[regnouy37]

Originally Posted by BMWM.D.

I’m guessing here, but I bet the ZR1 has much better manifolds + 3” exhaust. While long tubes are great for their scavenging ability, a lot of the recommendation has to do with flow. You don’t necessarily need long tube headers, but you need something that flows better than the LT1 manifolds that come on our cars. I don’t think you have any real options, though.

My personal opinion is that you probably don’t want to do any pulley changes without headers. I also don’t think you’ll get the gains Ted got from tuning without race fuel. His gains also looked more impressive because he was getting big time throttle closure on his baseline. They don’t always do that. I’m guessing the cold weather where he is made it more of a factor.

I’ve heard mixed results on the heat exchanger upgrades. I’ve built a number of Magnuson blown (TVS2300 and MP122) setups for me and my friends over the years, and I’ve always found the coolant hoses going to/from the blower to be lukewarm at most. This is with a single, modest sized heat exchanger. Maybe it’ll help more on a road course, but I’ve also heard guys claim that you just end up with more warm water in the system.

Food for thought: my A10 car did a 10.79 @ 132.7 mph in mediocre weather with really just an intake, headers, and ported TB. I also did minor tuning myself. Something like that should be as reliable as stock, with no worries about extra heat or a need for additional octane.

Those are solid numbers for an intake, headers, ported TB, and tune. Do you daily drive your car, and what are your future plans in terms of modifications?

[BMWM.D.]

Originally Posted by regnouy37

Those are solid numbers for an intake, headers, ported TB, and tune. Do you daily drive your car, and what are your future plans in terms of modifications?

Thanks. I was pleasantly surprised by the trap speeds given +1300 DA. It’s a weekend hotrod for me. I certainly could daily it, but I’m like a mile from work and I’d rather it not sit on the street all day.

I have done a 2.30” upper pulley since then. That’s all I think I’m gonna do. The thing spins the stock tires at 75 mph, and I’m pretty sure it’ll be a 10.5 / 135 mph car as it sits. Maybe I’ll dabble in flex fuel tuning, as our 91 octane out here kind of sucks. I also have been meaning to send the TCM out to get it unlocked, so I can raise torque limits and whatever else. That 10.79 was with the stock trans tune.

[regnouy37]

Originally Posted by BMWM.D.

Thanks. I was pleasantly surprised by the trap speeds given +1300 DA. It’s a weekend hotrod for me. I certainly could daily it, but I’m like a mile from work and I’d rather it not sit on the street all day.

I have done a 2.30” upper pulley since then. That’s all I think I’m gonna do. The thing spins the stock tires at 75 mph, and I’m pretty sure it’ll be a 10.5 / 135 mph car as it sits. Maybe I’ll dabble in flex fuel tuning, as our 91 octane out here kind of sucks. I also have been meaning to send the TCM out to get it unlocked, so I can raise torque limits and whatever else. That 10.79 was with the stock trans tune.

That’s nuts and a true testament that the highest horsepower #’s don’t always equal the best #s. I’m a firm believer in functionality and efficiency!

How has your cooling been since you added the upper pulley? I’d like to see how your numbers look on Ethanol.

[GunMetalGrey]

Originally Posted by BMWM.D.

I’m guessing here, but I bet the ZR1 has much better manifolds + 3” exhaust. While long tubes are great for their scavenging ability, a lot of the recommendation has to do with flow. You don’t necessarily need long tube headers, but you need something that flows better than the LT1 manifolds that come on our cars. I don’t think you have any real options, though.

My personal opinion is that you probably don’t want to do any pulley changes without headers. I also don’t think you’ll get the gains Ted got from tuning without race fuel. His gains also looked more impressive because he was getting big time throttle closure on his baseline. They don’t always do that. I’m guessing the cold weather where he is made it more of a factor.

I’ve heard mixed results on the heat exchanger upgrades. I’ve built a number of Magnuson blown (TVS2300 and MP122) setups for me and my friends over the years, and I’ve always found the coolant hoses going to/from the blower to be lukewarm at most. This is with a single, modest sized heat exchanger. Maybe it’ll help more on a road course, but I’ve also heard guys claim that you just end up with more warm water in the system.

Food for thought: my A10 car did a 10.79 @ 132.7 mph in mediocre weather with really just an intake, headers, and ported TB. I also did minor tuning myself. Something like that should be as reliable as stock, with no worries about extra heat or a need for additional octane.

So i did some research and apparently the LT5 has the same exhaust manifolds as the LT4 despite the larger SC.

