lesd Posted December 16, 2006 Share Posted December 16, 2006 So I've been slowly getting things for my engine build to replace the 327 that is in my 240Z at the moment. The goal is a redline of 5500 , auto trans. , street driven car ( weekends, not daily ). I haven't decided if it will be single or dual turbos. I am leaning towards the twins, TO3s with integral gates. I will be welding my own plumbing, TIG'ed stainless and aluminum. I have a T72 if I go single. Boost target will be about 12 - 14 lbs. W large intercooler. Transmission will be a 4 speed auto, built 2004r or similar OD tranny. My LT1 is out of an F-body, 1996. AL heads. So here is my bits n pieces that I've picked up so far: Pistons: Speed pro turbo,forged, 844-L2441F, about 8.7:1 at 58cc's Eagle H beam rods. Wolf 3d EMS ( I will tune with wide band ) Ford 38lb injectors ( I think I'll need 42 lb injectors , however ) Stock crank. ( heard it's pretty strong from the f body forums) What I still need: ARP stud kit for heads and bearings. Gasket set, Should I worry about O ringing the heads? Valve springs , rockers, etc .... what should I do here , keeping in mind that the motor will be relatively low revving. CAM !!! ( I'm lost here. trans stall will be mid range since the car is light. ) Bearings ( should I let the machine shop get these for me ? ) Rings Oil pump Cam chain kit My main mystery is what to do with the heads and cam. I want to keep the stock AL heads. Keeping the rpms to 5500 should help save money here as well. Any advise most appreciated! -Les Quote Link to comment Share on other sites More sharing options...
lesd Posted December 17, 2006 Author Share Posted December 17, 2006 Did the fuel injection stump everyone ? A couple of simple questions to add : Can non-LT1 cams be used in an LT1 ? What boost are the other chevy hybrids running ? Since my heads are 53cc , can I get the compression down a bit by machining out the combustion chambers in the heads a little ? I want to keep the CR to 8.5 . Quote Link to comment Share on other sites More sharing options...
DavyZ Posted December 17, 2006 Share Posted December 17, 2006 Search for posts by Siliconeboy and Turbomeister. Both have turbocharged Chevy V8's. There has been a number of good threads regarding this topic. Davy Quote Link to comment Share on other sites More sharing options...
silicone boy Posted December 18, 2006 Share Posted December 18, 2006 Great project. The good news is you can make some real strong, durable and efficient headers by getting the LT1 Corvette headers, cutting the flange and welding on a T3 flange, and flip them over. There is just enough room under the Z hood for the turbos if they sit at the midpoint of the engine just behind the shock towers. Other configurations are also possible, and you will probably have to use external wastegates. Quote Link to comment Share on other sites More sharing options...
Turbo Meister Posted December 18, 2006 Share Posted December 18, 2006 Did the fuel injection stump everyone ? A couple of simple questions to add : Can non-LT1 cams be used in an LT1 ? What boost are the other chevy hybrids running ? Since my heads are 53cc , can I get the compression down a bit by machining out the combustion chambers in the heads a little ? I want to keep the CR to 8.5 . I'm running 17 psi boost without wastegates or intercooler. I don't have problems so long as the engine receives enough fuel, under boost, and if I don't get too greedy with the ignition timing. Don't worry about O-ringing if you just buy Cometic or Fel Pro Multi Layer Steel head gaskets. Your 8.7 cr is fine unless you want 35 psi boost. Just be aware that proper A/F ratio and correct ignition timing is crucial to a turbo engine. Hanns Quote Link to comment Share on other sites More sharing options...
lesd Posted December 18, 2006 Author Share Posted December 18, 2006 Meister: No wastegate ! holy smokes, that must be interesting! So does the torque curve behave like a procharger, with not much on the low rpms, and then a big kick ? I had a VW bug a long time ago, and it had the same setup. It loved to detonate, until I put an old carter knock control on it, that box worked pretty well. How much compression are you running ? Silicon: Why do you say external wastegates? Fitments issues? Did you tune the engine, and do you have any recommendations on timing during boost? What's your CR and boost at the moment ? Still wondering about the cam. Maybe I'll just get a so called turbo cam from compu, or an RV cam from Crane. The reason I asked about SBC cams in an LT1 is that they are a lot more plentifully. ( and cheaper too ... summit sells their own branded ones that are made by Crane also ) I'm making my final shopping list for Santa this week Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted December 18, 2006 Share Posted December 18, 2006 What did you guys do for the turbo oil feed and drain? Would what you did for the old school SBC apply to an LT1? 1 Quote Link to comment Share on other sites More sharing options...
