slownrusty Posted December 23, 2003 Share Posted December 23, 2003 Hi Gang - you might have seen a post where upgraded my fuel rail, added new braided lines with AN fittings where I could and also added an Aeromotive adj. FPR. I do have the stock fuel pump, which I would now like to upgrade to a high volume external pump. The pump on my car is original and has over 145,000miles on it. Its the classic "cowboy syndrome", you know the one where the old cowboy complains that he is not able to pee over the fence like when he was a kid! LOL! Here is what I was thinking: MSD - which supplies 43gallons per hour at 40psi - Price $90: -or- Vortech T-Rex - which supplies 43gallons per hour at 70psi - Price $190: My question is the MSD pump a better pump as it supplies the same volume as the Vortech but at a lower psi? Also what upgraded EFI pumps are you other modded L28ET guys running (looking for recommendations). Thanks! Yasin Quote Link to comment Share on other sites More sharing options...
240hoke Posted December 23, 2003 Share Posted December 23, 2003 Im using the MSD pump, workin good for me so far. What kind of outlet does the 280zx tank have? -Austin Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted December 23, 2003 Share Posted December 23, 2003 I'm using a Bosch pump for a CIS injection (high pressure). OEM for Porsche turbo. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted December 23, 2003 Share Posted December 23, 2003 I know a few guys on here are also running the Walbro pump, which looks very similiar to the MSD pump, but is slightly more expensive. I'm pretty sure I'll be going with the MSD. Quote Link to comment Share on other sites More sharing options...
Jersey Posted December 23, 2003 Share Posted December 23, 2003 I'm running the Walbro GSL-392 255Lph. Think i paid $105 or $110 at the time. Quote Link to comment Share on other sites More sharing options...
Xander Posted December 23, 2003 Share Posted December 23, 2003 I'm also using the MSD pump. Works great and is the cheapest. It's not on a turbo engine though. I'm running it on a fuel injected 260Z. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted December 23, 2003 Share Posted December 23, 2003 So you guys really think that the stock fuel pump is the main reason that 280zxt motors will run lean on the top end (at least, at higher than stock boost levels)? As most of you know I recently dynoed my car and the A/F went WAY rich (10:1 AFR) until about 4000rpm and then started to steadily lean out, to about 13:1 at 5000rpm. I've seen the exact same thing happen on a few other L28ET's. Or... here's another thought, maybe this is an indication that the airflow meter really DOES run out of measurement capacity above 4000rpm at WOT as some guys here have suggested? I need a new pump either way, stock one is on it's last legs so the answer to that question wont change anything regarding that, but I really really want to know if it will be the solution to the lean issue I experienced at the dyno. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted December 23, 2003 Share Posted December 23, 2003 So you guys really think that the stock fuel pump is the main reason that 280zxt motors will run lean on the top end (at least' date=' at higher than stock boost levels)? As most of you know I recently dynoed my car and the A/F went WAY rich (10:1 AFR) until about 4000rpm and then started to steadily lean out, to about 13:1 at 5000rpm. I've seen the exact same thing happen on a few other L28ET's. Or... here's another thought, maybe this is an indication that the airflow meter really DOES run out of measurement capacity above 4000rpm at WOT as some guys here have suggested? I need a new pump either way, stock one is on it's last legs so the answer to that question wont change anything regarding that, but I really really want to know if it will be the solution to the lean issue I experienced at the dyno.[/quote'] I never ran lean, as I was too conservative in my tuning and boost level. I determined by flow testing the stock pump vs. the Bosch, and the stock pump flows 33% less fuel at 50psi than the Bosch. Or put it another way - the Bosch pump flows 50% more fuel than the stock pump at 50psi. Using the formulas for making power based on fuel flow, the L28ET stock pump is only good for a conservative 230hp. It is the first weak link in the stock FI. Quote Link to comment Share on other sites More sharing options...
fl327 Posted December 23, 2003 Share Posted December 23, 2003 I'm using a Bosch pump for a CIS injection (high pressure). OEM for Porsche turbo. Me too. Great pump. Bolts right in. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted December 23, 2003 Share Posted December 23, 2003 Sleeper - you dont mean 230rwhp right? you're talking HP directly from the engine, figured from the math of knowing exactly how much fuel mixed with exactly how much air it takes to make x amount of hp? That would make perfect sense as my 194 at the wheels should be VERY close to that 230 number you mentioned, and the power just leveled off at that point, as did the fuel curve at like 12.7:1, for about 500rpm, where the HP peaked and then started dropping fast as the mixture got rapidly leaner. Thank you sleeper you just increased my confidence tenfold that the pump will indeed solve the lean problem above that point... the numbers add up perfectly to pin the fuel pump as the cause of the problem at that point. Quote Link to comment Share on other sites More sharing options...