Also why would cold weather and higher octane effect throttle closure? He said the car was running too rich but then said the car was getting more air than expected (I understand cold air is more dense), but I thought cold and more dense air would help a rich tune, not hurt it, just like adding a CAI seems to help the stock rich tune... or s the high octane the variable throwing this all off?

[BMWM.D.]

Originally Posted by GunMetalGrey

So i did some research and apparently the LT5 has the same exhaust manifolds as the LT4 despite the larger SC.

Also why would cold weather and higher octane effect throttle closure? He said the car was running too rich but then said the car was getting more air than expected (I understand cold air is more dense), but I thought cold and more dense air would help a rich tune, not hurt it, just like adding a CAI seems to help the stock rich tune... or s the high octane the variable throwing this all off?

Well, I think the Z06 has better manifolds and exhaust than the ZL1. So even if it’s the same on the ZR1, it’s better than what we have. 3” pipes, and I think a larger outlet on the manifold.

The reason these cars close throttle in general is that they are trying to hit a target torque level. The control logic on these things is way different than say an LS3, LS9, etc. Cold, dense air means more power (torque). Or at least it should. Problem is that these cars start to limit output when that happens. Just to make it simple for explanation purposes: the ECM wants 650 lb/ft of torque at WOT. In warmer weather, this means full throttle. In colder weather, it would exceed 650 lb/ft at full throttle. So it closes the throttle partially to keep torque where the ECM wants it. That’s a way over simplified explanation of how it works.

That’s why Ted gained so much from tuning in my humble opinion. Running race gas probably made the delta even more severe, as it was probably getting maximum timing (no knock retard). The throttle was probably closed quite a bit. Then once the torque management was reduced via tuning, it now had full throttle and probably more than stock max timing — as I bet Ted bumped it up.

Hope that helps. I’m just an amateur self tuner, so I’m not claiming I know everything. This is just what I’ve seen researching, logging, and tuning my stuff.

[BMWM.D.]

Originally Posted by regnouy37

That’s nuts and a true testament that the highest horsepower #’s don’t always equal the best #s. I’m a firm believer in functionality and efficiency!

How has your cooling been since you added the upper pulley? I’d like to see how your numbers look on Ethanol.

True. I haven’t even had my car on the dyno since I did a stock’ish baseline. I know it feels fast and puts down good track times, so I’m happy.

So far, I’m not seeing much difference in my IAT2 or manifold air temp numbers with the pulley. It’s something like 8% overdrive, so not a huge difference. I forgot to mention I do have a 160 thermostat and lower fan settings. I think this helps on the street and strip.

My biggest problem is octane. The car had ~4.5 degrees of KR on the dyno when stock on 91. I’ve been running Torco in every tank recently, but I need more. Something like E30 would probably work very well.

[GunMetalGrey]

Originally Posted by BMWM.D.

Well, I think the Z06 has better manifolds and exhaust than the ZL1. So even if it’s the same on the ZR1, it’s better than what we have. 3” pipes, and I think a larger outlet on the manifold.

The reason these cars close throttle in general is that they are trying to hit a target torque level. The control logic on these things is way different than say an LS3, LS9, etc. Cold, dense air means more power (torque). Or at least it should. Problem is that these cars start to limit output when that happens. Just to make it simple for explanation purposes: the ECM wants 650 lb/ft of torque at WOT. In warmer weather, this means full throttle. In colder weather, it would exceed 650 lb/ft at full throttle. So it closes the throttle partially to keep torque where the ECM wants it. That’s a way over simplified explanation of how it works.

That’s why Ted gained so much from tuning in my humble opinion. Running race gas probably made the delta even more severe, as it was probably getting maximum timing (no knock retard). The throttle was probably closed quite a bit. Then once the torque management was reduced via tuning, it now had full throttle and probably more than stock max timing — as I bet Ted bumped it up.

Hope that helps. I’m just an amateur self tuner, so I’m not claiming I know everything. This is just what I’ve seen researching, logging, and tuning my stuff.

Thanks for the explanation, it’s starting to make some sense to me.
I think I’m seeing the same throttle closure in another cold temp dyno run


As for the exhaust, the article just said LT4, I’ll look into that more to see if the corvette LT4 has different. Exhaust manifolds than the ZL1 LT4

[EDFHOBBIES]

Seeing this thread made me remember what an Edelbrock engineer told me, I had told him that I'm running a lower 9.XX Ati with a stock upper on my Zl1 w stock blower and needed a combo on my new 2650 that was close so I could limp it to the tuner after I through it to test a stock zl1 fuel system with the new 2650.. He was man that's a tough 1 your spinning yours at almost 24,000 rpms and generating some heat with this new blower your be making the same psi at 14k rpms and moving twice the amount of air! " start with a stock lower and 3.75 and drive easy" was his words.. By the end you build you should see lower of 8.8 to 9.X inches and a lower 3.00 or 3.25 making 800s on 93 only..

