Hey vendors we need someone to make a 2.85" pulley that fits the GM stage 2 hub.
Can someone please make this for us? It would be greatly appreciated by all!

A 2.85" pulley will keep the 42lb. injectors just below 80% duty cycle @7,000rpm.

Tune Time Performance link. Click on the links next to the Cobalt.

http://www.tunetimeperformance.com/

Here is his thread.

https://www.cobaltss.net/forums/tune-time-performance-115/dyno-results-35070/

UPDATE!

Hey guys Jim@Tagracecraft can make us a 2.85" pulley but we need 10 people.

1. Me
2.
3.
4.
5.
6.
7.
8.
9.
10.

 

haha i knew you would be making a thread like this, good luck!

 

80% duty cycle?

 

Why not just use the 2.8

is .05 gonna make that much difference?

I am gonna run the 2.7 once i can get tuned

 

You know it. Thanks bro.

Yes sir. Just under 80% @7,000rpm

 

Whats the duty cycle with a 2.8 pulley?

 

Yeah it does make a difference. A 2.8" makes about 83% duty cycle and a 2.7" is up near 92%. Anything above 80% and the injectors can go static. It's just a safety precausion.

About 83% duty cycle @ 7,000rpm

 

83% in all honesty I wouldnt worry about. You will still be safe it snot like you are going to be holding the car at 7,000 rpm for a exteneded period of time.

 

i read a 2.8 made 100 percent at 6100 rpms last week?? lol

 

Yeah I don't know who that was but I trust Tune Time Performance.

 

Reading and actual experience are two different things. I run a 2.7 and 42's.

 

Did TTP use GM injectors? I have seen HPT logs with GM injectors and a 2.8 showing over 100% flow. My theory is that the Stage 2 injectors are 42 lb/min AT 60 PSI. The aftermarket injectors are all rated at a standard fuel rail pressure of 43psi. So the aftermarket 42s actually flow more. But to be sure you need to take YOUR car there and have YOUR car logged for this.

 

And what's the duty cycle of your 42lb.ers @7,000rpm with that 2.7" pulley?

 

ya i read the graphs and info and his data logs, 2.8=100percent at 6100 rpm....

 

just a question but how would either flow better if they can only send out 42.5lb/min. pressure is one thing but forcing something through a channel that only allows for a certain flow rate is still only going to yield that flow rate. This could be applied to water entering a tube from a larger tank. while the pressure before the tube would be higher than in the tube it can only flow to its maximum regardless of outside pressure until it breaks.

 

They were gm injectors. The link is at the top.

 

this would have had to have been before the updated tune and he was likely getting the lean false lean issue

 

you have a link to the graph? i dont see it unless im misunderstanding

 

interesting....

 

Where the heck did it go? This site is weird sometimes, let me go fix it. BRB!

 

Ok all set!

The link is there on the first post now.

 

In his post with the 2.8 he said they only saw 78-82%. You will be ok with that or am I missing something here?

 

Yep and that's from 5,500-7,000rpm. I want a 2.85" to stay just below that 80% mark @7,000rpm.

 

i would love to think we would be ok and having the injectors go static for only a second isn't going to do too much if any harm to anything specially since the next thing you do right after it goes static is change gears and put them back down to less duty

 

lol i said duty