denny411 Posted January 10, 2003 Share Posted January 10, 2003 I`m considering a sbc twin turbo with efi for one of my Z`s. 1)Would it be better to run aluminum or cast iron heads? or would it depend on How much boost I run? 2)What would be a good efi system to use? 3)approximately how much boost would be needed to achieve 750 rwhp? 4)What size turbo`s would I need for this setup? 5)How much compression without boost should I run? ScottyGNZ`s reply to the "who has the fastest Z" question has got me thinking, that even under relatively low boost, a ttsbc should really put out some serious power Quote Link to comment Share on other sites More sharing options...
yo2001 Posted January 10, 2003 Share Posted January 10, 2003 Sounds like something you would do. 1)Alumnium heads would be a better choice since it can lose heat faster than cast iron heads. Less detonation. 2)Sanny's blue 240Z ran TecII, Hesco dyno tuned it. 3)You well need more than 14 spi for sure 4)7:5 to 1 compression and alot of boost. I would like to see you stick a LS1 with TT. LS1 comes with pretty flexiable ECU. Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted January 10, 2003 Share Posted January 10, 2003 Scottie is right! For that HP level, I would start with a Dart block, high end forged steel crank(not imported), same goes for the rods. The pistons will need to be of high quality(JE probably has them on the shelf). The heads would be aluminum, get the big combustion chambers(most companies have differant combustion chamber volumes to choose from). Edelbrock heads have very thick deck surfaces. Some Victor Jr. heads should do the trick. I would go for twin T4's.(I have been told to use a pair of T3/T4 hybrids by some import builders, but I think the turbines would become a restriction) They should be matched, so that means getting them both from the same place, at the same time. I would PERSONALLY use a TPIS Miniram(Grumpyvette is sold on the Holley Stealthram, but it is too tall IMO, and requires a big cowl hood). Obviously, a stand alone EFI would be required. Maybe F.A.S.T or Holley Commander 950. Quote Link to comment Share on other sites More sharing options...
Guest eric-z Posted January 10, 2003 Share Posted January 10, 2003 I thought I read somewhere that cast iron heads were better. I think it is because it retains heat and keeps the temperature in the exhaust gases which helps to spool up the turbo quicker. eric by the way I could be totally wrong on this.... I just thought I remembered reading it somewhere Quote Link to comment Share on other sites More sharing options...
fl327 Posted January 10, 2003 Share Posted January 10, 2003 dual t04bs would be nice, i think a t3 based turbo on a v8 would spool way too quickly to be of any use. Quote Link to comment Share on other sites More sharing options...
denny411 Posted January 10, 2003 Author Share Posted January 10, 2003 How much boost would twin t4`s build on a 350? I have a 3.5" cowl hood already. would that be tall enough? The block I have is a GM performance ZZ3 block, It came from GM with 4 bolt mains and a nitrided steel crank. Any ideas on power potential or how much it could handle? Obviously I would need better rods/pistons and have it balanced, but the block is std, with no measurable wear, so cyl wall thickness shouldn`t be a problem. I`ve also got a line on a pair of dart pro1`s with 200cc runners. I believe they have 76cc chambers. Any thoughts or experiences with deck thickness on those? Quote Link to comment Share on other sites More sharing options...
fl327 Posted January 10, 2003 Share Posted January 10, 2003 dual t04bs would make HELLA boost, im not sure if even those would be too small maybe go twin T04es 500hp walk in the park-or a walk in the dark if you havent worked with turbos before. its not easy, but it sure is fun-like crippin and pimpin. Quote Link to comment Share on other sites More sharing options...
Guest empracing Posted January 10, 2003 Share Posted January 10, 2003 2 words nuclear @#$%ing weapons!!! try www.twinturbov8.com.au 750 hp at the wheels from 14psi 355 or 383 holden is real ez so i cant emagin a chev being a problem Quote Link to comment Share on other sites More sharing options...
denny411 Posted January 10, 2003 Author Share Posted January 10, 2003 Thanks for the input. I am planning to build an na 383 hybrid with around 450 hp to get me by for awhile. The more I think about it, I start to realize. If I truely want to have a low 9 sec street car, Turbo is pretty much the best route. I like the idea of being able to drive hundreds of miles with relatively good mpg, and still be able to to pretty much smoke most of the track only cars out there. I know this will be a long process, and IF I decide to go this route, I`m pretty sure that the 450hp car I`m building now will keep me satisfied.(FOR AWHILE) Quote Link to comment Share on other sites More sharing options...
