Turbo Guru required ASAP.
#16
I'm thinking its not a starvation issue per se, but rather the pump isn't able to meet the duty-cycle you're asking from it, ie 600hp + 30C(?) ambient + hot engine bay temps, etc ... the fuel and pump are getting too hot to keep up, might be why the 997 went to dual in-tank pumps(which is my plan when I replace my pump).
Definitely worth a log under these conditions too.
Cheers,
Definitely worth a log under these conditions too.
Cheers,
#17
I'm thinking its not a starvation issue per se, but rather the pump isn't able to meet the duty-cycle you're asking from it, ie 600hp + 30C(?) ambient + hot engine bay temps, etc ... the fuel and pump are getting too hot to keep up, might be why the 997 went to dual in-tank pumps(which is my plan when I replace my pump).
Definitely worth a log under these conditions too.
Cheers,
Definitely worth a log under these conditions too.
Cheers,
Regarding the dual 997Tt pump set up, I spoke to Kevin about it and my understanding is that it's not really an option without rather extensive machining and modifications to make it work. I assume if it was doable, you'd already see it being done or some vendor would have put a kit together already. Kevin did mention running the battery directly to the fuel pump to minimize losses so that the pump would be getting the most juice. Or something along those lines... I've never been good when it comes to wiring, I drive an ice cream truck for a living...
#18
well let's say at least mid 500's hp, crank, or ~500whp.
The injectors don't help with the pump duty cycle, injector duty cycle yes but not the fuel pump itself.
I agree, different issue from the 3/4 throttle issue, I think.
Definitely some strange going on, but a log will be a great starting point.
Seems to be some guys on 6S.O. with the 997 upgrade, but am continually researching it...definitely possible with some small tweaks.
Would be a sweet upgrade to do the 90L 997 tank with pump...
Trying a big direct power line to the pump w. HD relay would be worth a shot, can only help
The injectors don't help with the pump duty cycle, injector duty cycle yes but not the fuel pump itself.
I agree, different issue from the 3/4 throttle issue, I think.
Definitely some strange going on, but a log will be a great starting point.
Seems to be some guys on 6S.O. with the 997 upgrade, but am continually researching it...definitely possible with some small tweaks.
Would be a sweet upgrade to do the 90L 997 tank with pump...
Trying a big direct power line to the pump w. HD relay would be worth a shot, can only help
I don't think I'm anywhere near 600hp and with the larger injectors wouldn't think duty cycle would be an issue. However, if the pump is marginal, maybe that is the case when combined with high lateral G's. I still don't see how that would correlate to the 3/4 and full throttle issue I mentioned earlier. I just ran yesterday at the track when it was very cool with ambient temps around 10C and it was doing it just the same as on a 30C day. Something strange is afoot... lol.
Regarding the dual 997Tt pump set up, I spoke to Kevin about it and my understanding is that it's not really an option without rather extensive machining and modifications to make it work. I assume if it was doable, you'd already see it being done or some vender would have put a kit together already. Kevin did mention running the battery directly to the fuel pump to minimize losses so that the pump would be getting the most juice. Or something along those lines... I've never been good when it comes to wiring, I drive an ice cream truck for a living...
Regarding the dual 997Tt pump set up, I spoke to Kevin about it and my understanding is that it's not really an option without rather extensive machining and modifications to make it work. I assume if it was doable, you'd already see it being done or some vender would have put a kit together already. Kevin did mention running the battery directly to the fuel pump to minimize losses so that the pump would be getting the most juice. Or something along those lines... I've never been good when it comes to wiring, I drive an ice cream truck for a living...
#19
well let's say at least mid 500's hp, crank, or ~500whp.
The injectors don't help with the pump duty cycle, injector duty cycle yes but not the fuel pump itself.
I agree, different issue from the 3/4 throttle issue, I think.
Definitely some strange going on, but a log will be a great starting point.
Seems to be some guys on 6S.O. with the 997 upgrade, but am continually researching it...definitely possible with some small tweaks.
Would be a sweet upgrade to do the 90L 997 tank with pump...
Trying a big direct power line to the pump w. HD relay would be worth a shot, can only help
The injectors don't help with the pump duty cycle, injector duty cycle yes but not the fuel pump itself.
I agree, different issue from the 3/4 throttle issue, I think.
Definitely some strange going on, but a log will be a great starting point.
Seems to be some guys on 6S.O. with the 997 upgrade, but am continually researching it...definitely possible with some small tweaks.
