I have noticed that the Vortech and Powerdyne blowers for LT1's normally only provide around 6lbs boost. Now is this becuase a stock LT1 shouldn't take more than that, or is the blower just limited? Because I am more of a turbo guy, and see them running anywhere from 4-20psi on engines. I am trying to get my turbo setup done on my 81 small block chevy, looking at around 10-14psi. But why so low on all these blower kits I see for LT1's? What kinda power gain will you see at the rear wheels with a measely 4lbs??? Please enlighten me

BamaZ28

 

I think the fact that LT1 stock pistons are crap is a big chunk of it

 

Well, the only safe way to run these cars with boost on the stock bottom end is to run 4-7 psi. Anything over that and you start running the risk of breaking things. Alot of people here are running big boost on there supercharged vehicles. You got people on here running anywhere from 7-18psi of superchargered boost. Look around some more and you'll find some high boosted cars.

 

The low boost is due to the stock pistons, and the motors high Compression. Once the compression is lowered and better pistons are installed, with the fuel system and computer redone high boost numbers can be done. It is just a matter of money and such.

 

The Vortech S-trim will provide up to ~14-15psi on a 350-383 depending on how well it breathes. A Procharger D1 a bit more. As you figured, they are not spun very high on a stock bottom end for fear of piston damage. Many are running larger blowers, which will provide more boost. My current setup uses a Procharger F1, and I am seeing ~18psi and it could be spun up to 20% faster, so it's far from maxed out.

Rich Krause

 

Well...sorry we all can't run 20# of boost. "Measely 4 lbs" 4# is better than no boost. Me for example I only see about 4.5#. Why?? I am saving to have the motor rebuilt. Sure 4# will only give you so much, but it's still a very nice increase in HP. Like everyone has said with 10.5:1 hyperpeutic (hyperpathetic) pistons you can't throw but so much boost at em. Sorry to rant, just kinda sick of hearing people talking like if you are not gonna throw 20 #'s of boost at a car you shouldn't throw any at it.

 

Im trying to run 12psi...........but I dont like to turn the rpm with this damn missfire!....

 

Along with the aforementioned hyperuetic (sp?) and high stock compression, it also has to do with the fact that those kits probably aren't intercooled. ATI sells 8 or 9 PSI kits for stock cars because of their intercooling. I'm not sure about the Vortech kits with aftercoolers.

 

Sorry, you got it all wrong. I wasn't bashing those running lower boost levels. Just when you compare 20+# to 4# it is kinda "measely", that's just a descriptive term!! I got props for anyone running boost!!! I am curious about how much power increase did you get out of a stock LT1 running at 4# boost? Thanks

BamaZ28

 

It's cool. I think I was just pissed about something when I posted. I'll admit 4# isn't a lot at all. I just went with the blower vs heads and cam idea due to the fact the blower with install was actually quite a bit cheaper. As I bought the blower, fuel pump, and ignition used. I got lucky and everything was in good shape. I will rebuild this winter hopefully and turn the boost way up on the ol S-Trim. From what I've been told you see AROUND 15 HP per # of boost on a stock LT1. Therefore in my case seeing 4.5 # I may have a increase of around 70hp. That could very a tad, but I believe that's about ballpark.

Stephen

 

So could I run 6# safe with some sort of after/intercooler setup...I AM going to get a blower for my LT1, I wanna get as much info as I can before spending the money...what is the best setup, I would prefer to buy used.......with some kind of cooler, please make suggestions

BamaZ28

 

I had really good results with my P600b setup from ATI. You can look at my older posts to see the longevity I have had on a stock motor. Good luck, but my two bits of advice:
1. Get the S/C setup dyno tuned as soon as the blower is installed( include the dyno tune/computer recalibration as a cost factor of going supercharged)
2. Save up to eventually do a rebuild. It does not have to be a $5-$10,000 rebuild, (I did mine for just around $1,800) but it will come someday.
Hope this helps.

 

So, how much should I pay for a s/c "capable" of pushing 15#? What price is good for the air cooler? I don't wanna run the high boost until I build the engine to handle it, I wanna push about 5-6# on the street until I get the engine built for more boost. So, also, how much for a good dyno tune and computer reprog? And how much boost will the stock injectors take? Thanks for your answers and patience.

BamaZ28

 

I actually feel I got a steal on my used S-Trim. I got it for 1475 shipped. It was missing a few misc. parts but that was expected. I am not too familiar with the ATI blowers. As far as Vortech goes you could always get the T-Trim with a vortech aftercooler. I went with Vortech due to the fact I have one friend who has had 3 Vortechs all on different cars and has never had any problems. Another buddy of mine off this site has had 2 or 3 Vortechs with no problems. So I based my decision on that and the fact I found the Vortech kit so cheap . I have heard some people say ATI makes a LITTLE more power, but nothing an extra pound on the T-Trim couldn't solve. With the aftercooler and a tune if you have the money (I didn't) you would be fine on 5-6 #'s for a while. No guarantee. I feel A LOT has to do with how you drive it. With the FMU stock injectors can give you enough fuel for 5-6 #'s. I have heard nothing but negative things on the FMU's though. I run one myself. One major downfall is the fact they give the car so much fuel. You run a little rich. I don't mind that as rich = safe...but also equals loss of power. I'm willing to sacrifice that power for safety right now. The other thing I have heard about them that bothers me a little is the fact they can run inconsistent. That is very very bad thing! If at some point you are gonna go bigger injectors. I would say maybe just rely on the FMU for a while. No problems with mine. Then when you rebuild and crank up the boost you can look at those bigger injectors. I am obviously not the best to answer your questions...but I will certainly be glad to tell you what I do know. Feel free to ask away...if I don't know I will tell you I don't. I'm not the type that's gonna feed you BS just b/c I don't wanna not give you an answer. So if you have any questions I'll do my best

 

I have run my stock injectors since day one, but if I ran anything above the boost that I am running now I would go to a bigger injector. I would consider myself on the low side of boost (7-10psi). Others may say this or that but I feel that the stock injectors are fine at the low boost as long as you have the tune correct. The biggest failure of the fuel systems seem to be the FMU's. They really don't give any type of warning that they are going bad. I just said screw it and got rid of mine after it went bad. As for the dyno tune cost I really can't say exactly, (I was told around $250-300) I was very lucky that I knew a friend that knew a guy who owned a dyno, so the cost for me was a whopping $20 bucks, some fast food, and three+ hours. For the computer I am also a very small minority, in the fact that I am running a Hypertech custom supercharger program. Other people have said negitive things about it, but for me the program has been on the car for many years. And I am quite sure that the reason I cracked #1&#7 ringland was due to the FMU going south not the computer programing. But like I stated earlier I am running a "low Boost" setup so those are my results. Also their are guy's on this board that provide some great info while others talk from hear say. You can easily see the ones that know their stuff. Keep asking specific questions and it may take time but people will help. One last thing I would also interject about Vortech, is that I have seen what they put out on their first systems for the LT1 and can say they did not really setup the customers for success, the systems now are great, but the earlier systems that were running 9+ psi without a intercooler were bad news. I seen two cars that put those sytems on back in 1995, and the motors gernaded fast. Now with the increased knowledge of the high compression LT1 and its weak points supercharging a LT1 is a little easier. Sorry for the long post but I hope it helps. Good luck.