Guest Luigi Posted January 10, 2003 Share Posted January 10, 2003 Hey Denny, good to see (?) you again. I had fun in Ala. Oz Cheek at KB pistons has a twin turbo 350 that did 591 rwhp on mallorys dyno. It's a stock block dart eagle heads w/mild porting. eagle h-beam rods stock crank (I think) Vic jr. w/bungs Accel elbow w/some TPI throttle body. DFI 6.0. He welded/hacked and slayed a set of cast iron manifolds to mount the turbos. IT's what we call a junkyard engine ( the last one we called dog food and it made 400+ with a BLOW through carb set-up). I guess my point is this: fuel management, exhaust (it made 491 rwhp before he dropped the exhaust and it's 3" all the way back...both sides) BIG no HUGE intercooler, fuel managment. I know I'm gonna get blasted for this but here it is, the manifolding to the turbos is not what I would fret about. we tried a set of sandersons turned upside down...the turbos were out the hood...we bailed on that idea. The 350 stuff is so cheap that to me it doesn't make since to screw with weird combos on a turbo. Plus you're gonna hurt somthing if you lean on it (and you will) so make it cheap) to this end I would use alum. heads. If they get hurt they can be fixed. On the other hand I've seen Dart sportsmans make 500+ rwhp out the box....Paul Chism did this..if you EVER see his book for sale BUY it. He broke some stuff figuring out what works. to me it's also gonna take at least one cam change to optomize this set-up. It is gonna take careful measuring of delta P and delta T to know what's next. All the bench racing OZ and I did didn't matter at all the car (1973 datsun pickup) dictated what we did on so much that we just gave up on pretty. The stuff 240Ztubo does is so nice I would be ashamed to open my hood near him. It just wasn't to be on this project. I'm rambling. If you get serious call me and I'll hook you up with OZ. real nice man, real big car addict. luigi I think this is my longest post. It's cause I love you Denny. Quote Link to comment Share on other sites More sharing options...
Guest Luigi Posted January 10, 2003 Share Posted January 10, 2003 I realized that I didn't really answer your questions. Sorry 'bout the ramble I'd run cast iron heads. They're cheap. And I'm cheap. you're gonna have alot of other stuff to buy. I'd buy a set and run them. No mods no porting. If I had an option, I'd opt for big exhaust valves. Gen 7.0 from accel is a great if pricey system. Buy this part of your build up last. Technology is marching on. Stuff just keeps getting better. Screw the boost. Watch airflow. Someone else will correct me I'm sure, but I think you're gonna need about 375cfm per turbo to achieve 750. Wait, you said rwhp. I think it'll take 500 cfm per. 8.5:1 is a good place to be on compression. not to doggy off boost. try to pick a piston/ head combo that has most of the volume in the piston. like a 64cc head with a dish piston. just my thoughts luigi above all BUILD it. DRIVE it. Quote Link to comment Share on other sites More sharing options...
Guest Zcarsmakemyheadhurt Posted January 10, 2003 Share Posted January 10, 2003 Ahh SBC and boost what a lovley combo. Not alot of people know this but the small block Chevy is my favorite engine of all and I think I have the solution to making big power out of them. The block you have is right on target its strong and with a steel crank you should hold up. On the cylinder heads aluminum is nice but you are going to make big power no matter what you do. The use of a head with a thick deck will let you retain a good sealing surface and if it flows more than a simple 189cfm your good for 1000hp, that CFM is easy to get from almost any head you probable have a set already. Turbos can go in any direction the smallest I would use is a pair of 60-1's or a single T-Series preferably a T-70 or higher. I have sold turbos to guys making 1400hp on stock early 70's blocks with off the shelf brodex heads and Lunati crank rod and piston set up, best thing about it all the stuff was 20yrs old with no porting. That customer used a FAST system and I love that computer for the SBC and Ford but if you dont want to spend $1995.00 on the ECM I would use my other favorit Microtech cool system. Think about a set up like this with a single plane intake that matches what ever head you are using machined for 8 very big injectors and a fuel rail then a down spout adapter with a 2 1/2 or 3inch T-body depending on turbo selection. Go for it man you will be the fastest! Alex Quote Link to comment Share on other sites More sharing options...
