scarp Posted July 11, 2000 Share Posted July 11, 2000 HELP I JUST PUT TOGETHER A 302 CHEVY and I need to get some advice.. this motor is a low compression 302ci that needs super/turbo charging HELP NEEDED (what do ya'll recommend?) Stan Quote Link to comment Share on other sites More sharing options...
Z-Dreamer Posted July 11, 2000 Share Posted July 11, 2000 Scarp, Sounds like it's time for an ATI ProCharger! John Scott and BLKMGK are the two you need to talk too! Man you're fast, that new ride is already running? You'll be even faster with the blower. Mark P.S. Check out the Variable Roller Rocker post in this area and leave a comment. Thanks ------------------ [This message has been edited by Z-Dreamer (edited July 10, 2000).] Quote Link to comment Share on other sites More sharing options...
scarp Posted July 11, 2000 Author Share Posted July 11, 2000 Check the (I'm Telling ya...) post's for more info. Stan Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted July 11, 2000 Share Posted July 11, 2000 Go blower. Twin turbos make more ultimate power but would need to be custom fabbed and cost at least as much as a blower. I sthis EFI or carbed? ATI makes kits for th eSBC including carb'ed kits. I don't know how well they package under the Z hood but another member has done it so he'll be best qualified to ask. Personally I prefer intercooled boost but it's more money and you've got packaging issues to deal with. I've been quoted about $1750 for an ATI SBC carb kit sans intercooler and I can hook you up with the folks that gave me that quote if you would like. 'Course there is one other option if you don't need the power all the time - NOS. Have you considered this? Quote Link to comment Share on other sites More sharing options...
SpeedRacer Posted July 11, 2000 Share Posted July 11, 2000 Wow, I'm jealous!! 302 mouse motors are awesome and love to rev so I would go with a turbo setup. I'd do a small one or twins so you don't get to much turbo lag. Install a boost control knob on the dash and have fun!!!!!! Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted July 11, 2000 Share Posted July 11, 2000 I honestly believe that a blower is a far easier task than trying to do a turbo or worse two turbos but power-wise it would be much faster! So... http://www.rewarderheaders.com/turbo.htm spotted that while researching headers for my car through a link someone else here gave me. They do custom setups too it seems... Quote Link to comment Share on other sites More sharing options...
John Scott Posted July 11, 2000 Share Posted July 11, 2000 Stan I vote for the instant gratification factor. ATI PROCHARGER!! Make sure you get a boost regulated fuel regulator. I use the Mallory with their 140 pump. Set the idel psi to about 4-5. Also I can fill you in on modifying the carb. Simple to do. 12 rib if you get greedy for more power and later bigger badder projects. Whats your compression? Man this thing will fly!! JS Quote Link to comment Share on other sites More sharing options...
Guest Fast Frog Posted July 12, 2000 Share Posted July 12, 2000 Scarp: I looked at twin turboing my 383 5 yrs ago. I did a card board mock up using the dimensions of two S-4 trim/.63AR each hung on special fabricated header/turbo mounts for each bank with 2.5" down pipes. Separate intakes to each compressor which collectively dumped into a 3 bank Cartech intercooler and then into a specially built intake plenum into twin 58mm LT-1 throttle bodies. This setup was for 10 to 12lbs of boost for 550-600HP. It would have been awesome if it would of FIT!!! There just wasn't enough space in a Z 40"X40" engine compartment without some serious modification of the fire wall, whl wells, front end, and hood. Now, to some who are mechanically/machine shop experienced, this may have not been a big problem. But to me it was. So I opted to go supercharger. At that time, Paxton was the only one that had a small enough configuration to get everything under the hood. I still had to do a fair amount of fabrication and machine shop work to accomplish this. Now, ATI has perfected the centrifical type supercharger. And is small enough to place into a Z engine compartment without to much fabrication (See Eric Berstein's ATI supercharged 350 Chevy in a 240Z in Dec, 1999 Turbo and Hi Tech mag). Outfits like Turbonetics and Turbo City may have advanced turbocharging enough to have a single turbo setup for a 350 and larger V8. I know that there was a single turbo setup for a Ford 5.0 a few years back, but it was a "tricky" setup with cross over pipes and such. My humble recommendation would be to check into the possibilities of a good single turbo set up for your 302 V8. You won't have belts and special pullies and you can set the sys up with a boost controller to whatever application you want-street, drag race, etc. You can't change the boost on a supercharger with out changing pullies or SC gears. If that's a no go, collaberate with John Scott et. al. who are currently using ATI Prochargers. You might give Top End Performance a call (818-764-6768) and ask about Eric Berstein's car. Good luck, AND BY ALL MEANS KEEP US POSTED!!! (I'm thinking about going ATI myself) Quote Link to comment Share on other sites More sharing options...
