Modifications to the L92

[Jason in DLH]

Found this great write up on modifying the L92 engine:

https://www.onallcylinders.com/2018...-expert-advice-l92-mods-maximize-performance/

 

[91RS]

That is great information all in one place. Thanks for posting this! I might need to go ahead and get injectors for mine, I think I will be right there at the limitations for the stock injectors with the cam I have waiting to install.

 

[Joseph Garcia]

Great info! Thanks for sharing.

 

[Jason in DLH]

That is great information all in one place. Thanks for posting this! I might need to go ahead and get injectors for mine, I think I will be right there at the limitations for the stock injectors with the cam I have waiting to install.

What Cam did you get?

 

[91RS]

Comp Cams 156-401-13. I have an 08 so based on their guide I could be right there at the approximate 390whp limit of the stock 30 lb. injectors. My tuner said we could give it go and see but he's gotten slammed with work and I wonder if I should go ahead and get L96 injectors and be done (they're cheaper than the LY6 injectors) just so I don't have to worry about having to take it back after an injector swap.

 

[Jason in DLH]

Since it sounds like you’re going to change the injectors anyhow...mind as we’ll go with bigger ones and throw a supercharger in the mix.

Did you have to get the Phaser Limiter and new valve springs with the new cam?

 

[91RS]

I’d love a supercharger but I wouldn’t want to put a supercharger on a 150k mile engine without freshening first. So mild cam it is. Yes, I did also get the phaser limiter and new valve springs (PSI 1511). I’m also doing a CHE Trunnion, hardened pushrods, Melling oil pump, LS2 HD timing chain and guide, ARP bolts, and using the LS3 heads off my SS.

 

[mikeyss]

I’d love a supercharger but I wouldn’t want to put a supercharger on a 150k mile engine without freshening first. So mild cam it is. Yes, I did also get the phaser limiter and new valve springs (PSI 1511). I’m also doing a CHE Trunnion, hardened pushrods, Melling oil pump, LS2 HD timing chain and guide, ARP bolts, and using the LS3 heads off my SS.

Before you put those heads on, check the valve seals. My buddy who's letting me do my engine build in his shop did some research and found the 823 heads are loosing their valve seals, especially the caprice 9C1 cop cars that are getting miles on them. If you have 821 heads, I don't think they have the same issue. Here is my head with half of the valve seal jammed into the valve.

 

[91RS]

I can’t remember which number they are off hand but they only have like 4k miles on them. They came off my 16 SS and have been in the attic for 3ish years. My truck currently has the 823 heads on it, I just looked.

 

[mikeyss]

I can’t remember which number they are off hand but they only have like 4k miles on them. They came off my 16 SS and have been in the attic for 3ish years. My truck currently has the 823 heads on it, I just looked.

The guy told me he's seen 12 cop cars lose a valve seal, and his personal use Escalade did it twice. But it's only been 823 heads that do it, and they all had higher mileage on them. I'm replacing mine with TSP in house made heads so that I don't have to worry about this again.