[CaliforniaKid]

That is great info thank you!

Originally Posted by travislambert

Don't do it unless you are prepared to make a lot of other changes to the car. The default 90mm pulley is too much boost for the stock fuel pump to keep up on a road course. I told Magnuson about this but I don't know if they ever did anything about it. At a minimum you'll need a JMS voltage booster to keep fuel supplied. Don't even consider the supplemental kits like the one from DSX Tuning. It's junk and completely worthless for road course use on a car with a saddle tank.

The next problem you'll have is heat. With the extra power comes a lot more heat. The stock cooling cannot keep up on a hot track day. My coolant temps are going 240+ and my oil temps are 290+. The transmission temps were a lot hotter too (about 240). I've fixed the trans temps with a supplemental cooler. I have a new primary radiator, center heat exchanger for the supercharger, and a custom oil cooler coming.

I plan to follow up at some point after I get all of the issues sorted.

[radz28]

Originally Posted by CaliforniaKid

Any updates OP? I’m thinking of getting one for my ZLE. I also love to go to the road course and don’t want any knocking/heat issues. From what it seems you can order them now that come with a map meant for 91 octane on a stock car.... 700whp or so? I’ll link the video I saw from Magnuson at the bottom. I wouldn’t mind doing a 50/50 100 octane to 91 octane mix on road course days just to play it safe. Opinions?

https://youtu.be/qeXS1QpzadY

Regarding your information about a 91-octane tune: It looks like, like I do, you live in CA. There is a CARB-intent (they're still working on approval) tune, which means it would be tuned for 91, so in that regard, you are probably covered pretty well. I bet your fuel mix or a good additive like RaceGas or Boostane will be good for higher octane.

Originally Posted by travislambert

Don't do it unless you are prepared to make a lot of other changes to the car...

I don't know if you saw a post I left in another thread about Holley's Hydramat: https://www.summitracing.com/parts/h...xoC-X0QAvD_BwE Do you have any experience or anecdotal information about that?

[travislambert]

Originally Posted by radz28

...
I don't know if you saw a post I left in another thread about Holley's Hydramat: https://www.summitracing.com/parts/h...xoC-X0QAvD_BwE Do you have any experience or anecdotal information about that?

No, I don't, but I don't think the pickup itself is really the problem like it may be on a standard fuel tank.

The problem I experienced was due to the saddle tank design. On the road course, a hard turn will cause the fuel to completely transfer from one side of the tank to the other. With less than 1/2 tank of fuel, it's common for one side of the tank to be effectively dry. When the pump is only pulling fuel from the left side, it's far less efficient than when pulling from both sides or even just the right side. I kept losing fuel pressure on the straights after a hard right turn. In stock form, the car's low side pump barely maintains fuel pressure in this scenario. With the upgraded supercharger, it has no chance. I would bet the problem still exists with the 100 mm upper pulley Magnuson offers.

[radz28]

Originally Posted by travislambert

No, I don't, but I don't think the pickup itself is really the problem like it may be on a standard fuel tank.

The problem I experienced was due to the saddle tank design. On the road course, a hard turn will cause the fuel to completely transfer from one side of the tank to the other. With less than 1/2 tank of fuel, it's common for one side of the tank to be effectively dry. When the pump is only pulling fuel from the left side, it's far less efficient than when pulling from both sides or even just the right side. I kept losing fuel pressure on the straights after a hard right turn. In stock form, the car's low side pump barely maintains fuel pressure in this scenario. With the upgraded supercharger, it has no chance. I would bet the problem still exists with the 100 mm upper pulley Magnuson offers.

Ah. I think I'm not familiar with the way the system functions and transfers nearly as much as you. It's certainly not the first (nor will be the last) time I need to learn... I need to learn how it siphons. But this mat doesn't (apparently) require complete submersion in fuel in order to siphon, so it seems if you were to fashion this mat on both sides of the tank (to whatever the facility it is in the tank to make the fuel transfer) that both sides would be dry before you'd lose fuel pressure - theoretically... I'm probably missing a lot, so my apologies... I'll do some more research.

[travislambert]

Originally Posted by radz28

Ah. I think I'm not familiar with the way the system functions and transfers nearly as much as you. It's certainly not the first (nor will be the last) time I need to learn... I need to learn how it siphons. But this mat doesn't (apparently) require complete submersion in fuel in order to siphon, so it seems if you were to fashion this mat on both sides of the tank (to whatever the facility it is in the tank to make the fuel transfer) that both sides would be dry before you'd lose fuel pressure - theoretically... I'm probably missing a lot, so my apologies... I'll do some more research.

From my understanding, the mat would help if the fuel were near the pickup but just outside of reach. I don't think that's the problem. In the scenario where I noticed the problem, the left side of the tank has lots of fuel and the right side of the tank effectively has no fuel. For the left side, you don't need an upgraded mat because the pickup is already submerged. On the right side, there's effectively no fuel available. I wouldn't think a mat would help much other than whatever fuel is held within the mat might give a touch more buffer. At the rate these cars drink fuel at WOT, my gut feeling is that would almost be negligible benefit. I could be wrong though.

