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Hello, I have a 2008 Z06 that has a Mast Motorsports Cam, Brian Tooley Racing P&P Heads, FAST LSXR 102mm intake, FAST fuel rails with ZR1 injectors, LG Long tubes and a 102MM TB. I just got the car, and was looking at the fuel system as it has a tune, but needs a better one so trying to get everything set before I do that.
On the FAST fuel rails, I have the inlet, crossover to the driver side but then the drivers side is capped off with no return that I can see. Ive been around cars and rebuilt enough that they always have a return that I have done, but I asked a tuner friend of mine and he said they doglegged it off and its really capped at 600HP because of the set up. He said I should get a different set up really but didnt have any suggestions. I am new to the Corvette world, but did have a 2018 ZL1 but it was stock so this is new how things are ran on this car. Ive attached some pictures as I am hoping someone can tell me what I do need or if there is something simple I need to do.
TIA for any help! over all setup Drivers side capped off Pass Side AN Fitting coming in with SS braided line
With a boost-a-pump and Racetronix fuel pump harness the stock setup with injectors is good to 700+ rwhp easily. You don't need a return setup until you get well north of that.
I'm at 770 rwhp with stock fuel system except boost-a-pump, injectors and NO Racetronix harness. Yet to be installed.
Have friend pull the injector percentages now on a red line pull, If over 80%, then fuel system now is board line on keeping up with the motor.
The other one you did not mention, is if there is a BAP in play, that is over voltage'g the fuel pump, so it can put out more pressure and volume.
As for no return line in the fuel rail, normal for the Stock C6 fuel system, including if BAP is in play.
As for better tune with what you got, maybe, but only if old tuner ran into fuel pressure/injector percentages problems ,and that capped off just how far they could push the tune for motor to make more power.
Truth is, higher RPMs allows for higher HP numbers, and the problem with the LS7, has always been the intake manifold, with not enough room up the hood to allow the engine to breath cleanly to its stock 7K rrmp instead. In stock form, LS7 starts to go flat around 5.9K with HP not climbing much, you can lean out the afr a little about that point to get the motor climb a little better to about 6.4K, but lost cause after that to 7K, until you can get a intake manifold to allow it to breath cleanly to 7K.
Hence the reason that most will just go with a blower putting out out about 6psi, that allows motor breathes to 7K without problems.
Note, do not try to boost stock LS7 past 6lbs, the cylinder walls between the clylinders are to thin, and with the stock compression of the motor, going to blow the cylinders every time.
LS9 with thicker cylinder walls between Cylinders, and the fact that the compression has been lowered, is the reason that you can use a hell of lot more pressure on that block for super charging instead.
So really, before you go down the rabbit hole of trying to get better tune, Dyno the motor now, with AFR turned on in the dyno graph, and use basic scanner to see what the injector percentage rates are (so you not having to pay the $125 for tuner to use tuning software to start with).
If injector rate is more than 80%, then flirting with fuel flow/pressure rates that may have stopped the old tune from gaining more power ,
and if motor is not gaining power on steady climb rate as before it hit 5.8K, then dealing with intake flow restrictions instead.
Bone stock LS7 with just playing with tune to gain more power within it's intake flow restrictions.
With blower so engine if force feed to breath to 7K without problems, take a ruler to the HP climb rate from 3.5K to 5K above, and draw a line on that curve to 7K to get an idea of what even the stock motor can make when it can breath to 7K cleanly.
With the fast intake, will dare to guess that may have gained a touch more in steady climb rate, but HP steady climb rate still going flat around the 6K mark instead.
As for ported MSD, may get you a little more steady climb over the Fast to slightly higher RPM range, but still not going to get steady climb to 7K, since as stated, just not enough room under the hood to begin with.
Now, lets back this up, and what is the plan for the car.
Hence motor should be in the 650Hp range now, should be able to break the tires on the street without problems, and if your going to use the car for road course work, unless its T1 for increase down force, even the 650HP may be over kill. Hence C6R only made about 650hp, since any more would have just screwed with its handling in the technical sections. Yes more HP may gain you a have second down the straight, but going to cost you at least 10 seconds in the technical section, when you can not control the back end out of the push out of the apex's.
