Vortech on Stock Pistons???

[Davin]

Okay, to begin with, yes the Ghost is skeptical. I saw that Jegs was advertising a Vortech kit with 6 psi for the 94-95 GT. I called their tech support and talk to a guy who believe it or not actually did sound somewhat knowledgeable. I asked him if Vortech required a piston upgrade for the kit. He said that the kit could be installed and run safely, even with the hypereutectic pistons. Apparently it has something to do with why it is a 6psi kit.
Opinions…do you buy it?

 

[S/CBlack95GT]

With no detonation the stock pistons will last a long time. I am running 11psi with no problems. Many guys are running 14-15psi and making 500+rwhp with no problems. You just cant have any detonation.

 

[Davin]

so what's the best way to avoid detonation???

 

[S/CBlack95GT]

so what's the best way to avoid detonation???

Run it rich and keep the timing low. It is better to kill 10-15rwhp and be safe than to risk popping something. Im running a 11.0:1 AF/R and only 17 degrees of total timing. I could probably make 430+rwhp, but it just isnt worth it.

 

[94GTLaserRC]

so what's the best way to avoid detonation???

Agreed with Shaun's replies.

Main causes are:

Timing (too much)
A/F ration (too much air, or lean)
Heat (hotter the worse)
Octane (higher is better)


I think the "average" boost that guys on this forum with Vortechs run is around 10-11#.

You have to kinda use your judgement on balancing the above factors. If you run a BTM (comes with kit) and the temp outside is hot, you have to use the BTM to pull back some timing. When it is cool, you can "afford" to run a little more timing.

Always use the highest octane available in your area. If you run the car at 11:1 AFR, like Shaun, you are in good shape. You "could" run 12-12.5:1 and a little more timing to get 20-30 more HP, but is it worth it?

Lots of factors involved...Good Luck.
RC

 

[VibrantRedGT]

My 60,000 stock short block couldn't handle 12-14psi. Weak link is 5,7,8 cylinders. My car ran worse in colder weather, go figure. Not into the forced induction scene anymore. Way too many factors.

Keep the total timing low, over inject the motor, MSD6BTM is a good ignition tool, dyno tune is required and a tuning device is a great investment.

 

[94GTLaserRC]

My "guess" on the problem in colder weather is that since you take in more air, you are more likely to run lean, esp if your AFR is borderline anyway. Shaun has enough "buffer" in his ratio. My friend ran borderline, and he said he had to be really careful in colder weather because of the AFR getting lean.

My car runs pig rich, so IM not worried about the temps.

Agree with Joe though about "way too many factors". Im gonna be following in his footsteps hopefully in the next 1-2 years and build a nice 347 N/A combo.
RC

 

[Davin]

Thanks for the replys guys. I think the "too many factors" issue is interesting. I was on the road toward a 347 bulid when a $2400 Vortech stopped me in my tracks. My current intake/head/cam setup is already geared toward a SC so I was thinking I could have as much or more hp with 6 psi on a 302 than with a mild 347. The 347 would require a good deal of porting, valve work, replace oil pan, filter, upper intake etc. The list was starting to get so long that I figured hanging a SC off it would be a lot easier.

 

[94GTLaserRC]

Thanks for the replys guys. I think the "too many factors" issue is interesting. I was on the road toward a 347 bulid when a $2400 Vortech stopped me in my tracks. My current intake/head/cam setup is already geared toward a SC so I was thinking I could have as much or more hp with 6 psi on a 302 than with a mild 347. The 347 would require a good deal of porting, valve work, replace oil pan, filter, upper intake etc. The list was starting to get so long that I figured hanging a SC off it would be a lot easier.

A 302 with 6psi will not be as quick as a well-built 347. Now having said that there are other factors...I dont think ANY of us has put on a S/C without spending tons in "supporting" upgrades...fuel system, injectors, intake, tuning device, etc. If you go back to your original ? and just want a "quick" power adder, then yes, it's ok on the stock pistons and will get you quick power. If you need to do all that work to get a 347, then Im assuming youre not gonna wanna just "hang" a S/C on there..you are gonna wanna do other work.

My AODE with Vortech, stock heads and cam, and upgraded everything else, probably is a high 12-second car at best as it sits. Most guys with h/c/i and power adder on a 302 are around 400-425hp and run low 12's (on average)

A good 302 combo 'can' be good for high 12's and even low 12's (as Killer canary has proven).

Think what a good 347 combo can do Remember 375hp with a Vortech is nowhere near the same as a N/A 347 with 375 hp.

GOOD LUCK!
RC

 

[VibrantRedGT]

Good point Rob.

When we went the supercharger route we bought. MSD6BTM, wires, 70MM TB, MAF calibration (for me at least), bigger injectors (42's for me) and more. We spent $2000 on the blowers and another $1700 in supporting mods and installation.

 

[94TURBO5 O]

Joe and Rob you need a turbo!

Davin I ran 12#'s with an S-Trim, 10#'s with a KB and now 9#'s with a T-66 turbo on stock pistons. 6#'s is nothing so don't be skeered of that kit. Go turbo and you'll be much happier, IMO.

 

[VibrantRedGT]

JR, no forced induction for me. I would love a turbo as I've owned a 500HP Grand National. However I'm dropping in a 347 with some nice goodies. Blown headgaskets, finicky EEC issues, worrying about boost and A/F ratio's are the thing of the past for me.

 

[Davin]

JR, first fo all, your car is sick! Very nice. I'd love to go the torbo route but with a 7mth old, its too much coin.

All, interesting comments, I thought that the kit came with injectors but I just took another look and it does not. It does come with a t-rex fule pump and 12:1 fuel management unit. I have a TwEECer already, so that's covered. This isn't a strip car (in fact I've never been), I just want to get her to about 400rwhp and was thinking this might be an option. I also thought at 6psi I would be less likely to blow a head gasket.

Anyone feel comfortable predicting what my current set up might crank out with 6psi? 9psi?

 

[haulbalz]

nevermind

 

[94GTLaserRC]

Anyone feel comfortable predicting what my current set up might crank out with 6psi? 9psi?

You will NOT need to worry with 8#...dont even think about 6!

WIth your current mods and Tweeked, you can make 400 to the wheels, but if youre going that route, I would sacrifice a few ponies for "ideal" safety conditions.

I would however fork over the extra $$ for injectors and fuel pump and screw the FMU...it's too hard to tune with the twEECer and on a dyno with that (hard to know "exactly" how the FMU is controlling everything)

Good point Rob.

When we went the supercharger route we bought. MSD6BTM, wires, 70MM TB, MAF calibration (for me at least), bigger injectors (42's for me) and more. We spent $2000 on the blowers and another $1700 in supporting mods and installation

WERD!

 

[Davin]

thanks for the take