Hi all, I've got a quick and simple question. If I were to decide to twin charge my '06 SS/SC (2.6" pulley & 60# injectors), what size turbo should I go with? Thanks for any input.

 

Your wanting to run a Turbo charger AND the supercharger???

 

what size pulley should you go with? 2.6 seems a bit low for a twin charge setup. I would think a 3" would suffice.

 

dont they put a bigger pulley then stock??

 

ZZP may have some info on their twincharged Cobalt. I think they went close to the stock pulley size but I'm not sure.

 

I have no Idea.. lol, but I would go with the 3" if it was my car. I mean its not a stock pulley, but still can make good numbers if done right, and can defiantly outlast a 2.6". This is just my opinion though, he only has #60's and could risk maxing them out at higher rpms because of the 2.6 AND the turbo if assuming he got tuned... this is just what I would do though.

 

The size of the SC pulley depends on what kind of Twin Charge system you are going to use. You need to do a lot more research.

https://www.cobaltss.net/forums/sear...archid=1774187

 

2.6" you will overboost like crazy.

I am running a GT3076r, with a exh. .63 a/r and going to go with a 3.5" pulley to start off with. That may not be enough, if it is not, I am going to have to get the .82 a/r or the 1.06 a/r exh housing.

I heard of a guy that had a twincharge that had a 2.8" I think with a .55 a/r exh. on the turbo and he hit 30 psi at 2000 rpm. That is not good! haha

this...

 

I depends on how you setup your Twincharge system. A 2.6" might not be a bad idea if you are running the by-pass setup ZZP uses. They by-pass the SC at 4k once the turbo is spooled.

If you are running a compounded system then a 2.6" will be way too much. A 3.35" (stock) or 3.5" would work just right.

 

Going back to the stock pulley isn't a problem. I'm lookin' at turbos with .50 compressors and .63 turbines. I wasn't sure what the best pulley/turbo combo would be though. I was thinking that the twin-charge would probably work like a two-stage compressor and compound the boost pressures once the turbo spooled, but I wasn't sure. I really don't want to go over 20 psi., but I've been thinking of shooting for the 23 psi mark. Any suggestions would be appreciated. There's no one around my home town that has any experience with twin-charging, or LSJ's for that matter.

 

Well I will say that you will need a larger pulley, stock or bigger with that size exh. Like I said I am using that same exh housing and running a 3.5". I will not be compounding the boost, I didnt think that the roots style blower could compound but I am not sure now. I will be bypass the blower as the turbo gets to full spool. If you have no experience read up and talk to zzp.

 

Isn't it easier to twincharge than convert to all turbo? That is what I figure....

 

Not really. There is not much difference other than not having to take your blower and im off and putting a new im. Tuning on a twincharge charge is different and you need "boost controllers" for the SC vac lines running to the blower. Little more complex imo.

 

Ya'll keep the input comin'. This is just part of my research strategy. It's all appreciated.

 

there in no need for a smaller pulley then stock smaller pulleys on a twin charged creates way to much heat

 

ZZP uses the stock pulley size with their twin charge kit, a bigger pulley than stock can also be used. i know a decent amount about their twincharge kit from some first hand experience driving it and watching my buddy hassle with it all the time

with a massive FMIC...iat2s will love you, but smaller than stock pulley isnt necessary as you said

 

ok let me explain this a big fmic wont do anything the supercharger is heating up the intake temp AFTER the fmic the best a fmic can do is bring the temp down to ambient temp so it would be like the turbo is not there but the supercharger will still heat is up and the stock cooling system doesnt work as well with a big fmic in front of it

i hope you can understand stand that i am pretty tiered

 

Another question I've got is what's the max "safe" boost that the LSJ bottom end can handle?

 

i get what youre saying and that makes perfect sense, im saying from what i saw first hand, my buddy had the ZZP twincharge kit, stock pulley size and the biggest FMIC they had to offer...iat2s around 120 all the time, and he had no other cooling mods

um well...i know he had his boost setting at 25psi and held up great...several times turned the boost up to 28psi, probably not recommended but he pushed the limits lol

 

yeah see 120 with stock pulley with full cooling mods and a 2.7 i only hit 115 on the dyno with a 3rd gear pull

anything smaller on a twincharged car will create to much heat

 

Thanks. That's helpful info.

Also, anyone know what the cost of HP Tuners is now??

 

yea i understand what youre saying, but if youve ever driven a twincharged cobalt or any other twincharge setup... i literally involuntarily blurted "OH ****!" as i stepped on it in 2nd gear...no need for a smaller pulley cuz it would be pointless and generate more heat as you have said lol

ZZP frowned upon him turning the boost up higher than 23psi though lol

 

lol and for people that want to pulley down with a twinchargered car the supercharger is not there to make power just to spool the turbo

 

What were is dyno numbers at 25psi?

 

406whp 372wtq

exactly, and stock pulley size on the blower fully spooled the 57mm bullseye extended tip he had by 3 grand

http://www.youtube.com/watch?v=nLyOm...eature=related