G35 Build 2nd Try
255? You have a Twin Pump?
Sorry, I don't remember all the details about your car.
Sorry, I don't remember all the details about your car.
Well took the car out today to do a little data logging to see if anything looks off before i try to schedule my tune.
Well i learned a few things:
1: Something may be misaligned. I ate part of my belt, when i popped my hood the belt was hanging off the front of the alternator so need to order a few belts and get some sort of square to check alignments.
2: I may have a bad alternator, car died on me and struggled to start (Brand new battery) I think it's more than likely dude to the power steering leak i have that has coated the alternator in lovely juices.
3: Need to fix my dam power steering leak...
4: Don't take passengers when trying to data log, the right foot may get a little heavy. Pinned it in 3rd for about 3 seconds hit 80 and let out. That did give me some very good data though.
5: Injector duty cycle is hit 70% so i either need a bigger fuel pump my 255 may not be enough, or i could set my fuel pressure regulator to scale with boost instead of the static 53psi i currently have it at.
6: 5880rpm in 3rd = 15psi so if i rev to 7200 in 5th i think that should be close to 18-19psi if i don't have any belt slip.
More to come, and i expect a lot of flack of stretching its legs with no "tune"
Well i learned a few things:
1: Something may be misaligned. I ate part of my belt, when i popped my hood the belt was hanging off the front of the alternator so need to order a few belts and get some sort of square to check alignments.
2: I may have a bad alternator, car died on me and struggled to start (Brand new battery) I think it's more than likely dude to the power steering leak i have that has coated the alternator in lovely juices.
3: Need to fix my dam power steering leak...
4: Don't take passengers when trying to data log, the right foot may get a little heavy. Pinned it in 3rd for about 3 seconds hit 80 and let out. That did give me some very good data though.
5: Injector duty cycle is hit 70% so i either need a bigger fuel pump my 255 may not be enough, or i could set my fuel pressure regulator to scale with boost instead of the static 53psi i currently have it at.
6: 5880rpm in 3rd = 15psi so if i rev to 7200 in 5th i think that should be close to 18-19psi if i don't have any belt slip.
More to come, and i expect a lot of flack of stretching its legs with no "tune"
Pump
Well the relay is wired in and pump is purring like a kitten.
In the process i may have discovered a few things:
1) Wiring in not my forte'! It's functional but doesn't look very good the wires are not the same length so it looks poopy but it's under a seat so no one will see it.
2) I can't get my fuel pressure below 60 psi, i can get it to go up but i can't get it below 60. So either i have bad FPR or using the stock hard line feed line is causing the pressure to spike, doesn't make sense though. At the same setting my 255 pump was reading 52 psi. Then again the 255 was using stock wiring so may not have been running at full power.
Things left to do:
1) TUNE....
2) Rear Wheel/Tire Set up
3) Figure out where to put my catch can
4) Oil Cooler, not a huge priority since blower is self contained and doesn't use engine oil to keep cool and lubricated. Also i don't plan on beating on the car that often....
In the process i may have discovered a few things:
1) Wiring in not my forte'! It's functional but doesn't look very good the wires are not the same length so it looks poopy but it's under a seat so no one will see it.
2) I can't get my fuel pressure below 60 psi, i can get it to go up but i can't get it below 60. So either i have bad FPR or using the stock hard line feed line is causing the pressure to spike, doesn't make sense though. At the same setting my 255 pump was reading 52 psi. Then again the 255 was using stock wiring so may not have been running at full power.
Things left to do:
1) TUNE....
2) Rear Wheel/Tire Set up
3) Figure out where to put my catch can
4) Oil Cooler, not a huge priority since blower is self contained and doesn't use engine oil to keep cool and lubricated. Also i don't plan on beating on the car that often....
New Member
Joined: Aug 2004
Posts: 160
Likes: 45
I'm not sure, sounds like it should be as the CJM stage 1 is that, I'm using the stage 2 and the feed is 8 and the return is the factory line. I'm also on a single 485 pump.
Quick way to test is to replumb the return into a gas can and run the pump for a bit and see. I'm assuming you have the vac line disconnected to set the pressure? If the reg can't go that low after the test and with the vac line off, I'd strongly suspect the reg.
Quick way to test is to replumb the return into a gas can and run the pump for a bit and see. I'm assuming you have the vac line disconnected to set the pressure? If the reg can't go that low after the test and with the vac line off, I'd strongly suspect the reg.
