Hey guys i've got a 2002 f4i and i'm looking to turbo that bad bitch. Right now i'm designing an intake manifold for it and i've got that all covered. As far as cams go, i'm still doing research on how i can increase the volumetric efficiency in an n/a trim, and i'll adjust lift as needed for the greater flow requirements of a turbo.

Basically what i'm asking is, has anyone done this before? I'm either going to be running a gt12 or gt15v. I have to run the intake through a restrictor so i'm not exactly sure how much boost i can efficiently pump through.

How do internals of an f4i hold up to boost, and how much boost can they safely handle? Do they make internals that are designed for turbo's? I'm going to keep the cylinder pressures up to match a dynamic compression ratio of about 10:1. Due to the restrictor that i'm running, my static comp in n/a trim is over 13:1, but the restrictor kills my volumetric efficiency so much that my cylinder pressures match like a 9.5:1.

I don't mind upgrading internals, or designing my own to be machined, but tha'd be a big bitch if i have to resleve the block.

 

oh ya, anyone know a place that can coat internals with like a nitride coating? Or anything to help disperse heat and prevent hot spots?

 

I'm guessing that this is for an SAE car? Since you mentioned restrictor.

SwainTech (if they're still around) does coating work on internals. You should be fine with the stock cams, you're not going to pick up that much, and you're pretty limited in whats out there (nothing for a turbo application in a F4i) so I'd leave that alone. As for lowering comp, contact cometic and have them make you a HG to lower you down to whatever you want to be at. Don't look at it from a volumetric standpoint, 13:1 with boost is too much... You gotta lower it down, I also suggest o-ringing the motor/head.

I was running 8psi through a carbon restrictor on our R6 motor when I was in college, use a thicker HG to lower comp from 13.5:1 down to about 11:1... the problem with SAE is that they make the restrictor even smaller for turbo cars, so really you end up with the same performance of a properly tuned NA car.... my senior year, we switched to NA.

 

Nah the restrictor for an N/A engine is the same for any supercharged or tubro'd engine. BUT if i decide to run E85 fuel, my restrictor has to be 1 mm smaller, which i may do if i use a turbo. I'm not quite sure 93 or 100 octane will cut it as well as E85.

 

If this is your first time as the engine group leader do not turbo your motor. You're going to have plenty of issues to work out like designing a reliable cooling system, intake and exhaust tuning, and getting a dyno program put together. If this has already been done (and done well) and you have the additional personnel to manage the other components of the engine group...which means you have an established engine package then go for it. Just keep in mind that the fastest cars typically are not the most powerful. That surge of torque is pretty awesome.

I know a couple of teams have used GT-15s and at least one team that ran a GT-25 but switched to a GT-20 before competition Formula Student.

 

Well as far as turbo's go i'm pretty experienced having put together a full custom kit on my 240sx about 5 years ago. I feel confident that if i can maintain 1atm absolute in the intake manifold that i could make the stock f4i 110 hp as long as everything else is designed right.

THe cooling system is already designed and has been crazy reliable in the past. I think the most important thing is having access to sufficient dyno tuning if a turbo is used.

BTW this is still all conceptual, I'm still not sure weather or not we will use a 4 cyl, we may use a 1cyl from an ATV, or a 2cyl. Just trying to gather as much info as i can...