If strip racing, then yes can gain some time at the back end, but still limited to what G you can launch the car out of the hole in the first place, and not have the drive line tears itself apart from a higher G launch.
As for top end speeds, 650hp is more than enough to get you over 200mph, if you have the talent to drive the car that fast.
And if the motor is already tuned to the max is going to make in its form, can still make the motor more savage,by increasing TM values to allow the car to put more instant power to the ground (if TM is still in play), and if you really have the talent for the car to be ungodly/trying to kill you, then throttle remapping to de-soccer mom that is the answer you may be seeking.
Have friend pull the injector percentages now on a red line pull, If over 80%, then fuel system now is board line on keeping up with the motor.
The other one you did not mention, is if there is a BAP in play, that is over voltage'g the fuel pump, so it can put out more pressure and volume.
As for no return line in the fuel rail, normal for the Stock C6 fuel system, including if BAP is in play.
As for better tune with what you got, maybe, but only if old tuner ran into fuel pressure/injector percentages problems ,and that capped off just how far they could push the tune for motor to make more power.
Truth is, higher RPMs allows for higher HP numbers, and the problem with the LS7, has always been the intake manifold, with not enough room up the hood to allow the engine to breath cleanly to its stock 7K rrmp instead. In stock form, LS7 starts to go flat around 5.9K with HP not climbing much, you can lean out the afr a little about that point to get the motor climb a little better to about 6.4K, but lost cause after that to 7K, until you can get a intake manifold to allow it to breath cleanly to 7K.
Hence the reason that most will just go with a blower putting out out about 6psi, that allows motor breathes to 7K without problems.
Note, do not try to boost stock LS7 past 6lbs, the cylinder walls between the clylinders are to thin, and with the stock compression of the motor, going to blow the cylinders every time.
LS9 with thicker cylinder walls between Cylinders, and the fact that the compression has been lowered, is the reason that you can use a hell of lot more pressure on that block for super charging instead.
So really, before you go down the rabbit hole of trying to get better tune, Dyno the motor now, with AFR turned on in the dyno graph, and use basic scanner to see what the injector percentage rates are (so you not having to pay the $125 for tuner to use tuning software to start with).
If injector rate is more than 80%, then flirting with fuel flow/pressure rates that may have stopped the old tune from gaining more power ,
and if motor is not gaining power on steady climb rate as before it hit 5.8K, then dealing with intake flow restrictions instead.
Bone stock LS7 with just playing with tune to gain more power within it's intake flow restrictions.
With blower so engine if force feed to breath to 7K without problems, take a ruler to the HP climb rate from 3.5K to 5K above, and draw a line on that curve to 7K to get an idea of what even the stock motor can make when it can breath to 7K cleanly.
With the fast intake, will dare to guess that may have gained a touch more in steady climb rate, but HP steady climb rate still going flat around the 6K mark instead.
As for ported MSD, may get you a little more steady climb over the Fast to slightly higher RPM range, but still not going to get steady climb to 7K, since as stated, just not enough room under the hood to begin with.
Now, lets back this up, and what is the plan for the car.
Hence motor should be in the 650Hp range now, should be able to break the tires on the street without problems, and if your going to use the car for road course work, unless its T1 for increase down force, even the 650HP may be over kill. Hence C6R only made about 650hp, since any more would have just screwed with its handling in the technical sections. Yes more HP may gain you a have second down the straight, but going to cost you at least 10 seconds in the technical section, when you can not control the back end out of the push out of the apex's.
If strip racing, then yes can gain some time at the back end, but still limited to what G you can launch the car out of the hole in the first place, and not have the drive line tears itself apart from a higher G launch.
As for top end speeds, 650hp is more than enough to get you over 200mph, if you have the talent to drive the car that fast.
And if the motor is already tuned to the max is going to make in its form, can still make the motor more savage,by increasing TM values to allow the car to put more instant power to the ground (if TM is still in play), and if you really have the talent for the car to be ungodly/trying to kill you, then throttle remapping to de-soccer mom that is the answer you may be seeking.