wheelman Posted December 19, 2006 Share Posted December 19, 2006 lesd, It might be possible to run a cam for a later model SBC that is a roller but you'll need to modify it to drive the opti-spark. Not sure about specifics on this but the 96 opti will use the shorter of the 2 dowel pin lengths the LT1 had and will require a hole about 1" long and .5" diameter drilled into the front of the cam for the opti shaft to slide into. You'd might need to run an electric water pump as well because the LT1 cam gear may not bolt to an earlier cam and the water pump is driven off the cam gear. By the time you do all that it would probably be as expensive as buying an LT1 cam to start with. Have you thought much about what you'll do with the PCM to provide more fuel based on boost? A rising rate fuel pressure regulator might work but it's not as accurate as adjusting the programming in the PCM if it's possible. As for the CR, it should be possible to have the combustion chambers opened up to get it down or even use the iron LT1 heads which have 63CC chambers (I think, might be 58CC). Anyway lots of options here. Wheelman Quote Link to comment Share on other sites More sharing options...
lesd Posted December 19, 2006 Author Share Posted December 19, 2006 Wheelman, for the ECM I decided to go with an aftermarket one, the Wolf 3d. I got it for a good second hand price, and it offers a lot of features. It is speed density, so the fuel map can be tuned to whatever you want as far as fuel enrichment goes. Since I don't have a base map, I guess I'll just be careful and tune it with the wideband O2 meter. The O2 I have does data logging, so I can use that to help tune. Some systems, like the FAST ecm have a direct way to tune the fuel maps based on a target F/A number, and holding the load constant and hitting a key for 'zapping' the mixture to the desired value. If anyone can give me a good basic ignition map for a boosted Chevy V8, that would help me get started when it comes time. I'm a bit more concerned about running too much timing, since the O2 does not help much in that department. I was going to use LT1 edit, I even purchased it a while ago , but my GM ECM is MAF based, and that would be undesirable for a turbo engine. Thanks for the cam info, you are right, I may as well just get an LT1 cam. Les lesd,It might be possible to run a cam for a later model SBC that is a roller but you'll need to modify it to drive the opti-spark. Not sure about specifics on this but the 96 opti will use the shorter of the 2 dowel pin lengths the LT1 had and will require a hole about 1" long and .5" diameter drilled into the front of the cam for the opti shaft to slide into. You'd might need to run an electric water pump as well because the LT1 cam gear may not bolt to an earlier cam and the water pump is driven off the cam gear. By the time you do all that it would probably be as expensive as buying an LT1 cam to start with. Have you thought much about what you'll do with the PCM to provide more fuel based on boost? A rising rate fuel pressure regulator might work but it's not as accurate as adjusting the programming in the PCM if it's possible. As for the CR, it should be possible to have the combustion chambers opened up to get it down or even use the iron LT1 heads which have 63CC chambers (I think, might be 58CC). Anyway lots of options here. Wheelman Quote Link to comment Share on other sites More sharing options...
lesd Posted December 19, 2006 Author Share Posted December 19, 2006 I have done a bunch of searches, but alas , I think that some members are holding their cards *real* close to their chests when it comes to specific details on the engine bits that they used :cool:. Perhaps I missed a thread ? -Les Search for posts by Siliconeboy and Turbomeister. Both have turbocharged Chevy V8's. There has been a number of good threads regarding this topic. Davy Quote Link to comment Share on other sites More sharing options...
Turbo Meister Posted December 19, 2006 Share Posted December 19, 2006 Meister: No wastegate ! holy smokes, that must be interesting! How much compression are you running ? Most of the turbo power comes on in the mid range for my Z unless I launch with more than 10 psi of boost. Then if it hooks, the front wheels lift at launch and if it doesn't the rear tires spin. CR is 8.5. I can't help you as much as I would like because I have an old school SBC with carb. No one on this site would hold back info from you because we all want you to succeed with your project. If you look at Siliconeboy and my previous threads there is much info but maybe not as much as you want from my set up. For a street application the stock LT 1 cam should be sufficient on a turbo application. Hanns Quote Link to comment Share on other sites More sharing options...
Turbo Meister Posted December 19, 2006 Share Posted December 19, 2006 What did you guys do for the turbo oil feed and drain? Would what you did for the old school SBC apply to an LT1? Scottie, My turbo oil feed comes off the existing oil pressure port for the OP gauge. My oil drains enter near the front upper portion of the oil pan. Seems the LT 1 would use a similar set up. Hanns Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted December 19, 2006 Share Posted December 19, 2006 Scottie,My turbo oil feed comes off the existing oil pressure port for the OP gauge. My oil drains enter near the front upper portion of the oil pan. Seems the LT 1 would use a similar set up. Hanns Thank You! Quote Link to comment Share on other sites More sharing options...
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