john kosmatka Posted December 23, 2003 Share Posted December 23, 2003 What model and year is the oem porsche pump from. Quote Link to comment Share on other sites More sharing options...
fl327 Posted December 23, 2003 Share Posted December 23, 2003 What model and year is the oem porsche pump from. Mine is from a 944, and its just plain sick. I dont think it matters what year. Ive run 80psi at the rail on this pump , and it didnt stutter under load. I didnt run that much pressure on purpose. When I installed an adjustable FPR, I set it too high because it was set at 0 or like 5psi to start with and I just gave it too many turns. I drove it up the block and back, popped the hood and saw my fp guage going nuts, and dropped pressure down to stock levels. I did give it a quick stab, how else do you test your new fpr? First thing I did with the T setup was ditch the stock pump and hotwire the 944 pump with the 12v relay trick. I agree, first thing that should go is that stock pump. Quote Link to comment Share on other sites More sharing options...
slownrusty Posted December 24, 2003 Author Share Posted December 24, 2003 Jersey - Where did you buy your walbro pump? The cheapest I have seen it online is $140. Please let me know. Thanks! Yasin Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted December 24, 2003 Share Posted December 24, 2003 Isn't that Bosch/Porsche pump super-pricey? Quote Link to comment Share on other sites More sharing options...
Jersey Posted December 24, 2003 Share Posted December 24, 2003 Yasin - I think i picked it up from importpoweronline about a year ago. They were having some sort of sale at the time i believe. It looks like they raised the price a bit to $120 now. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted December 24, 2003 Share Posted December 24, 2003 Isn't that Bosch/Porsche pump super-pricey? I've bought many at scrapyards for $15 each. Those pumps are everywhere. It's the new ones that cost money. I bought a new one for $170, but that's rare. Quote Link to comment Share on other sites More sharing options...
slownrusty Posted December 24, 2003 Author Share Posted December 24, 2003 Jersey - Thanks for the reply I will checkout that website for the Walbro. I called Dynamic Motor Sport (who I have dealt with in the past and have provided great service) and they also recommended the Walbro GST392 inline and he said that he would have a price to me by Monday. Just thought I would share. I also noticed this Holley one, looks identical in spec to the Walbro: Specs: Throttle body injection Multi-point injection Forced induction 80 GPH flow @ 15 PSI (at 13.5 volts) 480 PPH flow @ 15 PSI (at 13.5 volts) 5 Amp current draw @ 15 PSI 67 GPH flow @ 45 PSI (at 13.5 volts) 402 PPH flow @ 45 PSI (at 13.5 volts) 8 Amp current draw @ 45 PSI Approx. 800 HP max. - throttle body injection Approx. 700 HP max. - multi-point naturally aspirated Approx. 600 HP max. - multi-point forced induction <---NOTE!!!!! Any thoughts? Price $160 at Summit Regards - Yasin Quote Link to comment Share on other sites More sharing options...
fl327 Posted December 24, 2003 Share Posted December 24, 2003 I like the oem stuff, how many 200k zxt cars are out there on their oem fuel pump? I bet the porsche pump costs a lot retail, since a brake booster is close to 1k.. Got mine from my people at Autobahn, a shop that deals mostly in European cars, and they had one in a bosch box in their spare parts bin, a 944 and the other for a 450sel, 100.00 for two new!!!! I may run one inline someday. 450 sel looks same but has different fittings Quote Link to comment Share on other sites More sharing options...
Roggaman Posted December 24, 2003 Share Posted December 24, 2003 My question is the MSD pump a better pump as it supplies the same volume as the Vortech but at a lower psi? It´s the other way around! If two pumps puts out the same volume, the one that can deliver the highest pressure in doing this, is most likely to be the better one. Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted December 26, 2003 Share Posted December 26, 2003 Peirburg from Cartech, 200lph, doesn't matter what psi, it works. I have seen it peg my FPG at 100psi. Its quiet, comes encased in rubber, and mounts in the factory bracket. Did I mention it is very quiet, you cannot hear it. I think it cost 200 bucks, but 6 years and going strong. Quote Link to comment Share on other sites More sharing options...
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