i was planning on getting tuned soon until i heard i was getting an overdive pully from c/a from my girl. i will be running a 2.79 pully with the overdrive which they say adds 1# of boost roughly. what kind of boost #s will i be looking at? and will i need any further cooling other a C/A dual pass he and hatrickstu's cooling mod, cuz those i have? And yes i have 60's.

hp mods are=v2 header, 3 inch dp w/ cutout, 2.5 cust.exhst, 3 inch intake.

 

I recommend methanol injection. As far as boost you will see about 16lbs give or take. Remember boost doesnt always = power. If you can, watch your iat2's. But as I stated, you should REALLY think about methanol injection.

If you plan on doing back to back pulls, you will need meth injection or atleast water injection. Who is doing the tuning?

 

im already at 16psi with gm s2 and 2.99 pully

 

You should be closer to 16~17 if your on that big exhuast, on stock exhuast maybe more but not with what you are running.

 

yup, I have a full 3 inch exhaust, with a 2.8inch pulley and I see slightly above 16psi.

 

so i should only see a 1# of boost dropping down 2 pully sizes with the over drive?
cuz right now at 5000rpms i hit 16 psi in jersey we tend to see alittle more boost cuz we are at sea level

 

you sure you have a 2.5inch exhaust and not a 2.25inch?

and what pulley are you currently using?

 

yea its a custom 2.5 stainless tig welded with a 18 inch magnaflw no resinator

 

and the pulley size you are currently using?

 

gm s2 w/2.99

 

Well if you are for sure seeing 16lbs on the stage 2 tune, then you will probably see 17lbs with the 2.8inch pulley. Possibly 18lbs, but I doubt it.

 

thats what i was thinking, i 100%on the 16 lbs at 5000 rpms we see more boost at sea level

 

We've never had any luck with anything other than 100% methanol with boost on LS1's. Do people get away with a mix with these engines? Bob

 

......I don't think you understand the point of methanol injection for our cars.

For us methanol injection is used for 2 things. MAINLY to cool down the iat2s. These cars can run 100% water injection, however if your custom tuned, I recommend a 50/50 mix of meth and distilled water, or just windshield washer fluid.

The water cools the car, the methanol acts as an octane booster and raises the octane. This helps with pre detonation and knock. So I don't understand why you guys HAVE to run 100% methanol unless you guys are advancing the timing so far, and are tuned so aggressive that if you don't have the extra octane you screwed, which wouldn't make a lot of sense.

My tune is pretty aggressive, if I run out of methanol and go wot *wide open throttle* it would result in a blown #4 piston more then likely same with many others here. Either way, I think I explained everything well enough for you to understand it.

I am sure ls1's are also capable of running a mixture of methanol and distilled water. Make sure it's distilled water and not pure water. Pure water is corrosive to engines, distilled water is not. If you have any more questions let me know. Hopefully this helps you, and don't take this as a personal attack, its just friendly advice

 

I didn't think they were doing overdrive pulleys on the lsj but okay. It would be more beneficial to get the lighter crank pulley but to each their own. It's not an overdrive crank pulley I'm guessing.

You don't need any other cooling mods in fact I'm not sure what other one's exist (meth, nitrous, co2).

edit: apparently you're talking about overdriving your crank pulley...I'm going to go out on a limb and say...that sounds like a bad idea.

 

the overdrive is for the LSJ, underdrive is for an N/A motor. im trying to feel out this idea of the overdrive, it seems like a good idea less diming of the head lights, 2lbs lighter, and one 1lbs of boost. what is the down side other than heat? would it be better just to do a stock size swap?