zeiss150

Hey Z people, Merry Christman everyone! I'm looking for someone with a turbo Z that has at least 9:1 CR. I've been reading my a$$ off on the old posts about turbos and high CR and it's just left me with more questions than answers. So I'm looking for someone that has a 9:1 CR turbo that can walk me through the do's and don'ts of that kind of set up. Anyone up for it? Rock on Z people thanks Matt

Don't feel bad I had that same question when I built up my L28. If you look on the inside diamiter of the gear you will see the "chamfered" (beveled) edge. When I was stumped on this one it was because I was looking at the outside edges ... they're both chamfered! Good luck Rock on Z people!

Hey 73turbo thanks for the answer.... Sorry to read about all of your head gasket trouble. How much HP were you looking to get out of that bad a$$ engine you built.

stupid question here... can you re-use an HKS 2mm steel head gasket? I have one on right now and im thinking about changing out my head for P-90 I was just wondering if the steel gasket can be used twice? Just a dumb question.... anyone got a smart answer?

gavin, check this one out ... I like it better http://flzclub.com/downloads.htm

Hey gavin, That MN47 head with flat tops will give you something in the ball park of 11.3:1. Thats pretty risky, but you are running megasquirt so you can really controll your air fule raito. the 1mm head gasket raises the CR about .3 or so if I remember correctly compaired to stock head gasket. now that I think about it that 11.3:1 CR might be with dished pistons so flat tops might be more like 13:1, a bomb waiting to happen. Rock on Z people

Good times .... the N42 head and the N47 are almost the same (they have the same CC's), the only difference is in the exause ports. the N47 has rounded exaust ports with steel liners that heat up to burn up unburnt fuel in the exaust gasses. its suposedly a great flowing head. On the other hand the N42 head is legendary for it's performance. If you decided to sell the N42 you should get close to $200 bucks for it. Which ever head you go with make sure you rebuild the thing. those brass valve seats suck and a new 3 angle valve job wouldn't hurt. I'm running an N-42 head with flat top pistons and SU carbs with headers and electrick dizzy and my Z is awesome fun to drive. Good luck, and keep us posted on your build. Rock on Z people

hey Gavin, The 75-80 L28's all came with "dished" pistons. You can put "flat top" pistons from an 81-83 non turbo into the block and raise the CR with the N-47 head to 9.82:1 In my personal oppinion a great CR for a Naturally aspirated L28. If your every thinking about going "turbo" that might be a the edge of a do'able CR. When you say you have "both blocks" what do you mean? the only two L28 blocks were the F-54 and the N-42 the N42 cam with dished pistons the F54 had a choice of dished or flat top depending on if it was turbo or NA. do you mean that you have an L26 or L24 block? Also what are the 2 different heads you have? N-47 N-42? N-47 P-79? Different heads can give huge differences in CR. I hope that cleared things up for you Rock on Z people

Hey gavin, we need more info. in order to answer your question. for example... are you going to use flat top pistons or dished pistons are you going to bore the block, if so how much also the N-47 head came standard with the N-42 block with dished pistons and a compression ratio of 8.29:1 from 75-80. if you're woundering if an F54 block would give you different compession with an N 47 head the answer is no. All of the L-28 blocks have the same bore and stroke. different heads, pistons, and head gaskets will affect the CR the block doesn't matter (unless it's an L24 (e31, P30) or L26 (P30)). I hope this answered some of your questions Rock on Z people

Hey TonyD, do you run 15+ lbs with stock CR or are you putting that much boost through 9 or higher CR? I'm trying to build a beautiful, somewhat stock 240Z that will KILL just about any stock "sports car" on the road. Rock on Zpeople

Dude check this site out!!!!!!!! http://zacksz.homestead.com/projectboost.html this has all the answers to what is involved in a VG swap... enjoy! rockon z people :zockon:

