So my buddy bought a 96 lt1 completely stock engine w/ some bolt ons. It has a Powerdyne SC on it putting 4.5 psi out. He was asking me what he could do to get some more power out of it because it is only running a 13.2 in the 1/4. I dont know much about boost, so i thought i would post the question on here for all you boost guru's..
I did tell him he would be better off to get rid of the Powerdyne unit and go Procharger or vortech..i dont even think his car is intercooled, but he says he doesnt have the extra cash to buy a new head unit so i was hoping you guys could give me something to tell him other than a big old laugh im pretty sure it is using stock injectors as well..i have no idea what is keeping this thing from detonation..how much boost can the stock lt1 hold? what # injectors should he use, pulleys, etc? any help would be great, thanks

 

i wouldn't go any higher on boost without without either an intercooler or some sort of meth injection kit.

Some guys get away with 6-8lbs on stock but its a time bomb no matter what. If he isn't thrashing on it he could prol get a lot of time out of it. But clearly running a 13.2 isn't good, but what was his speed? Thats the real story. He could just totally suck *** outta the hole but still be trapping a lot higher.

He needs to get it tuned ASAP to make sure its not running lean or pig rich or whatever. If he doesn't have money now he's going to be SOL when he blows up the motor for trying to save a couple hundred bucks.

 

1993Fast_Z:

If it hasn't been tuned for the boost then the stock tune is retarding the timing severely from ~4k on up. Stock (24#) injectors will be at or near a 100% duty cycle above 5k. It should use plugs 1 range colder and tighten the gap (.035 - .040) too.

 

Thanks guys..i definately figured he was close to maxing out on his 24lb injectors..would you think 30# injectors would cover it being he has that PwrDyne 4.5 psi w/ BBK shortys?

 

1993Fast_Z:

He'd probably see a max 75 - 80% injector duty cycle. It wouldn't leave much margin If he wanted to do a cam upgrade.

 

<<< Sell it, buy a LS1, add cam and nitrous. problem solved

 

if he wants to try and have it not blow up on him I would do the following:
36 or 42 lb injectors
full exhaust---Long tubes with a 3 inch ory/ True dual.he needs good exhaust
3.42 gear-3k stall if auto, 3.73 m6.
1.6rr's
try to only run 5psi.
Dyno tune. Maybe meth if he has a budget for it.


But you hit the nail on the head, why try to make a powerdyne car run quick?? It will only really be a low 12/high 11 car no matter what you do. The blower limits all the fun, sell it for something real.

 

i would assume hes using some type of FMU to try and make up for the lack of aftermarket injectors. But as the others have said, a tune and the correct fuel injectors would make all the difference. What type of drive train? m6/a4? What gear? What kinda tires? i mean if hes on a stock street tire with a stock 3.23 gear (or whatever his car was built with) i can deffinitly see a 13.2

 

There was someone selling a vortech s-trim for 1550. I got mine for 1650. I ditched the powerdyne for the s-trim and was nothing but happy. I lost about 150 on the deal, but I had alot of upgrades to my kit and it had new bearings in it, so i really lost that too. In the end, i was still happy to make the trade-up, despite losing about 250. My kit came with 7" crank pulley and 2 s/c pulleys and a custom hard intake pipe.

That being said, anymore than 7 psi on a stock lt1 WILL take out your ring lands at a moments notice if you run lean or get into detonation of any kind. The pistons just cant handle the heat, trust me, I know. I can send you the pic of the side of the piston melted down from a lean spike probably caused by an injector that locked up because they were too small.

 

I ran my powerdyne with 30 lb injectors along with the FMU for 20,000 miles on a stock engine with 100,000 miles.
I also had Madwolf supply me with a tune.
The 6 lb pulley only gave me 4 lbs of boost so I ran a 9 lb pulley that gave me 6 lb.
It was all great fun but eventually the engine just wore out at 120k to the point that it would put out plumes of oil smoke and stink up the interior if you got on it at all.

Now it's a Golen 383 built for boost with an M6 conversion.

I guess I should update my sig.
The Powerdyne which is completely silent, is still on it but now only puts out 4.5 lb with the 9 lb pulley on a 383.

I bought a Procharger set up for 12-14 psi off a board member but after spending a year and a half on the engine and transmission I'm just going to drive the car and get used to it again for the summer season.

At some point it comes time to actually drive the project.
I'll save the Procharger for next year.

I'd go with a 9 lb pulley as I had no problems on my LT1 when it was stock.

There was a guy who would redo powerdynes for porche 928's with better bearings, some cooling venting and some other stuff to boost their operating range to 60k rpm from 40k or something like that.

But for the cost of that it would be better to go the procharger or vortech route.

 

2cub49:
It's http://928motorsports.com/ ... they sell different head pulleys and an improved impeller also.
Where did you get the different crank pulleys from? I've been thinking of "fleshing out my midrange" a little. Is your 6# pulley for sale?

 

I bought my pulleys right from powerdyne.

http://www.powerdyne.com/beltsnpulleys.htm

It was the universal 2.7" for 9 lbs.
the 6 lb is 2.93" I believe.
Unfortunately we fubared the 6 lb pulley when we used a puller on it.
I'll see if I can find it from 6 years ago in my stuff and let you know if it's useable .

 

2cub49:
For some reason I thought the 6# setup used a 7" diameter crank pulley. I didn't realize all the boost differences were done with the head unit pulley. It's good to know what the head unit pulley diameter yields are. (my pulley set is 6" and 3") Thanks for the info. Wishing you good fortune with the new setup.

 

I had no problems running the 9# pulley.
I think it's 90.00 or so from Powerdyne.
If you're going to go to the trouble of changing out the pulley, which requires re and re ing the head unit I would recommend going with the 2.70 9# which will give you 5-6 # of boost.
You'll be disappointed with the 2.93 6 as I was when I ran it and only got 4# boost on stock 350.
Your current pulley is 3.12.
Also to tighten your belt better, tighten the bolts for the idler bracket almost tight then use a hammer and big screwdriver to strike the idler bracket.
It will move the belt tighter than you could otherwise get it, then final tighten the bolts so it doesn't get loose again.