The JMS voltage booster seems to solve the problem at the 700 RWHP mark (93 octane), although I'm not of fan of its somewhat significant 24x7 power consumption. I had planned to hookup a relay with heavy duty diodes to cut power from the JMS booster while maintaining power to the FPCM (to keep the computers happy). I bought all of the stuff to do it, but haven't found the time yet.

[radz28]

Originally Posted by travislambert

From my understanding, the mat would help if the fuel were near the pickup, but just outside of reach. I don't think that's the problem. In the scenario where I noticed the problem, the left side of the tank has lots of fuel and the right side of the tank effectively has no fuel. For the left side, you don't need an upgraded mat because the pickup is already submerged. On the right side, there's effectively no fuel available. I wouldn't think a mat would help much other than whatever fuel is held within the mat might give a touch more buffer. At the rate these cars drink fuel at WOT, my gut feeling is that would almost be negligible benefit. I could be wrong though.

The JMS voltage booster seems to solve the problem at the 700 RWHP mark (93 octane), although I'm not of fan of its somewhat significant 24x7 power consumption. I had planned to hookup a relay with heavy duty diodes to cut power from the JMS booster while maintaining power to the FPCM (to keep the computers happy). I bought all of the stuff to do it, but haven't found the time yet.

Ah. Interesting... Thank you for the information!

[KingLT1]

Originally Posted by travislambert

From my understanding, the mat would help if the fuel were near the pickup but just outside of reach. I don't think that's the problem. In the scenario where I noticed the problem, the left side of the tank has lots of fuel and the right side of the tank effectively has no fuel. For the left side, you don't need an upgraded mat because the pickup is already submerged. On the right side, there's effectively no fuel available. I wouldn't think a mat would help much other than whatever fuel is held within the mat might give a touch more buffer. At the rate these cars drink fuel at WOT, my gut feeling is that would almost be negligible benefit. I could be wrong though.

The JMS voltage booster seems to solve the problem at the 700 RWHP mark (93 octane), although I'm not of fan of its somewhat significant 24x7 power consumption. I had planned to hookup a relay with heavy duty diodes to cut power from the JMS booster while maintaining power to the FPCM (to keep the computers happy). I bought all of the stuff to do it, but haven't found the time yet.

24/7 power consumption? Mine shuts off just like the rest of the controllers a couple minutes after the vehicle is turned off. Or at least I think it does...the green LED turns off on the unit.

[travislambert]

Originally Posted by KingLT1

24/7 power consumption? Mine shuts off just like the rest of the controllers a couple minutes after the vehicle is turned off. Or at least I think it does...the green LED turns off on the unit.

The behavior on the SS could be different from the ZL1 on the power going to the FPCM. I know for sure it's a different location in the fuse panel. On my car this wire has constant power, and my understanding was this is normal. It could behave differently on the SS. I don't know.

I could have wired it to an independent relay to ensure it turns off, but I was thinking the FPCM is designed to have constant power. I was afraid I would get codes set for communication failures if power was cut to the FPCM but the other modules in the car were trying to communicate with it.

I let the vehicle sit with a multimeter to monitor current on the power going to the JMS unit.. After about an hour it was still showing about 20 mA of current. This is roughly double what the current usage for the entire car should be after everything is shut down. Normally, an entire vehicle will have a constant draw of 10 mA or less.

Isn't the reason JMS makes a booster specific to GM is to incorporate a low-power sleep mode so it can remain on at all times for the FPCM to maintain power? Unfortunately, it still uses far more power than it should when sitting idle. All they need to fix it is two heavy-duty diodes (40A), a relay, and signal wire for the ignition which is precisely how I plan to fix mine. It would just be nice if it were integrated instead of external.

[Camaro1973]

Originally Posted by NickeyMatt1LE

We have done several 2650 swaps on ZL1's in the past month with similar supporting mods to you, plus headers, 85mm/stock lower and 90mm/5% lower pulley combinations. We see about 750 rwhp through a 10 speed auto at 16 psi, 6600 rpm on 93. You'll be 14-15 lbs at 6500 rpm, 16 psi if you take it to 6800 with that pulley combination. It should make an easy 700 rwhp on 93. The 2650 makes WAY less heat than the stock blower. Even at 15 psi you'll be 30-40 degrees cooler than the stock blower at 9-10 psi. You will loose some torque below 3000 rpm because of the way it ramps boost in. By 4500 though it will be up at least a 100 lb/ft over stock. I think it makes these cars way easier to drive on track. I can post up some dyno sheets when I get back to the shop on Monday if you're interested.

I know this is an older thread but how are you getting anywhere near 750rwhp without a cam or meth?