Ok here is the deal guys. I'm have some tuning troubles with my new built engine. I can't seem to get enough fuel to keep from running lean. I'm running a stock 94+ 'teg fuel pump with 450cc DSM injectors. Also i've got a Zdyne Standalone with an FJO Wideband kit to monitor/adjust my A/F ratio. Before I built my engine I was able to run 10 Psi all the way to 8K, but that was pushing 95% duty cycle. Now i'm finding that on my new setup at 8psi i'm running again running a 90%+ duty cycle and still not able to keep the A/F ratios within an acceptable 12:1 A/F ratio. Now this suggests 2 things to me, the first being that my new setup is cable of making more power at a lower amount of boost than my previous setup and my fuel system just can't keep up. The second possiblity is that I have a problem in the fuel system itself that is causing it not to function properly.

The old setup was;

Stock block LS engine w/ GS-R girdle
Crower Top-end with custom cams(11.93mm lift/low duration) w/ P&P job
DRAG III turbo kit for a 94+ LS/Type-R
Zdyne SECU w/ FJO wideband and DSM 450cc injectors
94 integra fuel pump modded for the CRX wiring.
3" turbo back exhaust
XS Engineering MBC set to 10 PSI on a Tial WG -- This was the maximum boost my fuel setup would support.

The new setup:

84.5mm Darton sleeved LS block, Wiseco 8.8:1, Eagle rods, GS-R girdle
Same top-end as above
Same turbo as above
Same fuel setup as above
Same exhaust as above
XS Engineering MBC turned off, Tial WG hit's 8psi even though it's 7psi spring.


Any ideas, opinions, theories would be greatly appreciated.

 

^bump^ Need some ideas guys

Anyone know how I could lower the boost down to like 5~6psi, even though my WG spring is a 7psi spring? I don't guess I could take the spring out and run just off the MBC could I?


[Modified by Speed PHreak, 2:38 PM 12/15/2002]

 

dont take the spring out. that would render the wastegate useless. the only way to get it below the 7psi, is a different spring.

my friend has a 90 integra with a 84mm ls motor with a zdyne and a 57 trim t3/t4. he is running 720's and a stock pump. we did tuning up to 1 bar on the wideband and the fuel system was adequate for that.

so i say upgradet the pump or the injectors. the zdyne had no probs idling with 720 at all, and i think you can get a set quite cheap from viren.

 

also i noticed that you said that you are hitting 8 psi with a 7 psi spring. this is because of the drag manifold and the full 3 inch turbo back. you are getting a little creep. if you upgrade the manifold, you wont have this prob any more.

 

I agree, either upgrade the fuel pump or the injectors.

 

Upgrade both. Since you overbored your block, you should have more displacement and thus needing more fuel than your old setup.

 

I was initially gonna say you run out of fuel at 8psi because somewhere in your new set-up you gained compression via larger valves, maybe they resurfaced your head/block too much, running a thinner head gasket than before etc, etc. but then I look at your set-up and you've lowered your compression.

Then I was gonna say, make sure you're running the same fuel pressure as you did before...could there be some reason your FPR is not calibrated the same as before and are now running it at a lower psi.

W/ my ZDYNE, my stock fuel pump only gave me up to 8psi before I leaned out. I have a feeling you have no problem and that all you need is more volume as we've discussed before...

somethimes a mild cam can act as a slight compression increaser...I once had a stock cam and no detonation...swaped it out for an old mild cam I had laying around and started pinging...

somehow, somewhere, you're more efficient...get the new fuel pump already...

 

Walboro 255.
EVIL

 

I'm also gonna recommend the walbro 255lph pump.

 

It's always a good thing when your motor wants more fuel. Get yourself a 255 pump. Your motor is running lean now because of the bigger displacement. you went from 81mm to 84.5mm so offcourse your going to make more power.

 

Thanks for the input guys. I know I need to quit being a dumbass and just buy a bigger fuel setup. Idealy I'd like to run a Walbro 255 and some 65# or 72# injectors. This is a street car and if it's making enough power at 8 PSI to tap out a set of 450cc'rs.......1 bar of boost is prolly plenty for the street or even too much. Talk about a vulgar display of power

I thought I'd be able to at LEAST boost 8 PSI. I mean somebody tell me if I'm wrong but isn't the limits of 450cc injectors like 275whp ? I'm not bragging or anything but damn, that's pretty stout for only 8psi.

As for the DRAG manifold boost creeping i'm aware of that problem, so I ported the DRAG mani out some, matched it to the exhaust and wastegate gaskets. That seemed to help out with the creep problems. It would hold 10psi rock steady all the way to redline.

 

You can NEVER have to much power. HEHEHE!

 

Yeah man, I have 75lb injectors and a wallbro 255 and I have massive amounts of fuel at 1 BAR. The new pump alone couldn't hurt if ya have to do one first.

 

fuel pump!

 

If you were running a 90% duty cycle at 8psi with your old setup you deff. need at least a new pump and raise your fuel pressure but you should just go ahead and get soem larger injectors and make use of that built block.

 

that duty cycle is wayyy tooo much for me to handle. I would definitly drop in some huge injectors and a big pump, you have a Zdyne, you can handle it. Sell those injectors to one of us poor guys that has to the vafc hack....

 

Anybody know where I can get some injectors in the 72#~75# range for relatively cheap? I mean it the holidays and where all strapped for cash around now but I ain't gots no job Pardon the lack of grammer in the previous statement, I was hoping Viren's groupbuy would hold out longer on the Seimens Deka injectors, anybody got/know of a set that can be had for a good price?

 

I got mine from Viren.

 

when was the last time you changed the fuel filter?

 

Changed the fuel filter about 6 months ago. I dunno if Viren is still running his groupbuy on those Siemens Deka, wish I had gotta in on it when I had the chance

 

Plea for someone to hook me up on some big *** injectors.....anybody?