50psi base fuel pressure

[milkandoj]

Im tuning using evo 8 560's, base pressure set to 43psi (their stock pressure in an evo 8. A manual vr4 is 37 psi).
Got the boost set to 18psi and my duty cycles are peaking 90-94%, i cut the rev limit from 7750 to 7500 to keep them down to.

I know im due for larger injectors, but until i make a decision, is there any reason not to up the base pressure from 43 to 50psi. This will give me 8% more fuel in theory.

Fuel pump is an in tank walbro and have a sard fpr.

Im thinking more of the extra stress on the pump.

I know upping pressure will decrease the pumps max flow, but i wont be anywhere near it with these tiny injectors.

 

[turbovr4]

When my nephew had my eterna before me he did the 50osi but on the 450cc injectors,car was abit boggy taking off but good midgear and top end.big clouds of black smoke(fuel) on boost.but worst of all was 280km to 50lt of fuel around town driving with only occaisional boost. he drove it like this for a couple of months no probs till i changed it back,pump still good 1year later.it was also was jerky between gear changes,i think flooding.

 

[milkandoj]

When my nephew had my eterna before me he did the 50osi but on the 450cc injectors,car was abit boggy taking off but good midgear and top end.big clouds of black smoke(fuel) on boost.but worst of all was 280km to 50lt of fuel around town driving with only occaisional boost. he drove it like this for a couple of months no probs till i changed it back,pump still good 1year later.it was also was jerky between gear changes,i think flooding.

Well of course, all those things you describe are because it wasn't tuned for and just turned up, stock maps are rich enough as i it is.

I will change my global fuel compensation and can adjust dead times if needed.
So any ill effects of drive ability or weird rich spots are not a concern.

Im only looking at the extra strain on the fuel system such as the pump.

 

[JSTYLE]

50psi base pressure will b fine. Run a good 1:1 rising rate regulator and you should beable to make more power.. however be warned this is a "Band aid" technique.

Jon

 

[ozyvr4]

When you turned it up to 43psi, how did it run?

What afr @ wot are you aiming for?

I just fittied some PTE 880cc , but have not done a full wot pull as at the moment waiting until new turbo is in. I was running 85-90% with the 660cc @ 39-40lbs/min but still at 37.5psi fuel pressure.

@ 50psi base you would be getting massive fuel pressure @ full noise. Just make sure all your seals are you to scratch & I would not do if the pump if not rewired.

How are you fusing the pump as I blew a 15a fuse a little while ago with the 255 pump. I read they can draw upto 18amp when flat out. I ended up fitting a resetable 20a circuit breaker that fits into a blade fuse holder. I'll get a pic of it for you.

I paid $5 for the fuse from 1 of my distributors.

 

[milkandoj]

When you turned it up to 43psi, how did it run?

What afr @ wot are you aiming for?

I just fittied some PTE 880cc , but have not done a full wot pull as at the moment waiting until new turbo is in. I was running 85-90% with the 660cc @ 39-40lbs/min but still at 37.5psi fuel pressure.

@ 50psi base you would be getting massive fuel pressure @ full noise. Just make sure all your seals are you to scratch & I would not do if the pump if not rewired.

How are you fusing the pump as I blew a 15a fuse a little while ago with the 255 pump. I read they can draw upto 18amp when flat out. I ended up fitting a resetable 20a circuit breaker that fits into a blade fuse holder. I'll get a pic of it for you.

I paid $5 for the fuse from 1 of my distributors.

I'm running the 560's at 43psi always as that's their standard pressure in an evo8, so i stuck with that. (Or 42.6psi it be exact) They are running well.
If i step from 43psi to 50 that should make them act 8% larger.
I'm peaking at 38lb of flow, 18psi, 11:1 afr. Timing at 14-15 advance on boost. I can get it up to 17 degrees but get i areas of slight knock, so keep it around 15 so be nice to it.
I haven't re wired the fuel pump, i haven't seen the afr walking away on boost, but i should get onto it regardless, cheap insurance.
I can see how you got bored with your 18g lol. It pulls nicely but its getting addictive.

 

[ozyvr4]

Yeah its addictive.

Are you running sd yet?

The boost control solinoids are available now. I'm looking at getting 1 next week.

 

[milkandoj]

Yeah its addictive.

Are you running sd yet?

The boost control solinoids are available now. I'm looking at getting 1 next week.

You were getting pretty good fuel economy with SD yeah? What are you running at idle and cruise, are you cycling around 14.7 with the narrow band (or narrow band sim) controlling it or you run leaner?. I was reading some guys just lock it in open loop and run leaner.

My fuel economy has gone to the shit now i turned the boost up lol more power equals more fuel and i cant keep my foot of the floor, that the main issue.

Im keen to try the boost control also, want more mid range torque, i could dial in more boost in the mid range.

I need to start researching injectors, want something what the dead times are well known so are easy to dial in, and have a good spray pattern.

 

[ozyvr4]

My fuel economy is still quite good. I get 400-450 around town. I am simulating nb from the lc1. It does cycle around 14,7. My combinded ft is pretty good. Have to adajust a little since i only put the injectors in last week end.

I bought the PTE880cc that are sujested to flow 840cc. There is dedicated global & deadtimes for them.

 

[brisvr4]

I've ordered the boost solenoid from Tom guys. Should arrive soon. I'll post up how it goes

 

[ozyvr4]

Good work tim. I will order min next week.

Thanks agan for the diff housing mate. Will start transferring the guts over next week. I am fitting the turbo in 2 weeks. Will be doing at a mates workshop so we can do the exhaust at the same time.

 

[youda]

bringing back this topic. im running 560cc inj with 50psi fuel preassure and walbro 255 what sort of power were you getting? im running ecmlink with a gm airflow meter and a tdo5 20g at 15psi evo 8 cooler and i still seem to be hitting around 92percent duty cycle. afrs under full boost are 11.4. i thought i should be able to run more boost before i hit that 92 percent duty cycle. am i running too rich or is there something wrong here.

 

[milkandoj]

bringing back this topic. im running 560cc inj with 50psi fuel preassure and walbro 255 what sort of power were you getting? im running ecmlink with a gm airflow meter and a tdo5 20g at 15psi evo 8 cooler and i still seem to be hitting around 92percent duty cycle. afrs under full boost are 11.4. i thought i should be able to run more boost before i hit that 92 percent duty cycle. am i running too rich or is there something wrong here.

That's a bit different to what i saw on my car.....

On my car running 50psi base pressure, 10.8 - 11:1 afr and on 21psi, i was hitting 89% Flowing 40lb/min of air. You are running leaner, same fuel pressure yet higher injector duty cycles on much lower boost and therefore lower airflow. Fair difference. (are these afr's you quote from a wideband or your afr targets in your maps? silly question but just checking)


Whats you peak airflow? Email me a log and ill compare it to mine. We have a very similar setup minus my cams. Ill pm you my email address.

If you had the 560's tuned for 43psi pressure you need to adjust it in the ecmlink to go to 50psi base pressure, off my head it goes up ~8% the equations to work it out are on the ecmlink knowledge base and forums.

If your running a gm afm, not a 055 or 609 the airflow numbers aren't really comparable to what im showing coz im still on a mitsi maf. Apparently gm maf's even when dialed in right you show higher peak airflow numbers in you logs, but its still a good ballpark comparison.

Ive just gone sard 800's. I got mine for like $425 cant argue with that.


Things worth checking...... Boost leak test.
Is the fuel pressure dropping? Due to the fuel filter needing changing (cheap and easy job) have you "rewired" the Walbro, i haven't but will in the future. What fuel pressure reg are you using, a good one or some no name ebay job?