Im going to be running 9.2:1 CR ??:. From all the reading i've been doing, and believe me it's a lot, as long as you keep the air fuel raito right, along with a "great" intercooler and great engine computer (megasquirt or simillar) you can run enough boost to make your car go 0-60 in holy$hit. I plan on starting with 7lbs of boost to start ... and I'll turn it up untill I sence(this is where my spidey sences will come in handy) there is a problem or 12lbs which ever comes first. Keep us updated with your progress Rockon Z people

Hey RaiZed, I feel your pain! There are some guys on this site that think every question should be searched and if you don't find what your looking for then you must have done something "wrong" in your searching. I tore into some dude once for giving me the "you need to search" line. Keep the faith though, for every a$$hole that tells you to search, there are hundreds of very helpfull people. I don't know much about the VG engine but I agree with vashonZ for what you would spend putting in the VG you could build a 300+ RWHP L28 turbo. Just grab some of the stuff off the VG and rock and roll. If I were you I would rebuild the L28T short block with flat top pistons (instead of dished) with a 20thou over bore, and a 1mm felpro head gasket gives you a CR of 8.8:1. That should make it really quick off the line and once the T-3 kicks in ... watchout! ... Get yourself a nice IC and some bigger injectors along with megasquirt, oh yeah and lets not forget the 60mm throttle body and you'll still spend less than you would with a VG swap. does 0-60 times of around 4 sec. sound fast enough to you? So I guess you need to weigh cash vs. HP. This is all just my 2 cents and it's probably worth that much, but I hope it gave you enough info to help you make a choice. let us know what you decided to do and don't sweat the "just search" jerks there's more of us than there are of them. Rock on Z people

Hey DJ paul, Thumper is right the P79 was only on NA heads. your CR's are a little off P79 with flattop = 8.52:1 E31 with flattop = 10.21:1 N47 with flattop = 9.82:1 if you used the the P79 with a 1mm HKS(steel $200 ) head gasket you can get the CR up to 8.71:1 I got these CR #s from the Lengine calculator it's an awesome program. The P79 is the one that I would go with it suposedly flowes the best and it will give you the best CR for a turbo application. the E31 would be a disaster, It has the small valves, not good for a larger displacement (2.8 vs. 2.4) short block, not to mention the 10.21:1 CR way to high for a turbo IMHO. The N47 is a great head but why bother when you have the P79. The link that thumper put down is awesome this site has great info too http://geocities.com/row4navy/head2.html Good luck and let us know what you go with. Rock on Z people P.S. if you want the Lengine calculator just google it.

The headers will smoke for about an hour or so or untill the paint burns off. MSA uses regular paint for there headers, I guess they didn't want to pay the extra $5 for high temp header paint. As far as weither or not you are running on 3 cylinders, Im no expert but it probably wouldn't run on just the front three. This is just a guess but the front 3 might be hotter because your front SU is running to lean. I could be totaly wrong on that but it's just a guess. richen up the front carb a bit and see what happens. if it's still hot... well then you know thats not the problem. Good luck. Rock on Z people

Hey JessZ, I have that cam in my Z and it performs great. I have an L28 motor with an N42 head. If you want to use that cam in an L24 I don't see why it wouldn't work, (keep in mind that im no expert on cam profiles and how they differ with different displacments). My Z makes power from 2000-6000 RPM It really kick's in at about 4K. That cam with SU's, An N-42 head, headers, 2.5 inch exaust, electric dizzy and Im sure your L24 will make some great power. Of course none of that stuff would be original to an L24... so why not just move up to an L28? Or here's a crazy Idea ... turbo your L24. I'd say if you want better HP get rid of that E88 head and move up to an N42 or a shaved P90. The better flowing head with that mild cam will rock your L24. Good luck and keep us posted on what you do Rock on Z people

hey drifter ... check out your local Napa auto parts store or call (800) 633-6331. MSA has them in stock for $39.95. http://www.zcarparts.com. It doesn't look like the 280zx will fit... 70-78 are the same.