[GunMetalGrey]

Originally Posted by BMWM.D.

The reason these cars close throttle in general is that they are trying to hit a target torque level. The control logic on these things is way different than say an LS3, LS9, etc. Cold, dense air means more power (torque). Or at least it should. Problem is that these cars start to limit output when that happens. Just to make it simple for explanation purposes: the ECM wants 650 lb/ft of torque at WOT. In warmer weather, this means full throttle. In colder weather, it would exceed 650 lb/ft at full throttle. So it closes the throttle partially to keep torque where the ECM wants it. That’s a way over simplified explanation of how it works.

That’s why Ted gained so much from tuning in my humble opinion. Running race gas probably made the delta even more severe, as it was probably getting maximum timing (no knock retard). The throttle was probably closed quite a bit. Then once the torque management was reduced via tuning, it now had full throttle and probably more than stock max timing — as I bet Ted bumped it up.

Hope that helps. I’m just an amateur self tuner, so I’m not claiming I know everything. This is just what I’ve seen researching, logging, and tuning my stuff.

Yeah I think you are right, After watching a video by CSP
https://m.youtube.com/watch?v=pJZB_D4VibY
you can see that at about the 12:35 mark when he starts comparing his stock baseline run done the previous winter in cold temps like Ted, then compares it to another dyno run in hot temp with a porter SC but not tune (stock tune) that power dip in the low to mid rpm is gone.

[drfeelgood]

Originally Posted by Can'tHave2MuchHP

I don't know how it could have changed that much with the ZL1's LT4, even with the ZL1's supposed better cooling. Because on the C7 Z06 side, we don't pulley past 9% on stock Manifolds/Cats OR on stock cooling. Going to 15% on stock cooling, even with headers, results in a car that pulls timing after a pull or two in any kind of summer heat. Look up some more information. These cars aren't as friendly to pulleys as LSAs, LS9s, Hellcat engines, and GT500 engines. You have to work around heat and pressure more.

I would recommend:
Intake
9% Pulley or less
Tune

Or
Intake
15% pulley
Headers
Coolant expansion tank
180* Thermostat
TR7IX plugs and heat sleeves
Meth or E is REALLY preferable at this point
And if it's in your budget, any other cooling mods you can throw at it

You're going to be running up against a wall on 93 REALLY quick, most on the C7 Z06 side would tell you not to run 15% on 93 only as you'll pull so much timing it won't even be funny.

I wouldn't go past a 15% pulley on these cars without a Cam/Heads and running it on Meth or E.

So to sum things up, stick with a 2.3 pulley, intake, and supporting parts, and preferably add a set of Ceramic Coated headers to help with temps and pressure as much as you can.

I finally got it all done! Rotofab intake + Tony mamo TB + 2.3" griptech Weapon X upper + Kooks 1 7/8" headers + high flow cats + borla catback exhaust + tune

conservatively tuned on California 91 , doing 615/620

This is as far as I go with power on this car. Thank you all for your advice on my build!

[LS1SS]

Originally Posted by BMWM.D.

I’m guessing here, but I bet the ZR1 has much better manifolds + 3” exhaust. While long tubes are great for their scavenging ability, a lot of the recommendation has to do with flow. You don’t necessarily need long tube headers, but you need something that flows better than the LT1 manifolds that come on our cars. I don’t think you have any real options, though.

My personal opinion is that you probably don’t want to do any pulley changes without headers. I also don’t think you’ll get the gains Ted got from tuning without race fuel. His gains also looked more impressive because he was getting big time throttle closure on his baseline. They don’t always do that. I’m guessing the cold weather where he is made it more of a factor.

I’ve heard mixed results on the heat exchanger upgrades. I’ve built a number of Magnuson blown (TVS2300 and MP122) setups for me and my friends over the years, and I’ve always found the coolant hoses going to/from the blower to be lukewarm at most. This is with a single, modest sized heat exchanger. Maybe it’ll help more on a road course, but I’ve also heard guys claim that you just end up with more warm water in the system.

Food for thought: my A10 car did a 10.79 @ 132.7 mph in mediocre weather with really just an intake, headers, and ported TB. I also did minor tuning myself. Something like that should be as reliable as stock, with no worries about extra heat or a need for additional octane.

on your A10 can i get some more details , I recently purchased one 2017 zl1