clintster77

One Idea I have been kicking around to get more for the money is to buy 10.1 compression forged pistons pistons for $ 800 and install myself Then later buy the 8psi vortech tuner kit that runs about $2976.95 . I would also have to buy a tune or take it to be tuned to get the most out of the custom setup .

This would be approximately the same hp as the 10psi vortech kit but with a bit of a different attitude in the throttle response department . But I would have forged pistons and a custom tune for less than $4000.
Am I missing anything ?

How to figure out your efective compression:
(Boost / 14.7) + 1) x Stock Compression = Effective Compression

So say that you are running 8.5:1 compression pistons. To get an effective compression of 18:1, you are going to need to run approx. 16.5 psi of boost.
If you were running 9.5:1 compression pistons, then you would only need to run about 13 psi to achieve the same amount of power.

edgespeeder06

I have a custom built 8.8 rear with 3.73s and 93 Performance, and its one hell of a v6, only thing i believe a v6 should have came with was a 8.8 rear with 3.31s or bigger, not a 7.5 for the purpose of holding supercharger power like you all mentioned. I had the chance to buy the xcharger for $2500 when I bought my custom rear for $600 from a friend but didn't have the cash upfront but now I wish i had taken money from somewhere. Just sucks to have to pay $3600+ to get it now new. Don't know what to do yet.

tx_zstang

The 8psi kit is the base kit with no intercooler. The 10psi kit has a water-based aftercooler. The only difference in the base setup is the size of the pulley that comes on the Vortech. The 8 psi has a 3.6" pulley, and the 10 psi has a 3.25" pulley.
It is much better to run an intercooler (actually, it's an aftercooler since the cooler is after the supercharger, but everyone calls them "intercoolers") if you can afford it, and with the cooler air, you can run more boost and more timing for more power.

I purchased a 8psi tuner kit to get the supercharger unit and parts, then got a smaller pulley, and built my own air-air intercooler setup. And of course a custom tune to fit my setup.

If you aren't sure about whether to upgrade the 7.5 rear end or get a 8.8, there's really only 2 choices:
1) put a Detroit tru-trac in the 7.5 in place of the stock carrier (do NOT mess with a trac-loc, they aren't strong enough either)
2) put in a 8.8

If you do not plan on making over 300 hp and do not plan on running sticky tires, then you could get by with a 7.5 rear end with a trac-loc.
The problem is, with tires that grip (like slicks and drag radials), with the extra power, the spider gears in a trac-loc in a 7.5 rear end can break. There's plenty of pictures of the carnage that can occur.

clintster77

Can you easily switch between the two pulleys ?
If so I would consider buying both pulleys with the base kit and invest in a water/alcohol injection to use at the track with the 10psi pulley on it.
Put the 8psi pulley for when I don't want to keep the reservoir full of 50/50 water/alcohol fluid.

One good thing that can be an advantage when water injection is introduced is that it also takes up room in the cylinder and produces a slightly higher compression ratio while still carrying out heat at the same time . The alcohol half of the mix adds power too.

Maybe even keep the original plan of putting 10:1 forged pistons in it .
Wow 10:1 pistons and 10psi boost with water/alcohol injection sounds Trick .

.boB

Sounds risky. That gives you a boost compression ratio of 16.7:1

Of course, compression ratios just get you into the ball park. What you're really interested in is effective cylinder pressures. That takes in to account static compression ratio, intake valve closing point, rod length, chamber size, etc.

If you want to use pump gas, you need to keep the pressures below about 200psi. With water/alcohol injection and conservative timing, you can go to about 210-215psi. Anything more than that and you'll need race fuel to keep the engine alive.

There's some good calculaters here: http://www.rbracing-rsr.com/harleytu...m#calculations It's a Harley site, but the calculations work for any 4 stroke engine.

afixer

hey guys,

i have the cali kit but am using the AFE air box that i prototyped for them a few years ago. i have had the kit for over 35000 miles now and other than replacing the drive shaft that we folded in half on the dyno when we installed it i have not needed to replace the stock rear.

but i do now have a t-loc rear and thats it. i would have installed the 3.73's but at the time i did the rear Dave was going to use my car for the carb cert and they needed the stock gears for the test.


so my set up is.

X-charger 001
3" pulley but i run 2.8 at the track and yes it just pulls off.
auto trans
t-loc with 3.31 stock gears
AFE Cold Air Kit
Custom Dyno Tune 282 hp

best 1/8 mile is 8.92 but that was peg leg and before the dyno tune.
i am not really a track freak i just went to give some times so others would know. others have tweaked the x into the 12's and 13's respectively as well as wining many race classes . the x is a dam consistent runner for bracket racing.

killdar

^^so an xcharger would be fine w/ everything else stock just tlock added w/o doing any damage

afixer

you can go to a car rental agency that sells used mustang v6's bolt on a x-charger and have a hell of a time. i only installed the t-loc because with the x . you burn out so much the extra traction helped.

clintster77

10:1 with the 8psi boost comes out to a EC ratio of 15.4:1 ( street setup )
10:1 with the 10psi pulley comes out to an EC of 16.8:1 ( track setup with alcohol / water injection )

That dose seem close to the edge but the 10psi with intercooler and stock (9.7:1) non forged pistons ( vortech kit ) comes out to a EC of 16.3:1


Hear is another good read about compression ratio link to good article on compression

rygenstormlocke

I think Mike is spot on. Also, just to add to that, if you stick with a 7.5, I would get a girdle cover. I went with the LPW piece.

I think the reason why my 7.5 w/Tlok held up to high 12 second passes on DR's was due to the LPW girdle. It continued its life on two other cars before shredding though. Trutrac on the 7.5, or go 8.8 IMO.