LT4 blower on Stingray - sound off on boost levels
 

There are a few threads about the LT4 blower on the LT1 cars, but I am curious where everyone has ended up in terms of boost.

If if you have the LT4 blower on your LT1, which mods have you done and how much boost/power did you end up running?

My LT4 blower is on its way to Jokerz to be ported. My intent is to start with the stock Z06 pulley and to have the ATI lower pulley (stock size). As I want to up boost I will leave the upper pulley and simply change the lower pulley.

I know on an unported LT4 blower I saw @onebad1lE had 740whp on the 15% overdrive pulley.

What did you do? Anyone running on the stock LT1 fuel system?

The stock LT1 fuel system won’t support anywhere close to 740rwhp and neither will the pistons. 10 psi with LT4 fuel parts is about max in my opinion. Mine made 613 rwhp with this combo.

Yes. I know. The stock LT1 fuel system will be dropping off by 575whp. I am personally trying to figure out if I should stick with the stock LT4 pulley, or go with a bigger pulley. But I am curious what others have done.

So you were running the stock LT4 pulley and were at 10psi? Did you have any other mods to go with the blower? Was your blower ported?


Thank you for the info.

Stock size pulley on the SC. LT4 pump and injectors. Wet sump car so needed an ATI balancer, billet spacer, and 5% OD lower drive pulley to get 10psi.

Awesome. So most likely the stock pulley and overdrive pulley in stock size will probably make about 8psi and 550whp which will be just fine on the LT1 fuel system.

Where did you get the ATI setup? It’s a hub, balancer and lower blower pulley all bolted together, right?

Yes on the balancer. It was a complete kit from West Michigan Auto Tech.

https://west-michigan-automotive-tec...myshopify.com/

I got 630rwhp ish on 5% od (around 9.5psi) and lt4 pump/injectors. Bought everything from west Michigan Automotive which I highly recommend.

Did you change something after the post you made showing 620/630whp? Are you saying you had 730bhp (engine HP)? 9.5psi isn't going to make over 700whp on a stock LT1 without a bunch of other things...figure that 7-8psi is about 550-575whp. You will pick up approximately 30-40whp for every pound of boost..

Whoops that was a typo.

Damn. I was hoping I missed something. Truthfully, now that I am into my Vette build, It looks to be exactly like my Camaro build. I am seeing the same path...but since I went with the LT4 blower I am going to be a bit more scaled back.

I am am pretty much settled into my path now. I am going back to Jannetty Racing and going through the similar path with the LT4 ported by Jokerz as the main difference.

Otherwise, my build will be as follows:

stage 1:
1. ported blower with
2. stock Z pulley and
3. replace lower with the ATI setup for wet sump...stock size.
4. Front crank seal
5. Catch can and vent
Expected outcome: 550-570whp @8psi

stage 2:
1. Lt4 fuel injectors
2. Lt4 hpfp
3. Voltage booster or DSX aux
Expected outcome: foundational, no power change

Stage 3:
1. Forged rods/pistons
2. JRE smooth idle cam (I have rough idle in my Camaro)
3. E85
4. Swap to 15% overdrive pulley
5. Lt headers
expected outcome: 720whp on about 8-9 psi completely safe and fun...

I really wish I could skip the LT’s because that’s always the point where my car gets too loud. . .

Im at 12psi at about 670 on 30% E. and i have a 2.4 upper. LT4 fueling and a low side pump.

That makes sense. I think I might even go with forged rods/pistons and fuel...then just swap to the 15%overdrive pulley so I can run in the 700whp range with the stock cam, manifolds, in-tank pump with e30-40. That might be the best bet for my daily driver to keep the noise level reduced.

I'm going Cam and pistons and rods, next. I know I'm playing with fire right now.

I had a standard blower, x pipe, LT4 pump/injectors standard pullies and was at 586rwp. I would suggest getting the pump and injectors which will save from top end issues.
Just installed a ported blower with 103mm bore, plan to get the LT5 98mm throttle body and retune - should get up around 620 which will be my stopping point (for now). I don't want engine issues and since I really don't track, just punch it now and then am happy, oh also got the expansion tank and catch can installs. SAFETY FIRST! You observant ones will notice the belt not attached, this pic was taken while putting it all together!

https://cimg3.ibsrv.net/gimg/www.cor...bc6634a1b8.jpg

i am really torn on this one. I have the blower ported by Jokerz...I am trying to figure out if I add the fuel, forged rods pistons...I am planning stock upper and 5% OD lower. However, if I go forged, I will add the 10% OD lower.

I ran 12 pounds with 2.31 upper pulley. 670whp. Held just fine.

I don’t like the idea of running over 600whp without being forged. It’s just a personal thing. This is where I lost it on the Camaro too.

Since I was adding forged, I added a cam. Since I added the cam, I added LT’s and got rid of cats. Since I added the cats, got rid of headers and had forged internals, it made sense to add e85....damn slippery slope. Next thing you know my daily driver is making 800whp and is not close to reasonable with street tires.

I want to play this safer. The Vette is my daily driver. I am thinking that I can skip the cam and LT’s...just go forged with 10% OD pulley and e85 (probably e30-40 with stock cam). That should be good for 700whp but will largely feel and sound like stock unless you hit it. Maybe I could save some money by just going drop in pistons since I am staying under 800whp.

I will try to get some pictures this weekend of my LT1 Maggie setup and also get some pics of the ported LT4 blower just for fun.