Would be a sweet upgrade to do the 90L 997 tank with pump...
Trying a big direct power line to the pump w. HD relay would be worth a shot, can only help
#20
Definitely not a street test, would have to be a track test, maybe Velcro the laptop down or have a co-driver cycle it when on a open lapping day, need to replicate the scenario.
Don't know of any factory-like plug-n-play upgrades, short of the 997 idea.
Don't know of any factory-like plug-n-play upgrades, short of the 997 idea.
The only thing I see us that the fuel pump might be a bit marginal and not supply enough fuel when subjected to lateral Gs. This is impossible to log on the street because there are no places to pull 1+G turns on the street. It's also hard to do on the track because you can't lug a laptop with you. Does anyone make a larger capacity fuel pump that would be a direct replacement for the stock one?
#21
I agree with the fuel theory. Are you running the stock FPR? I use the 5bar FPR with Kevin's setup. Others go different routes to increase the fuel flow (rails, two pumps, etc.). It seems like 1.3 is high for your set-up?, but what the heck do I know...LOL
#22
I don't think 1.3bar is too high. It's actually the same as I had with my RUF turbos and RUF ECU. At least on the in dash gauge it indicated 1.3 on both set ups.
#23
#24
^ sounds like you're on the right track. in my limited experience assuming all else ( tune ) is ok and no obvious leaks? it's always a combo of the check valves/n75 or waste gates being unequally adjusted. all that stuff has to be "just" right or boost issues are intermittent and frustrating as hell since the car runs otherwise fine. once you do a pressure test i would replace ALL the check valves incl the n75. reset the actuators to suggested levels and hope for the best. doing all that has cured ALL my boost issues and i struggled with them for a year plus. i'm now at 1.2 solid always when wot with spikes to 1.3. and throttle position or rpm doesn't matter when hammering down.
#26
I'm thinking its not a starvation issue per se, but rather the pump isn't able to meet the duty-cycle you're asking from it, ie 600hp + 30C(?) ambient + hot engine bay temps, etc ... the fuel and pump are getting too hot to keep up, might be why the 997 went to dual in-tank pumps(which is my plan when I replace my pump).
Definitely worth a log under these conditions too.
Cheers,
Definitely worth a log under these conditions too.
Cheers,
#28
there's two. one above the plenum, and the other below that ( forgive me ) looks like a very small round piece of fishing tackle! ( serious )
they are SO cheap that replacing them ALL at once as a preventative is very wise. the one that i discovered being cracked was the one just above the plenum.
the minute i hooked the pressure tester to the turbo to pressure test, it whistled dixie and it was indeed cracked ( they're plastic ) once i replaced all # ( incl the n75!! ) and went back to stock adjustment on my 1.0 bar waste gates my car ran better than since i first took possession of it.
leaks are that hidden and serious to the overall smooth running and optimal performance of the car. i find. the valves are cheap as hell. change them! and good luck man. its frustrating, don't i ( we all! ).. know
they are SO cheap that replacing them ALL at once as a preventative is very wise. the one that i discovered being cracked was the one just above the plenum.
the minute i hooked the pressure tester to the turbo to pressure test, it whistled dixie and it was indeed cracked ( they're plastic ) once i replaced all # ( incl the n75!! ) and went back to stock adjustment on my 1.0 bar waste gates my car ran better than since i first took possession of it.
leaks are that hidden and serious to the overall smooth running and optimal performance of the car. i find. the valves are cheap as hell. change them! and good luck man. its frustrating, don't i ( we all! ).. know
#29
Rennlist Member
OP and pwderhound
datalog your cars, upload it to datazap.me and post here.... some tunes seem to have a boost to max to around 6000 rpms then boost drops off and then there is an overspike
I have seen it on my old GIAC tune, my old Eurodyne tune, my mate's Proto tune... my problem was solved by Tim who tunes my car and with a MAFLESS set up seems to disappear for everyone I talk to
but datalog it and lets look at things like IDC% etc
datalog your cars, upload it to datazap.me and post here.... some tunes seem to have a boost to max to around 6000 rpms then boost drops off and then there is an overspike
I have seen it on my old GIAC tune, my old Eurodyne tune, my mate's Proto tune... my problem was solved by Tim who tunes my car and with a MAFLESS set up seems to disappear for everyone I talk to
but datalog it and lets look at things like IDC% etc