Thanks, my plan is really not to go to much further with the car in terms of performance. Some simple upgrades to suspension/brakes etc would be about it. Currently the drivability at low speeds is trash. It has a twin disk clutch in it and I have stalled this car more times than I can count trying to pull into my driveway or garage. And when I am just starting out, it just bucks until I get some speed behind it. The idle is all over the place so that is what is leading me to thinking the tune is bad and/or fuel is not enough. Like I said, this is my first go around with a vette, but my TT Viper I had 2 years ago that put 1300 down drove better at low speeds than this.
Thanks, Currently the drivability at low speeds is trash. It has a twin disk clutch in it and I have stalled this car more times than I can count trying to pull into my driveway or garage.
Problem is someone installed lightened flywheel that allows the car to stall when using the clutch (If standard flywheel was still in car then don't need to touch gas pedal to get car moving), and will bank that inorganic clutch discs wer installed, not a organic clutch that allows the clutch to be slipped with ease.
So would double check, but if can not get used to to lightened flywheel, then go back to standard weight, and on the clutch, increase tension pressure plate with organic discs.
"And when I am just starting out, it just bucks until I get some speed behind it. The idle is all over the place so that is what is leading me to thinking the tune is bad and/or fuel is not enough. Like I said, this is my first go around with a vette, but my TT Viper I had 2 years ago that put 1300 down drove better at low speeds than this."
Could be tune, or could just be more aggressive cam that has the motor surging low rpm, that your not going to solve until you go milder cam instead.
So looks like your going to spend big bucks on the car you bought, to get it back to something you can use.
Hence clutch and flywheel replacement, and will bank swapping out cam to something less aggressive that does not have low RPM surge in stop and go traffic.
So on that note, hope you got an extra $7K in the bank, since that's about what it going to cost to get the car to drive like you want in the end (with new clutch and standard weight flywheel, new cam and then re-tune). And on the cam swap, make sure they pull the heads, so they can replace the lifter trays with new GM lifter trays, if the lifters are not linked now.
As for a side note, surprised that you bought the car in the first place, since car was not driving like you wanted, and problem is really not in the tune or fuel pressure for the problems you listed in the first place.
Problem is someone installed lightened flywheel that allows the car to stall when using the clutch (If standard flywheel was still in car then don't need to touch gas pedal to get car moving), and will bank that inorganic clutch discs wer installed, not a organic clutch that allows the clutch to be slipped with ease.
So would double check, but if can not get used to to lightened flywheel, then go back to standard weight, and on the clutch, increase tension pressure plate with organic discs.
"And when I am just starting out, it just bucks until I get some speed behind it. The idle is all over the place so that is what is leading me to thinking the tune is bad and/or fuel is not enough. Like I said, this is my first go around with a vette, but my TT Viper I had 2 years ago that put 1300 down drove better at low speeds than this."
Could be tune, or could just be more aggressive cam that has the motor surging low rpm, that your not going to solve until you go milder cam instead.
So looks like your going to spend big bucks on the car you bought, to get it back to something you can use.
Hence clutch and flywheel replacement, and will bank swapping out cam to something less aggressive that does not have low RPM surge in stop and go traffic.
So on that note, hope you got an extra $7K in the bank, since that's about what it going to cost to get the car to drive like you want in the end (with new clutch and standard weight flywheel, new cam and then re-tune). And on the cam swap, make sure they pull the heads, so they can replace the lifter trays with new GM lifter trays, if the lifters are not linked now.
As for a side note, surprised that you bought the car in the first place, since car was not driving like you wanted, and problem is really not in the tune or fuel pressure for the problems you listed in the first place.
I bought the car at auction online actually. Didnt plan on it, but put a bid in and didnt think it would hit reserve. So really got a killer deal. Its a McLeod Racing TXT twin disk clutch and said it has a Mast Motorsports mild cam is what was listed in the auction. Nothing about a lightened flywheel. I am finishing up cleaning somethings up on it and then plan on taking it to my tuner to have him just do a base line and see what he thinks. I also havent put gas in it since the front tires were horrible and waiting on the new rims to be finished so I can get the tires mounted before I can really drive it.
As for mild cam, let your tuner see what he can do to clean up lower RPM surging if possable, But if higher ratio lifters involved, could be part of it as well.
Z06 Fuel Systems
