[RobZL1]

Originally Posted by clg82

80mm pulley as well, not sure if I mentioned that or not. And thanks!!!

Oh yeah, I figured it was pullied a bit now that you have the corn. Super sweet, dude!

[clg82]

Originally Posted by SOCAL.M6.ZLE

WOW.... fantastic numbers
Do you know how much boost it was making?

Excited to hear your behind the wheel reaction / feedback.

Just asked my tuner, 20lbs.

The tuner replied with “she’s tapped, as far as stock bottom end can take”

[Joshinator99]

Originally Posted by clg82

Well after this last round of installs (kooks, BG, 103mm, pulley) final numbers are 900rwhp, and 800tq. Go to pick it up tomorrow. Super excited to finally be done with this portion of the build and ready to drive it.

Congrats!

[clg82]

Originally Posted by Joshinator99

Congrats!

Thanks josh! It’s been a long journey with the hail damage, other shop being a flake etc….glad i finally found a shop that I can trust.

[radz28]

DAMN NICE!!! It's good to see this combination validated. Another Vendor showed similar numbers on a similar combination, so it's nice to see other show what a stock LT4 can do with a bigger blower, fueling, intake, boost, and E' can do.

Good job on your combo'!!! KUDOS!!!

[KingLT1]

At that boost level the blower is pulling pretty hard on the stock crank. It starts to beat up the thrust bearing. I personally would turn the boost down if you want longevity out of it. Heads/Cam, less blower rpm might hold up longer and make more power, But that is killer power none the less!!

[radz28]

Originally Posted by KingLT1

At that boost level the blower is pulling pretty hard on the stock crank. It starts to beat up the thrust bearing. I personally would turn the boost down if you want longevity out of it. Heads/Cam, less blower rpm might hold up longer and make more power, But that is killer power none the less!!

King' - I was on an 85mm and was seeing about 18-psi in the Winter. I swapped to an 80mm a bit ago, but haven't ran with it in similar weather, but am expecting about 20-psi in the Winter. You're saying it would be better to come back down to the 85mm, to run around the 18-psi then? I calculated I was just a few hundred more blower RPMs than a stock LT5 at 80mm, and know the crank and bearings are slightly improved, so I thought I was okay, but I'm happy to pulley down and put a little timing back into it if this is a big deal. I'm not trying to burn anything up.

Thanks!

[clg82]

Originally Posted by radz28

King' - I was on an 85mm and was seeing about 18-psi in the Winter. I swapped to an 80mm a bit ago, but haven't ran with it in similar weather, but am expecting about 20-psi in the Winter. You're saying it would be better to come back down to the 85mm, to run around the 18-psi then? I calculated I was just a few hundred more blower RPMs than a stock LT5 at 80mm, and know the crank and bearings are slightly improved, so I thought I was okay, but I'm happy to pulley down and put a little timing back into it if this is a big deal. I'm not trying to burn anything up.

Thanks!

Well just when I fall in love with how the car feels……I’m curious his answer as well. They claim they have a lot of cars with this combination but you know how that goes. Now I’m nervous smh.

[radz28]

Originally Posted by clg82

Well just when I fall in love with how the car feels……I’m curious his answer as well. They claim they have a lot of cars with this combination but you know how that goes. Now I’m nervous smh.

I believe part of the problem with the OEM LT4 short block is the half-thrust-bearing they use. BUT - I don't know, practically, to be any help

[KingLT1]

I apologize, I tdidn't realize the 80mm produced 20psi on a stock cam heads setup. Most heads/cam cars make around 16-17psi with that pulley setup.

The LT4 weak point is the half thrust bearing. When you spin a crank driven supercharger really hard it stresses that bearing. The 80mm is probably as small as I would go. Tuning plays a factor too.

[radz28]

Originally Posted by KingLT1

I apologize, I tdidn't realize the 80mm produced 20psi on a stock cam heads setup. Most heads/cam cars make around 16-17psi with that pulley setup.

The LT4 weak point is the half thrust bearing. When you spin a crank driven supercharger really hard it stresses that bearing. The 80mm is probably as small as I would go. Tuning plays a factor too.

Would you feel comfortable sharing a max timing for around 20-psi? 23*? I think I remember a tuner in his YT channel say something like that on a CT5-V running bolt-ons and an X-port around that boost.

[Owl3]

Are you aware of anyone that has had their block remachined for a full thrust bearing, and what bearing was used?

[radz28]

Originally Posted by Owl3

Are you aware of anyone that has had their block remachined for a full thrust bearing, and what bearing was used?

LME and those kinds of big boys do that, if I recall. Probably, any, competent machine shop should be able to.

[KingLT1]

Originally Posted by radz28

Would you feel comfortable sharing a max timing for around 20-psi? 23*? I think I remember a tuner in his YT channel say something like that on a CT5-V running bolt-ons and an X-port around that boost.

TBH I haven't tuned a SLB LT4 at 20+ psi of boost. Most ain't trying to party that hard and I don't really mess with port injection which is the only way to get a stock heads cam car to have enough fuel for that. But I do think 23-24 degrees should be no problem on E85. The amount of boost or timing isn't really the issue. It's the supercharger pulling on the crank when it's being spun hard. Back in 2017-2018 guys like Andrew @ CSP were saying anything above 800whp out of a stock blower setup was rolling the dice far as thrust bearing failure. Then porting programs extended that number to 900 since you can make more power without increasing blower speed, the 2650 even further, and turbos even more. I just seen the 20psi and that came to mind but I forgot he was stock heads/cam. SLB will show 3psi more boost at the same pulley ratio because it's boost stacking vs a heads cam car. Really just need to know the actual blower RPM. Either way I think the OP tuner is spot on.... It's near it's limit. I believe Mike Sitar made like 900+ SLB in his Z06 but said he didn't plan to leave it there for longevity sake. I can't remember if that was with the 2650 or X port. I know he swapped back and fourth when testing port injection. on his car.