scarp Posted July 13, 2000 Author Share Posted July 13, 2000 I have found a set of twin turbos off of a 300zx in great shape. I know I am in for Plumbing headaches ect. would these work on a 302ci v8 ???? Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted July 13, 2000 Share Posted July 13, 2000 Well, they were specced for a 3liter, right? You're not quite double that at about 5liters. However, people have gotten a good bit of power from the stock turbos and you could always have them "wheeled" later on if you chose. Will they fit? Ponder this - instead of finding turbos at a cheap price and making them fit, consider finding turbos that will fit most easily and flow what you need. Then consider the cost. In the long run it may prove cheaper to do it this way rather than dealing with a "cheap" part that only "sort of" fits. Am I making sense? If these turbos look promising from a fitment standpoint figure out the HP target you've got (forget lbs of boost for a moment). Then call a reputable turbo shop and see if they will flow what you want. I think they'd work as I think they're slightly bigger than the T25s I ran on my 302 which made 450hp. I ASSume you want more than 450hp tho'. Quote Link to comment Share on other sites More sharing options...
scarp Posted July 14, 2000 Author Share Posted July 14, 2000 Maybe I'm looking at things wrong but it seems that the more exhaust flow 3 liters vs 5 liters to the turbos they would spin even harder creating more flow than the 3 liter. and I was thinking small turbos = faster spin up and less turbo lag. but I guess I'm pretty DUMB on this. This is why I need help with this fantasy... Stan [This message has been edited by scarp (edited July 13, 2000).] Quote Link to comment Share on other sites More sharing options...
Guest Fast Frog Posted July 14, 2000 Share Posted July 14, 2000 Scarp: FYI, a real good book on the ins and outs of turbocharging is one written by Hugh McInnis titled "Turbocharging". Over the last 20+ yrs this has been the "bible" giving a great overview of basic application and "how to". It's got enough math to keep you interested and lots and lots of examples. Quote Link to comment Share on other sites More sharing options...
Drax240z Posted July 14, 2000 Share Posted July 14, 2000 I'd like to recommend a different book. I haven't read the one Fast Frog lists. But I bought "Maximum Boost" by Corky Bell and it blew me away. Its by far the best systems engineering book that I have ever laid my hands on. (It deals specifically with turbo systems) Its a bit pricy, but I consider it one of my best investments yet on my turbo project. ------------------ Drax240z 1973 240z - L28TURBO transplant on the way! http://members.xoom.com/r_lewis/datsun.html [This message has been edited by Drax240z (edited July 14, 2000).] Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted July 14, 2000 Share Posted July 14, 2000 Turbo sizing is important for a couple of reasons. First, the exhaust housing must allow enough gas to get by without choking the engine. If this happens not only won't the engine run well but the heat build up will simply amaze you Second, as you might have read elsewhere here boost is a measure of restriction. On a centrifigul blower removing restriction from the heads and intake can result in lower "boost" numbers yet the blower still turns the same RPM and still pumps the same CFM - the engine is simply ingesting it easier. The same thing will happen on a an engine who's cubes have been increased. All things being equal it can consume more air and make more power. when you have a turbo that's sized for a smaller engine and run it on a larger engine it's wastegate will attempt to keep the turbo running at whatever boost it was set for. Because the engine is capable of consuming more air the turbo will have to spin FASTER to make that same boost pressure. Turbos, like blowers, have a "sweet spot" or range of RPM where they're most effecient. Stepping out of this range leads to "interesting" things happening. For instance you may see higher boost numbers but no added power - the added heat in the air has reduced the oxygen. Or the impeller may even self destruct as the forces of spinning so fast (exponential forces I believe) pull it apart! This is why blowers and turbos have what are called "compressor maps" that document where the device is most effecient so far as pressures and impeller RPM. Sized correctly a turbo will NOT have lag unless you've got it sized to run insane boost pressures up high. Twin turbos allow you to use two smaller turbos to get fast response and great volumes of CFM - they need not be huge. One thing you DO have to watch with smaller turbos is boost creep - this occurs when the wastegate cannot bypass enough exhaust to prevent the impeeler from spinning fast enough to broach the max pressure setting you've made. Porting the housing and other things can help prevent this - chances are you won't have this problem but it's worth mentioning. Whew - hope that helps! Seriously, get a book and read up on this stuff. If you're seriously considering trying to build this you'll want as much knowledge as you can get! I've read one of the books posted above, don't think it was Corky's but I'd liek to get my hands on that one! Read up on NOS and "superchargers" too. Lot's to learn there and the books are CHEAP compared to learning the hard way. My Mustang's turbo system was researched for a looong time before I did it and I still got bitten by a few "things" (grr). It was a kit but you'd be amazed at what doesn't get documented very well. That's why this Z I'm building will be carbed first - KISS and then get comlicated Quote Link to comment Share on other sites More sharing options...
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