denny411 Posted January 10, 2003 Author Share Posted January 10, 2003 Thanks for the input Guys. What about connecting rods? Would I be better off with 6.00" or 5.7" ? I normally would lean toward the 6", but I`m not sure how boost would effect the tourque angle. Lewis, By the way, the Z I`m planning for this is the silver 78 that you looked at. Quote Link to comment Share on other sites More sharing options...
Guest Luigi Posted January 10, 2003 Share Posted January 10, 2003 6.0" is good but you may be able to find a set of heavy duty 5.7's cheap. Keep thinking cheap. good use for that car. leave the body alone and it'll be a great sleeper. luigi Quote Link to comment Share on other sites More sharing options...
denny411 Posted January 10, 2003 Author Share Posted January 10, 2003 Zcarsmakemyheadhurt, How far are you from sebring? My grandparents have a house there. I was thinking about making a trip to see them while I`m already half way. If not too far out of the way, I may stop by and discuss some of my ideas in person. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted January 11, 2003 Share Posted January 11, 2003 Originally posted by eric-z:I thought I read somewhere that cast iron heads were better. I think it is because it retains heat and keeps the temperature in the exhaust gases which helps to spool up the turbo quicker. eric by the way I could be totally wrong on this.... I just thought I remembered reading it somewhere Aluminum heads will conduct the heat from the chamber better, reducing chances of detonation on the next power stroke. Detonation is what will limit your power - aluminum heads will not reduce your exhaust temperature enough to make any appreciable difference in the spool up time. The weight difference alone could make that power difference up I bet! Quote Link to comment Share on other sites More sharing options...
denny411 Posted January 11, 2003 Author Share Posted January 11, 2003 At what boost level does detonation become most problematic? I`ve already got a set of dart cast iron heads that I could use, but if they will cause detonation problems at or around 15lb of boost, I will sell these off and go for some aluminum heads. Quote Link to comment Share on other sites More sharing options...
Guest joeyhammer Posted January 11, 2003 Share Posted January 11, 2003 750 rwhp? oh my god im on the wrong board. i want 250.. lol Quote Link to comment Share on other sites More sharing options...
denny411 Posted January 11, 2003 Author Share Posted January 11, 2003 I will have my NA Hybrid finished this summer. I`m shooting for the summer of 04 for the turbo car. That will give me a year and a half to do research and bargain hunting. In the end, I will probably keep BOTH cars, but DON`T tell my wife that. Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted January 12, 2003 Share Posted January 12, 2003 Denny, the connecing rod length really doesn't matter. The boost is what matters. How much boost you can generate is what makes the HP. The 6" rod will make less side loading on the cylinderwalls, but the shorter piston compression height(aCTUALLY, THE OVER ALL PISTON) will be smaller. So that means a more delicate piston. I'd bet that you could build a motor using you block and crank, and some nice rods(Eagle would suffice) and some forged TRW(sealed power/speed pro) blower pistons. You've seen them a hundred times in the summit catalog. Use studs in the short block, maybe even a short fill with HardBlok to stiffen the cylinder walls. Get those Dart heads with the big chambers. I'm sure they have suffeciant deck thickness. Twin T04B's or 60-1's. That should easily make the hp your after. Put that in front of a stick shift, and bring it to Richmond VA, so I can drive it. LOL. I want to turbo my LT1 in a Zcar bad. I've got it all figured out, but will do the turbo L6 first. Quote Link to comment Share on other sites More sharing options...
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