TimZ Posted December 16, 2007 Share Posted December 16, 2007 I have Rochester 650cc low imp injectors from FiveO. 2 bar fuel pressure ...no idle problems. 2bar - as in 29psi? Quote Link to comment Share on other sites More sharing options...
JustinOlson Posted December 17, 2007 Share Posted December 17, 2007 This is also a really nice way to add methanol injection IMO: http://www.rossmachineracing.com/dualinjassm.html Regards, Justin Quote Link to comment Share on other sites More sharing options...
datman Posted December 17, 2007 Share Posted December 17, 2007 Yes 2 bar with vacuum. Obviously it runs higher pressure when the engine is running boost Quote Link to comment Share on other sites More sharing options...
datman Posted December 17, 2007 Share Posted December 17, 2007 Quote Link to comment Share on other sites More sharing options...
TimZ Posted December 17, 2007 Share Posted December 17, 2007 Yes 2 bar with vacuum. Obviously it runs higher pressure when the engine is running boost Base fuel pressure usually refers to the fuel pressure that you read when there is zero vacuum. The fuel pressure with vacuum varies, since not everybody has the same idle vacuum. Because of this, it's not a good value to use for comparison purposes. You guys do realize that injector flow ratings are given for 3 bar fuel pressure, right? If you are running with a base pressure of 2.5bar, then the injector flow is derated by ~9%. Quote Link to comment Share on other sites More sharing options...
big-phil Posted December 17, 2007 Author Share Posted December 17, 2007 Thanks guys, yes staged injection is what I meant. If I can run ("only" Clifton you crack me up) 30psi with 550's and meth than I might just get some 620's or 650's so my idle will be ok. I've heard of the trick with the timing and lowering the fuel pressure. Quote Link to comment Share on other sites More sharing options...
datman Posted December 17, 2007 Share Posted December 17, 2007 Yes I realize the rate drops with pressure, WOT in 3rd I hit 52% duty cycle so there is plenty of room for more when I finanlly get around to raising the boost. I should have checked the base pressure like you said, I just wanted to point out that the injectors seem to give a good spray pattern even with low fuel pressure. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted December 17, 2007 Share Posted December 17, 2007 I run 850cc low impedance injectors on my 2.0 4g63. I don't have problems with idle, but I do have some problems tuning very light cruising, where not much fuel is required. My AFRs tend to bounce around from 11 to 16 in that range and I can't do much to make them steady. The car runs great even though the wideband readout shows that the big injector doesn't allow fine adjustment. In all other aspects they work as any other injector would(idle, wot, partial throttle, etc). I did the suggested trick of smoothing the VE table around idle. I have driven the car nearly 30K miles with the large injectors and never regretted putting them in. Shortly I will be running 1600cc injectors on the 5.3 V8. Hopefully it will idle, but it is more drag built so I don't care to much. Quote Link to comment Share on other sites More sharing options...
big-phil Posted December 17, 2007 Author Share Posted December 17, 2007 wow 850's I think I might try a 700ish injector. That should get me well into the 30+ psi range If I ever wanted to? (muha ha ha ha) Quote Link to comment Share on other sites More sharing options...
Thumper Posted December 17, 2007 Share Posted December 17, 2007 wow 850's I think I might try a 700ish injector. That should get me well into the 30+ psi range If I ever wanted to? (muha ha ha ha) That would be interesting to see the limit of the holset turbo on a l28. Just disconnect the wastegate line and let us know.:flamedevi:flamedevi What lasts longer engine or tranny? Quote Link to comment Share on other sites More sharing options...
TimZ Posted December 17, 2007 Share Posted December 17, 2007 I should have checked the base pressure like you said, I just wanted to point out that the injectors seem to give a good spray pattern even with low fuel pressure. The injectors should always be seeing the base pressure - the regulator's job is to make sure of this by moving the rail pressure around to keep the pressure difference across the injector constant. So, even though you had 29psi in the rail, the injectors were still seeing 36psi since they were spraying into a vacuum (of -7psi in this case). This is why it's best to only talk about the base pressure - everything else just confuses things. Quote Link to comment Share on other sites More sharing options...
big-phil Posted December 22, 2007 Author Share Posted December 22, 2007 what about these? 800cc, http://cgi.ebay.com/ebaymotors/Toyota-Supra-87-92-800cc-Direct-Fit-fuel-Injectors_W0QQcmdZViewItemQQcategoryZ33554QQihZ002QQitemZ120200681317QQrdZ1QQsspagenameZWDVW am I pressing my luck that these might be to big? Or these, 680cc http://cgi.ebay.com/ebaymotors/Toyota-Supra-87-92-680cc-Direct-Fit-fuel-Injectors_W0QQcmdZViewItemQQcategoryZ33554QQihZ002QQitemZ120200681322QQrdZ1QQsspagenameZWDVW Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.