I'm not sure, sounds like it should be as the CJM stage 1 is that, I'm using the stage 2 and the feed is 8 and the return is the factory line. I'm also on a single 485 pump.
Quick way to test is to replumb the return into a gas can and run the pump for a bit and see. I'm assuming you have the vac line disconnected to set the pressure? If the reg can't go that low after the test and with the vac line off, I'd strongly suspect the reg.
Quick way to test is to replumb the return into a gas can and run the pump for a bit and see. I'm assuming you have the vac line disconnected to set the pressure? If the reg can't go that low after the test and with the vac line off, I'd strongly suspect the reg.
A new reg isn't in the budget so it looks like i'll be running at 60 psi. I don't plan on having the fuel pressure adjust with boost unless absolutely necessary.
I don't immediately know the adverse effect of running 60psi versus 52psi but maybe others can chime in...
There's really no adverse effect in running a few more psi of base fuel pressure (assuming you correct your tune), I've only heard that you want to keep total fuel pressure below 90 psi (base plus 1 psi for each pound of boost)
Last edited by thatv35guy; May 7, 2019 at 09:13 AM.
I plan on running a static 60 psi, instead of having it vary with boost. I don't see a benefit of having my fuel pressure change with boost if i have enough fuel at a static pressure. No need in putting unneeded stress on the fuel system.
Yes - keep 60psi as your base but when your supercharger is making positive boost pressure - say up to 16psi (or whatever youre going to run) you have THAT amount of boost pressure pushing against your injectors ... so at peak boost (assume 16psi) you have your fuel pump going at 60psi on one end and your blower creating intake charge at 16psi on the other end ... you're effectively pushing 44psi of fuel pressure. So now you are under-fueling based on pressure.
whats the harm in running the FPR in a traditional manner?
Last edited by bealljk; May 7, 2019 at 07:14 PM.
New Member
Joined: Aug 2004
Posts: 160
Likes: 45
Yup, rising rate is the way to go. You get less psi at vac/low boost so idle is easier, and you get a constant diff as boost rises so you don't run out of injector as fast due to trying to spray into pressure. I know the two TT's we did, the first one was fixed with just a UTEC flash and it always had a small dead spot and high duty cycles. We converted to a CJM S1 and rising rate and it tuned much better (no other changes).
You're placing zero additional stress on the fuel system by running a rising rate fuel pressure regulator, ZERO. I would never, ever run one of these cars without one.
A 485 Pump with a Stock Feed Line........
Do yourself a favor and get a piece of stock fuel feel and look at the Inside Diameter!
Do yourself a favor and get a piece of stock fuel feel and look at the Inside Diameter!
Well the relay is wired in and pump is purring like a kitten.
In the process i may have discovered a few things:
1) Wiring in not my forte'! It's functional but doesn't look very good the wires are not the same length so it looks poopy but it's under a seat so no one will see it.
2) I can't get my fuel pressure below 60 psi, i can get it to go up but i can't get it below 60. So either i have bad FPR or using the stock hard line feed line is causing the pressure to spike, doesn't make sense though. At the same setting my 255 pump was reading 52 psi. Then again the 255 was using stock wiring so may not have been running at full power.
Things left to do:
1) TUNE....
2) Rear Wheel/Tire Set up
3) Figure out where to put my catch can
4) Oil Cooler, not a huge priority since blower is self contained and doesn't use engine oil to keep cool and lubricated. Also i don't plan on beating on the car that often....
In the process i may have discovered a few things:
1) Wiring in not my forte'! It's functional but doesn't look very good the wires are not the same length so it looks poopy but it's under a seat so no one will see it.
2) I can't get my fuel pressure below 60 psi, i can get it to go up but i can't get it below 60. So either i have bad FPR or using the stock hard line feed line is causing the pressure to spike, doesn't make sense though. At the same setting my 255 pump was reading 52 psi. Then again the 255 was using stock wiring so may not have been running at full power.
Things left to do:
1) TUNE....
2) Rear Wheel/Tire Set up
3) Figure out where to put my catch can
4) Oil Cooler, not a huge priority since blower is self contained and doesn't use engine oil to keep cool and lubricated. Also i don't plan on beating on the car that often....
Thanks for all the input fellas, once i get back home ill get the CJM -6 to oem fuel quick disconnect and some -8 steel braided fuel line. I will also hook my fpr up to the manifold so i can get my 1:1 scaling.