Nathaust Posted August 23, 2006 Share Posted August 23, 2006 Hi, I just finished my intercooler installation and am wondering if 12psi is too high for my l28et. Its running 10psi now and has been sinse I got it and it runs fine. It is pretty much stock except for 3in dp and exhaust. My fuel side is stock injectors/pump as is my ECU/EFI. I went to a 60mmTB and am using a TurboXS BOV. I plan on upgrading my fuel side next while I save for a programable EFI. I'm using a MBC. Can I raise my boost to 12 before upgrading the fuel side? thx jon Quote Link to comment Share on other sites More sharing options...
jtmny1999 Posted August 23, 2006 Share Posted August 23, 2006 I had been boosting 12 to 14 psi on stock FI for a few months and without an intercooler so you should be ok on 12 psi. Quote Link to comment Share on other sites More sharing options...
big-phil Posted August 23, 2006 Share Posted August 23, 2006 I run 15 psi but I have ford 370cc injectors. The stock ones are 270cc so Id be careful. And to tell you the truth I don't go to 15 hardly at all, just when I'm doing one of my stupid videos. Quote Link to comment Share on other sites More sharing options...
veritech-z Posted August 23, 2006 Share Posted August 23, 2006 I wouldn't say those videos are stupid...let's get a 15psi burnout video! Quote Link to comment Share on other sites More sharing options...
Nathaust Posted August 23, 2006 Author Share Posted August 23, 2006 Thanks JTMNY and Phil So with the stock injectors pump and FPR your guys think 12psi is fine? Quote Link to comment Share on other sites More sharing options...
Clifton Posted August 24, 2006 Share Posted August 24, 2006 The stock FPR is good to whatever psi you want. I wouldn't run more than 12-14psi without atleast a wideband. Quote Link to comment Share on other sites More sharing options...
slownrusty Posted August 24, 2006 Share Posted August 24, 2006 At 12psi you're pushing it. This was my old set-up... 10psi with an Isuzu NPR IC, HKS SSQ BOV 60mm TB 3" exhaust stock down pipe stock EFI stock electronics stock T3 turbo car ran like a bullet...and pretty much took down some pretty big game with it. So be careful that extra 2psi.....you never know without an EGT or wideband. Yasin Quote Link to comment Share on other sites More sharing options...
dapiper Posted August 24, 2006 Share Posted August 24, 2006 We just flowed some "STOCK" turbo inj at 260cc/min at 38 psi (30PPH), good for 280 hp at 0.6 BSFC and 90% duty. Should be OK at 12 psi with I/C as long as pump can keep up, not sure about additional back press from boost restricting pump. I know stock non-turbo pump cannot handle any backpress and only flowed 25 GPH. Some "replacement" inj only flowed 235cc/min with bad spray pattern. Quote Link to comment Share on other sites More sharing options...
big-phil Posted August 24, 2006 Share Posted August 24, 2006 I wouldn't say those videos are stupid...let's get a 15psi burnout video! Oooo those tires cost a little to much, here is another motorcycle clip of me roasting the tire at a burn out competion. I get the bike tires for free. I like the new sig. pic.! Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted August 25, 2006 Share Posted August 25, 2006 erm... why would you ever boost over 10psi without an intercooler!! you guys worry me.. wait till you blow ur first engine Quote Link to comment Share on other sites More sharing options...
slownrusty Posted August 25, 2006 Share Posted August 25, 2006 I had been boosting 12 to 14 psi on stock FI for a few months and without an intercooler so you should be ok on 12 psi. Kabooom! Quote Link to comment Share on other sites More sharing options...
Nathaust Posted August 25, 2006 Author Share Posted August 25, 2006 Ok guys your scaring me now. So you think 12psi might be pushing it? I was running fine at 10 without my intercooler and now that I have it I should be wary to up the boost with the stock fuel side? I don't have a EGT or proper wideband yet but I'm going to run a Air-fuel meter from 3 bar racing http://www.3barracing.com/product_3.htm for some insight into if I'm running lean or not. I know that these voltage based air/fuel meters are a far cry from a real wideband but I thought it would be better then nothing untill I can afford a real one. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted August 25, 2006 Share Posted August 25, 2006 take your time... be patient... dont rush into boost.. unless you enjoy changing engines out every week... i would highly advise going wideband with the stock efi.. youve been fine with 10psi and below.. why do you need more this very minute untill you can afford wideband? buy a Innovate Wideband with guage for $200... and ur done Quote Link to comment Share on other sites More sharing options...
Pyro Posted August 25, 2006 Share Posted August 25, 2006 I run 14 psi with the stock NA injectors and ecu. However, I have a fmu that jacks the fuel pressure up to 95 psi at that boost level plus a fuel pump system from hell. All you need is a little more fuel pressure. 45 or 50 psi during boost should do it. The higher the boost, the less the injectors will flow. When the manifold is under positive pressure it slows the fuel volume from the injectors due to less pressure difference (boost pressure- fuel pressure). If the boost pressure was the same as the fuel pressure, no flow would come out of the injectors. Maybe all you need is a pressure sensitive fpr. Quote Link to comment Share on other sites More sharing options...
veritech-z Posted August 25, 2006 Share Posted August 25, 2006 So is the concensus that the n/a fuel pump is not sufficient for any boost at all? I was only looking for 6-7 psi for now... Nice video Phil! I was a little sad when I saw you scraping on the 12 o'clock bars (always seemed like cheating to me) until I saw the no-handed wheelie with no scrape! Rock! I'll try and get a burnout vid once I finish this dang megasquirt installation... Quote Link to comment Share on other sites More sharing options...
Pyro Posted August 25, 2006 Share Posted August 25, 2006 I used a NA efi pump on retro-fit turbo and it worked ok with stock boost. I only upgraded my fuel system when I turned up the boost. Quote Link to comment Share on other sites More sharing options...
big-phil Posted August 25, 2006 Share Posted August 25, 2006 I,ve got 2 fuel pumps. The stock n/a one and a holly. The guy who put my tranny in my Z said the n/a and turbo fuel pump are the same? Quote Link to comment Share on other sites More sharing options...
Clifton Posted August 25, 2006 Share Posted August 25, 2006 10 psi without an intercooler isn't risky if there is no knock. It is no more risky than running 18 psi with an intercooler and no knock. I run 12 psi for the 8 cooler months out of the year on my Z31 with no intercooler, have been doing it for 2 years. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted August 25, 2006 Share Posted August 25, 2006 I have run 20psi with the stock 1978 280z n/a fuel pump.. no leaning out issues Quote Link to comment Share on other sites More sharing options...
TimZ Posted August 26, 2006 Share Posted August 26, 2006 I,ve got 2 fuel pumps. The stock n/a one and a holly. The guy who put my tranny in my Z said the n/a and turbo fuel pump are the same? I'm pretty sure they are not the same. As I recall the n/a pump has a pressure relief valve that limits its output pressure to ~50-55psi. The turbo pump has a higher pressure relief point - ~65psi as I recall. 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.