd at TCD for cam recommendations? He's pretty sharp on this stuff.
z31maniac wrote:
So I'm thinking in reality I need injectors in the 50-60lb/hr area? Am I way off, close?
A 3.2L NA motor making 300+ wHP with as much cam as I can push w/o overlap makes due with 24lb/hr at 60% duty cycle so I am thinking that 50-60 is too much and you will lose some fine tuning control.
DISCLAIMER I am not a turbo guy - just noting that you are looking at over 100% increase in flow capacity over what I run at 60% capacity to generate 80% of your target.
So, I'm looking for an appropriate turbo cam to maximize the setup. Suggestions?
Don't believe the turbo cam nonsense. It's marketing BS, and nothing more, just like the special nitrous cams, when it got popular. Neither should you buy into the talk of overlap, and boost blowing out the exhaust.
Cam (duration) for your intended RPM range, and get as much lift in as is reasonable.
Giant Purple Snorklewacker wrote:
z31maniac wrote:
So I'm thinking in reality I need injectors in the 50-60lb/hr area? Am I way off, close?
A 3.2L NA motor making 300+ wHP with as much cam as I can push w/o overlap makes due with 24lb/hr at 60% duty cycle so I am thinking that 50-60 is too much and you will lose some fine tuning control.
*DISCLAIMER* I am not a turbo guy - just noting that you are looking at over 100% increase in flow capacity over what I run at 60% capacity to generate 80% of your target.
Did you read the part about future use with E85?
From my understanding, you need 30-40% more capacity to run E85 than normal "E10."
z31maniac wrote:
Did you read the part about future use with E85?
OK, no... I didn't see that and for the most part - I am out of my depth so I'll just pipe down.
^ I am too! Hence the thread!
stuart, no I haven't emailed Todd yet. I like to try to have some level of understanding of what I'm dealing with before I bug people who are trying to make a living.
Zomby Woof, interesting. I'm not knowledgable enough about to agree/refute you. I've got the most basic understanding when it comes to more lift/duration = more fuel/air in.
As far as, overlap, timing of opening/closing valves in relation to RPM/piston location within the stroke, etc. Might as well be electricity, because it's all magic.
6 cyls are easy to calculate fuel injectors for. Just take desired HP and add CC's to the end. Add 30% to give your self some room for safety. example, if you use 450cc dsm injectors, you can run 450hp at the flywheel safely. Ive seen some people run 450Whp with that much less margin of safety.
So if you want 400BHP, get some 450cc injectors. 550's are easy to find from FC rx7's I believe, also newer evos have 560cc injectors, so those are good to run, as they are designed to idle and have nice drive ability.
For E85 you'll need to add 30%ish of course. But also, a GT35 compressor can do 600HPish and if that particular turbo can do more you should try to match that. That puts you in the 700-800cc territory easily.
Take a look at IDC1000's and IDC2200's (or is it just ID?) they are the newest generation of injectors and the 2200's are completely driveable and can hold a perfect idle. But that also depends on your engine management, I'm not sure if an 80's ecu chipped has enough resolution/computing power to use them. My friend with a 600HP KA24DET in his 240sx is using ID2200's with an AEM standalone, it'll be a pump gas daily driver.
~Alex
I'd suggest using the RC Engineering injector calculator for this one, then do your E85 percentage afterwards.
Zomby Woof is pretty much on the right track as far as cam, but duration does have an effect on turbo motors. Cam for turbo useage =! cam for n/a usage.
That said.... for 400hp on that motor, with that turbo, i'm unsure if you'd even need a cam.
^It's not about "needing" a cam, it's about getting the most out of the entire system. I have a seriously built M20, with a good turbo, going standalone EMS..........to not put in a bumpstick to optimize it seems, well, lazy.
Rustspecs13, thanks for the links. However, I was hoping someone could point toward something a bit more affordable, like a used OEM injector. Like the EVO injectors you mentioned.
$700+ for 6 injectors is not exactly what I was thinking of.
I've got a good set of 30lb/hr injectors that is coming with my turbo stuff, but that's not anywhere close to what the rest of the package will be able to handle.
Might try to track down a few RX7 secondary injectors. They're big. 
I hear you on the cam, i just saw "400hp goal" and you don't need a cam for that.
z31maniac wrote:
^It's not about "needing" a cam, it's about getting the most out of the entire system. I have a seriously built M20, with a good turbo, going standalone EMS..........to not put in a bumpstick to optimize it seems, well, lazy.
You are correct in thinking that way. Unless the stock cams are something substantial, they really have no place in a performance setup. Performance is generally why people install turbos. Unfortunately, cams are often an afterthought, and should be one of the first things done as part of the build up.
Low lift, and short duration will be seen by the turbo as a restriction. A kind of restrictor plate, really. Add an appropriate amount of duration, and lift, you make more power, on less boost, and less heat. Not only that, but it will spool faster, pull harder, and rev more freely. It's all about the package.
92CelicaHalfTrac wrote:
I hear you on the cam, i just saw "400hp goal" and you don't need a cam for that.
Yes, but like ZW said, a better breathing cam (needed on the fact the engine has increased in displacement with head work anyway), will allow better spooling, and more HP on less psi, etc etc.
400hp isn't necessarily "the goal," 400hp RELIABLY is the goal.
That's part of why I want to optimize the entire package as a whole, instead of doing some RRFPR hack job of a turbo install. No good to stomp an E92 M3 on the highway, only to be broken down at the next off-ramp.
I'm thinking E85 would get into "plaid" levels of acceleration in this car.
^Completely understood, and that's why i've got a "spare" complete head with a nasty cam for my car as well.
Work smarter, not harder. Cam applies.
And yes... you should be seeing plaid. 