Hey J ... I don't know how much you want to get into your engine but I think your best bet for a fun N/A car would be to rebuild your short block with flat top pistons and throw the P90 head on there and from what I've read the P90 head was the best flowing of all the heads. That would give you a CR of 8.52:1 (acording to the L engine calculator). with that compression you would be able to run 87 octain with no problem and still have a "zippy" little car. While you're at it through on a 60mm throttle body(from a 240sx) on instead of the 50mm TB that is on the car now and that should make your car a lot of fun to drive untill you turbo it. If you don't want to rip into the short block then just through the N47 head on there. it'll work great im sure. rock on Z people

Hey Eric, as if you didn't have enough to consider... I did a build up with an F-54 block .20 overbore flat top pistons, N-42 head and a 2mm HKS head gasket. using the L engine calculator I figured that gave me 9.2:1 CR. I'm running SU carbs with SM needles, I also have a schnider cam 460 lift 270 duration. It's a really fast little N/A engine, spins up to 6500rpm, with power in the blink of an eye, and I don't have detination problems on 91 oct. It's great fun to drive and it was an easy, "cheap" build. I have no idea what it's HP #'rs are but but Im ready for turbo. With the engine that I have, I should be able to run about 12lbs of boost safely with the proper engine management and IC. What I'm saying is ... think about the future.... turbo will become more and more interesting. Good luck with your build and let us know what you do. Rock on Zpeople P.S. If I had it to do all over again I'd build a straight up turbo... you just cant get the kind of HP with a N/A engine that you can with a turbo. If you think you don't know enough to build one, this site should inspire you. 3 months ago I didn't even know how a turbo worked ... thanks to this site I just rebuilt a Nissian Z31 T3 turbo. You can do it! This site can help!

Hey Braap ...Can't you just leave the stuff on the bottom alone and get ride of the EGR "mount" and then weld that hole? you can't see the bottom of the intake anyway when its on the car. Is there a performance reason to cut the bottom part off? I'm not going for a show car I just want it to be clean. Also... the pair shaped intake... do you fill the top part with weld then grind it to match the 60mm TB, or do you just weld a patch over it? and do you have a picture of it finnished for a 60mm TB? Thanks, Matt Rock on Z people

Hey guys, Can you use an "EGR" N42 and still clean it up pretty good? Also if you're using a 60mm throttle body how do you deal with the "pear shaped" TB opening vs. the round TB? I know there must be a solution to this problem. Rock on Z people

have you tried megasquirt? It's about $200 and it will cure all of your FI problems. With Megasquirt you can pull your old FI harnes and through it in the trash. I know you're really into the carb idea but I would encourage you to look into the FI options because if you did decide to go turbo and you had a carb setup... well ... they seem to be a bad combo. right now I'm running an L28 with N42 head, headers, electronic dizzy, and SU's. It runs really well but I want to go turbo ... so ... FI it is. Also cold starts suck and carbs have that "lumpy" idle. If you ARE going to go carb like you say then I would go with the SU's. Just buy the SM needles and they perform really well ... better than any downdraft carb. if you really need more from your carbs than the SU can deliver, then try tripples or Jaguar SU's. I hope I'm helping you with the limited info that I have. Rock on Z people Matt-

are you just trying to save money buy using a carb? cause I don't think it would be any cheeper. the Holly is a down draft carb and the SU's are side draft and I think I remember reading somewhere on here that the down draft carbs suck for the L28 engine. You'll also need a special intake manifold MSA sells one for $440.00 plus thottle brackets for $60 bucks. You can pick up an N42 FI intake manifold from a 78 z for $35 at a pick a part. Good luck J.T.

Akeizm brings up a valid point about not being able to get 275 with 13lbs of boost. it seems to me that some guys here can get 300rwhp with 15lbs of boost and some guys can only get 230 with 15lbs of boost. The point is if you want a 275rwhp engine then make sure you build it from the ground up. find a member here that has the hp you're looking for and then copy excatly what they did. Good luck! Rock on Z people

if your looking for more power turn up the boost... with an IC you can easly go up to about 13 psi ... I would guess that would get you in the neighborhood of 275rwhp or so I would guess. The NA cam should be just fine for your turbo motor.