KorbenDallas

I've been reading up on a couple of mods and I'm hoping you two might be able to help me out (or anyone else!). Please bear with me, I'm a newbie. The big plans for my Vette are a tranny swap to be done VERY soon (help!), then after some saving I'm upgrading my rims/tires, and finally I'm thinking about a supercharger (help!). So here we go:

GWHITE75: I need to know if Mike Fort contacted you about the details of your T56 install? I called him over the weekend asking him details about what I need to order to put a T56 in my Vette, and he didn't know too much about it. He said he was going to call you to get the details such as pictures, clearance issues, etc. I'm pretty much dead in the water until we can get some details! My mechanic said that he's ready to do it once he gets some more info also. I'm not trying to be pushy at all, I've been saving up for the tranny for a while and I'm excited. :) If you need some help putting up a webpage, I can try put up a very simple one for you if time permits.

Now onto the supercharger! I'm pushing about 450hp on the motor right now, but I would like my Vette to be a mid-high 11 second car at the least and would LOVE to be low 11s high 10s. I have some specs on my vette below. I've read some archived posts on the subject, and am I correct in saying that if I were to try for 650HP then I would have to do some major tweaking to my Vette? I really hope this isn't true. Would 550hp be more reasonable? I've also read that to be realistic, I should lower my engine's compression ratio to turn up the boost on the supercharger. My goal is to keep the stock small block hood with a supercharger setup that is reliable. I got some help from ylos today on superchargers, but which ones should I consider? Which ones should I stay away from? My budget for the supercharger itself is around $2500. These two sparked my interest, but I'm not sure if it would meet my clearance requirements and performance requirements?
Holley 144 Powercharger (is this thing a mini-blower?): http://www.jegs.com/cgi-bin/ncommerc...br=76&lastcat=
Paxton Novi 1000: http://www.jegs.com/cgi-bin/ncommerc...br=76&lastcat=
What about an ATI Procharger? I might be able to handle ~$3k for parts if the performance gains are that significant with an ATI. But I've read that a common problem with them is they throw belts once a week?

It looks to me like the holley is a small blower and the paxton is a centrifugal charger. I'm reading up on ATI Prochargers, they are boasting that they are intercooled so they can handle more boost. I'm not sure which would suit my needs better.. would a T56 stand up to 650hp?

I don't expect anyone to have read this whole thread or answer ALL my questions, but I appreciate any help that I can get! Thanks!

Here are my vette's specs:
I've got a 383 stroker at 10:1 compression, holley systemax package II (includes cam, heads, push rod package... specs & other info are here: http://www.holley.com/HiOctn/ProdLin...K/300-503.html), holley 750 double pumper, MSD 6AL/blaster coil (and I think their distributer also), stock AC, solid U-joints, and I have an extra fan on a manual switch just in case things get a little hot but I've only had to run it in the summer when it was ~95 degrees and high humidity. I'm sure there are some mods that I'm missing, but I can go through the receipts to find out if necessary.


[Modified by FroDaddy, 7:40 PM 1/23/2002]

Matt M

The Novi 1000 will support about 580 horsepower at max, so you would be better off with the Novi 2000. It will support over 1000 horsepower, so you won't need to upgrade it for a long time- just change pullies for more boost. Prochargers also make good power, but they seem to have some issues from time to time. You can run an intercooler with any brand of centrifugal supercharger. When I first bought my Novi2000, I was running a mild 355 (mid 13's car) and with 10 psi I hit 11.90's. This was at full weight and then some (3725 lbs total going down the track). I have since built a 388, and the car is a lot lighter and running an automatic. Without stressing the blower at all, the car runs mid 10's. If you live in or near Michigan, we could do a custom supercharger install in our shop.

Matt

KorbenDallas

Thanks for your help Matt M, and the offer to build up my vette with your experienced shop. Unfortunately, I'm not near Michigan or I would give you a call. Do you know of anyone good in north florida? :)

What have you done to lighten up your Vette? I'm wanting to start thinking about that now so I won't get tripped up during the touchdown run. Thanks again! :seeya

GWHITE75

FroDaddy,

I have yet to be contacted by Mike. What I can do for you is put something together and e-mail it to you. The website would be better, but I have not taken the time to set mine up. I have about 40 pictures of the transmission installation. I need to document it, which is where I am at now. I can tell you how I did mine, but the thing I can't tell you is how this transmission will hold up to drag racing duties. Norval has a Tremec 5 speed which he drag races and it might be a better fit for what your future plans hold in store. This transmission will fit my needs perfectly, but I don't plan on pushing it too hard (drag racing), although I will turbocharge my motor in the future. That being said, the main things you will need to do for this swap is the crossmember, driveshaft and console cover plate. The adapters in the front, along with the modified tailhousing case, place the output shaft back further than a GM style T-56, so you will need to make the appropriate adjustments in the tunnel and on the console. The shifter comes up right in the middle of the cover plate. Let me know if you are still interested in this swap and I can arrange to do the e-mails.

norvalwilhelm

You will have to lower your compression ratio for sure , down to 8-8.5.
Blowers. From the looks point of view nothing matches them . The carbs sticking through the hood, the whine of the belt, the front pulley spinning. They sure have low down pull. Maximum boost anywhere, anytime. Unreal torque. Go anywhere and people gather around.
Downside Adds alot of weight to the front end, visibility is impaired, can't run a intercooler, need double the expense of 2 carbs, limited to 10-12 lbs of boost. Least effecient of all the superchargers.

