So the tc is up and running, for the most part all is good. I have been slowly upping the boost and I can now hit 15-16 with the stock exhaust still on the car, boost gauge recorded 20psi if i open the cutout.

Problem is i am murdering the 700cc injectors with 100% duty cycle at only 14psi so i can't really boost above 12ish to be safe. Do you guys think I will be able to run 20psi with just a return fuel system or will it take even bigger injectors?

I think around 12psi 5000-6000 rpm the duty cyle is 75ish, but then as boost climbs above 12psi it looks like the duty cycles shoot up in the blink of an eye to 99-100.

 

20 psi i think is achievable on return setup but will be in high duty cycles.. 900 or 1000 will give you plenty of room

 

It seems crazy that this little engine needs 700cc just to do what its going now. But surprisingly the fuel economy is still better than my is350 lol. Damn, just upgraded to 700cc from 550, I need to find some pnp big flow injectors now.

 

well you are looking at moderately high boost on a big turbo.. dezod 850 pnp or ptuning 900s are good for what you need

 

Yea sounds like the way to go, I think I will do the return fuel for now and wait a while on the injectors. Anyone know if the dezod intercooler can do 20psi ?

 

Im running the dezod intercooler with 60-1 on 19psi and its been great. My IAT's are within 10-20*F of ambient after multiple pulls on the highway. My MAF is blowthrough, so Im logging IAT using ScanXL. Of course it gets a little higher in stop and go traffic, but I dont see a larger intercooler helping this much. For its size, the Dezod intercooler is very efficient

Oh forgot to mention - Im on E85 and built bottom end, dont think it would have much affect on IAT pre throttle body, but wanted to make sure I mentioned it

 

Thanks for the info, I think I may eventually play with e85, but for now I have to see how things go with regular gasoline. I know when boost shot up to 19-20 I couldn't hook up in 3rd. Good to know that the dezod i/c can handle the 20psi though, i've got a comp 57trim .68a/r so i'm guessing your 60-1 is a bit bigger? I am going to be running blow through soon also, and upgrading to a 3" intake pipe on the inlet of the turbo.

 

Yea 60-1 is slightly larger - Im also running the .70 ar compressor housing which is like a 4" intake / 2.5" out. I found out I can hook in 3rd if I ease the throttle in so it gets past peak tq without making full boost lol With my blowthru setup, I dont even have an intake just a 4" cone filter on the turbo

 

I would say pick up some 900s. A return system is useful, but the cycles will still be high. You will have more room to mess around with the injectors then you would the return system. We all seem to want MOAR boost

 

Using a return setup with a boost referenced regulator will make the largest difference. As of now you are stuck using the regulator in the tank. Which gets over ridden fast and holds one pressure. For each lb of boost you create you need to increase the fuel pressure by 1 psi. This maintains a static fuel pressure then. So if you start at 43.5 psi of fuel pressure and you add 20 psi of boost if you have not increased the fuel pressure you are effectively subtracting that from the boost. You would have a net fuel pressure of 23.5 psi.

This is why you have to run such high duty cycles.

Return fuel system with a proper regulator will solve all of your problems.

You will also probably see more power from less boost because of more accurate fuel delivery.

 

don said it well. Boost pressure is like fighting against fuel pressure, more boost more pressure keeping fueling from coming out of the injectors. Also a bad quality atomization

 

with 700's, return system and wallbro i was at i think 60% dc at 16psi.....return systems are well worth the penny.

 

It's like riding your bicycle into the wind. You have to pedal harder.

 

Thanks for the insight Don, that makes much more sense now. It looks like this problem is already solved ;)