I have a Drag III turbo kit, turbonetics t3/4 (57 trim, 63 exhaust), tial wastegate, thermal 3" exhaust and 3" cat, act clutch, 9:1 je pistons, eagle rods and new valves. My question is what's the safe max boost I can with stock fuel and ignition setup. I only have the inline pump that came with Drag III and I also have the 7 range NGK plugs, but that's it.


Thanks!

 

Uhmm... do you have the FMU from the drag kit installed?

If you have the FMU, you can boost 7psi max safely.

If you do not have the FMU, you can boost 0psi max safely.

Dustin

 

I do have the FMU. 7 psi??? That's how much I ran with my stock internals and 10.6:1 compression. Can I have some other opinions on this?

 

Your engine can handle plenty more boost, it's your fuel system that's holding you back. At 7psi your fuel pressure is over 120psi and I'm sure your fuel injectors aren't very happy about that.

 

Hehe, you think I'm wrong?

Well go for it then, try 25 psi and see how she holds.

The motor isn't the weak point -- it's your fuel system or lack thereof.

Dustin

 

Stock injectors + boost is not your friend, regardless of compression ratio. Don't half-*** it. You already spent the money to build the engine, now get some engine management and feed it right!

Sonny

 

Yes, his point is - the drag fuel pump and FMU simply will NOT deliver enough fuel to run more than 7 psi safely for any length of time. You will lean out, and leaning out will cause detonation. Lower compression won't help when your A/F ratio is too high. You can always retard the spark waaaaay back to put off detonation a little longer, but then you're just throwing away the power you would be gaining from the increased boost.

 

Wrong. THe FMU will provide the fuel needed on any account just as long as the correct disc is working in coordination with the injectors.

The weak link in the setup is the stock 240cc injectors. Get some bigger ones, like 450's and you should be able to boost as high as your tuning skills provide.

 

Disagree. Do you know how many motors I have seen grenade from high speed runs with the FMU? Granted these people are running stock ecus with very aggressive timing -- But when injectors have to open against 120psi+ of fuel pressure (when honda rates them only to 60psi) they get VERY hot and pull a lot of amperage. The result? Unreliable fuel delivery. The FMU method is never safe...

Dustin

 

Cool thanks guys. I tried it at 10psi for a day (I used to run 5psi for several months) and all I could say was WOW! Now I tuned it down to 8psi. Just smoked a WRX on the way home..hehe

If I get bigger injectors, say 370cc or a little higher, do I need to get some kind of fuel management or will my stock ecu handle that? Also, should I get a better intank pump, and how about the FMU?

 

You will need a smaller disk with those injectors, and I dont think that your stock ecu will idle those puppies. You could use an afc to idle them, and use a 8:1 or 6:1 fmu disk (someone correct me if I am wrong).....but really you should look into a standalone. I think that wayyyyy too many people build a motor and forget about the fuel delivery, or try to get around it by not spending the cash. If you want to boost safely you need to spend the money. There is not really any way around it. Get a walboro intank pump or a pump out of a mitsu GSX.

 

OK, so which disc is it that I should get?