Superchargers Can run a intercooler and I feel the intercooler is important, can be hidden so no one knows you have it except for slight whine, can run alot higher boost, more efficent then a blower. Can be made to work with a carb but like injection better

Down side Don't produce that low end boost, At 3000rpm little boost, The boost is related to rpm so motor must be buzzed to create that rush, no image unless you show it off,

I like my 8-71 blower and will never go back to nitrous or a plain asperated motor again. I am spoiled. Even my wife's car is supercharged but GM went with the blower for her bonneville. It puts out 8 lbs anytime in a smooth flow of power.
Sure would like one on my 318 dodge 4x4 ram.

KorbenDallas

Thanks for your response GWHITE75. Yes, if you could send me the pictures I would love to get a better idea where I stand with the T56. Then once you document it, I would be able to put together a quick webpage for you. My e-mail is frodaddy@bellsouth.net

I'm not so sure the T56 would stand up to a lot of beating either. I'm pretty sure I can get 650hp out of the setup, and even now I run-and-gun a little bit on the road. What about these guys that have the same T56 and run low 11's high 10's on the strip? I watched tons of video's last night (http://www.racingfreaks.net/movies) where the guys are making 550-650HP with stock tranny's and are brutal on them. When I talked to Mike Forte, he said that he doesn't think the tranny would be a weak link at all and that if anything he would be worried about other parts instead, but then again I didn't tell him I would possibly be making 650hp down the road. Nothing is for sure, and what works for someone might not work for someone else. I just don't know if I could pass up the opportunity to have a T56 in my vette. The double overdrives is what has sold me. It would be nice if I could formulate some percentage of failure stories though!

More suggestions are welcome! If you could please send me the pictures GWHITE75, I'll get things ready once you get the documentation done. Thanks


[Modified by FroDaddy, 9:12 AM 1/24/2002]

KorbenDallas

Thank you for your help! I did ALOT of reading last night on the subject and have a better understanding of how it works. I definitely need to focus on a supercharger over a blower, and one that's capable of about 15lb of boost so it wouldn't strain it when I put boost on it. I've also found out that it's a debatable subject on how high of engine compression and how much boost you should run. There's always someone out there running 8.5 engine compression and 24lb of boost ( :eek: ), a more moderate 8.5 and 6-8lb of boost, and then "riding the edge" with a 10:1 and 10lb of boost. It's all subjective.

Since my goal is 650hp, I would need to run somewhere around 10lb of boost. Matt M has a similar setup as mine would be. I would keep my 750 double pumper and probably get a Paxton novi 2000 or ATI procharger. Based on my research so far, I'm leaning toward a novi 2000.

Still, I have unanswered questions that I will have to get answered before I move foward on this: What parts would I need to upgrade to make my engine "supercharger ready"? Will a T56 tranny rated at 400hp hold up to a 650tq monster? What other parts could possibly be a weak link?

Thanks for your help norvalwilhelm, I really appreciate it!

norvalwilhelm

Susperchargers also like cams with 112 lobe centers. You can get away with 110 but the 112 or 114 is better. Your carb needs to be modified for the boost. In a chart I have in front of me it shows up to 9.5 compression and with 10 lbs of boost the effective compression is 16.0. With 8 to one and 10 lbs of boost the effective compression is 12.4. With supercharged engines they always say lower the compression and up the boost. You will be running around alot without any boost whatever so maybe you would like a little extra compression.

KorbenDallas

I've heard from several people that I would need to lower the compression on my engine and up the boost on the supercharger, so I'm sure this is something that is learned by experience. Deviation from this might blow things up. However the higher effective compression is, the more horses you get. My goal is 650hp, so I will have to have a high effective compression to get to that goal.

What are the advantages of running higher engine compression and lower boost? Lower engine compression and higher boost? The end result is the same, so wouldn't it be better to have higher engine compression and lower boost? Is 650hp for my 383 realistically reliable? Or should I set my goal a little lower?
What modifications would have to be done to my carb to make it compatable?

Thanks again norval. Answer questions and get more in return! :blueangel:

GWHITE75

You have e-mail. Let me know if you got all of them.

I just received notice that your box was full, so I need to resend, but I think my first mail might have overloaded your box. Is there a better way to get these to you?

I think you might have gotten the first 7 photos. E-mail me at gwhite@foxboro.com


[Modified by GWHITE75, 10:20 AM 1/24/2002]


[Modified by GWHITE75, 10:22 AM 1/24/2002]

norvalwilhelm

If you took a say X volumn of gas mix and compressed it to say 12.1, then take another motor with alot less compression therefore more space to fill in with mixture then compress to get the same 12.1 the second motor would have more mixture to burn thus more power. Supercharged engines do not run alot of compression. I have an article where a guy started with 10 to one and run alot of boost and he seems to be getting away with it.
You car need an extra block like a metering block. You sandwich these two blocks together with longer screws between the carb body and float bowl. These two added blocks have a line running between them. This equalizes the pressure in the float bowls. You also need and elbow that fits in place of the air cleaner where the boost hose is attached.

KorbenDallas

I got 14 of them, and yes my bellsouth mailbox exceeded its limit. I apologize for that! I've sent you two e-mails, one from my personal acct and the other from my work acct. You can send the pictures to my work e-mail. I shouldn't have any limits, and if I do I can change that. :jester

KorbenDallas

I stand corrected. So you're saying that I could lower my engine compression, have the same amount of boost, and have more HP? What would happen if I lowered my engine compression to lets say 8.5, added enough boost to have the same effective compression as 10:1 and 10lb boost (~18 effect comp)? I would have more power? Maybe even over my 650hp goal?

Perhaps there is a website that I could read up on effective compression and supercharging a little more. That would probably kill all of these newbie questions :)

norvalwilhelm

They don't advise more then 12 to one effective compression on 92 octane. When you lower the compression you up the boost. I personally run almost 15 to 1 with 8 to 1 and 12 lbs of boost. I also o ringed the block and use copper gaskets and studs.. With the blower I get boost everywhere, pass a car, accelerating from a stop sign etc. With a supercharger you will not get this boost, you will have to rev the motor. If you push it at 1500 rpm how much boost will you have? None. Below 3000 your motor will not have boost so a little compression might help. If you like revving the motor the supercharger will work better for you then a blower. I am sick of the high revs and like to down low grunt of my 8-71. I have a bigblock that only worked from 5000-7500 and it comes tiring on the street with the high stall convertor and seeing 5000plus anytime I put my foot in it at all. A supercharger would have loved it.
I have alot invested in my motor and hope it has a long life.

Matt M

Norval has it exactly right. If you lower the compression (bigger combustion area), then raise boost to end up with the same effective compression, then you will have more horsepower. This is because the combustion area is larger- similar to just running a bigger engine.

You also have to realize that since centrifugals make their boost exponentially compared to RPMs, then max boost can be higher. In other words, with a positive displacement blower(6-71, B&M, etc...), boost is the same at all rpms, as long as you have the throttle open. They also heat the air more than centrifugals. These two factors make it important to use a lower compression ratio, such as 8.5 to 1. With a centrifugal supercharger, if peak boost is 12 psi at 6000 rpm's, then boost will only be around 3 psi at 3000 rpm's. Since detonation is most likely to occur in the midrange where peak torque occurs, the boost curve of the centrifugal is much safer then that of the positive displacement blower. This allows higher compression ratios to be used safely. I have successfully run 8 psi with 10 to 1 compression and no intercooler- on 93 octane. You wouldn't want to do this with a positive displacement blower. The roots (positive displacement) blower will make a LOT more low end power, but I doubt that you would be able to use it on an already high-torque stroker.

Matt

KorbenDallas

Thanks norval, gwhite, and matt m for helping me out. I was going to post again with more questions, but after reading and thinking about the responses I've got all the information I need to make a better decision.

Yes, I want a centrifugal SC such as the novi 2000 and want 650hp after everything is done. Whatever combination of compression ratios to make it work safely is fine with me. I'm open minded to doing some any type of work; cam or whatever, that is necessary to get there, if a SC couldn't do the job to 650hp safely with my setup.

What's going make my final decision is how much $ I'm going to have to spend to get there. I'm not mechanically inclined enough to even fathom how the details would work to get the SC on my vette, so I will be paying someone to do the work for me. I created this post so the great guys/gals on the forum could help me out so I will have a better idea of the do's and don'ts of supercharging.

In the end, it looks like it will be possible to attain my goal of 650hp with a supercharger. You can go as fast as you want to if you have the cash, but I don't have the cash flow that would allow for anything more than just one more major mod. Even with the costs of a SC, I'll be cutting it close with my finances! (Maybe it's time to sell the girlfriend and relatives... EBay here I come! :crazy: :lol: )

Thanks for the help guys! I'll definitely be looking into a centrifugal SC if everything goes well. Keep your eyes peeled on EBay! :jester

norvalwilhelm

(Maybe it's time to sell the girlfriend and relatives... EBay here I come! )

Could you please send pictures. :D