ComicArtist Posted October 1, 2011 Share Posted October 1, 2011 So I'm thinking about slowly piecing together a NA motor to drop in the '78 for whenever the L28ET takes a dump or needs a rebuild, and I'm thinking about running this combo: L28 block and rods L28 flat top pistons N42 head 1mm HG Those specs should put me right at 9.9:1 compression ratio, and I'm thinking about a mild port and a small cam. On 91 octane, with maybe a slight tweak to the timing, it should be a fairly streetable combo. Just curious now, is anyone running this kind of setup? If so, what're you doing for a tune? Is it necessary to run full standalone, or can you reliably get away with running stock ECU and tweaking the fuel setup a bit? Thanks! Quote Link to comment Share on other sites More sharing options...
s30red240z Posted October 1, 2011 Share Posted October 1, 2011 Could be a z31 ecu upgrade and nistune! that works fine. Quote Link to comment Share on other sites More sharing options...
ComicArtist Posted October 1, 2011 Author Share Posted October 1, 2011 Hm I've never really looked into the Z31 ECU upgrade. Does it pretty much just involve cutting the harness in front of the ecu and soldering it to the L28 harness? Quote Link to comment Share on other sites More sharing options...
Leon Posted October 1, 2011 Share Posted October 1, 2011 It's never been done. Make sure to document and post the results so that others can learn from it. Quote Link to comment Share on other sites More sharing options...
z-ya Posted October 1, 2011 Share Posted October 1, 2011 With the stock ECU you will have tuning, and potentially detonation problems. Have extra head gaskets handy. I ran basically the same setup in my track car for 5 year with a Megasquirt, around 26 deg of advance, and a 50/50 mix of 93 and 110 as insurance. Blew a few head gaskets along the way. If the tune isn't right, you will be blowing them too. It made 180WHP all day. If it is a street car, consider a P90 or P79. You can run a lot more advance, and run safely on 91 octane. Quote Link to comment Share on other sites More sharing options...
Pyro Posted October 1, 2011 Share Posted October 1, 2011 Going from 9 to 10;1 cr doesn't add much power, maybe 3 or 4%. Not worth the extra tuning mess to me. If you run a bigger cam, then the 10:1 would be no problem. A cam around 290 degree of duration would work fine, but would idle rough and would not be a good match for the stock efi intake. Why don't you build another turbo setup, so when your current engine needs a rebuild then you will already have another turbo engine ready to go? Quote Link to comment Share on other sites More sharing options...
Pyro Posted October 1, 2011 Share Posted October 1, 2011 Here is a "HP from extra compression" calculator. Looks like a 3% increase going from 9 to 10:1, which would most likely be less due to non-ideal tuning for 91 octane. http://www.bgsoflex.com/crchange.html Quote Link to comment Share on other sites More sharing options...
z-ya Posted October 1, 2011 Share Posted October 1, 2011 A cam around 290 degree of duration would work fine, but would idle rough and would not be a good match for the stock efi intake. None of these mods are a good match for the stock EFI (they will work fine with the stock manifold though), period. Sure, maybe you can hack something together with a Z31 ECU and make it work. Or, like I said, you'll be changing head gaskets until or if you can get the tuning right. If you are going turbo in the future, to do it right, you need to run standalone EFI. Now sounds like a good time. Or just do the turbo swap and forget about interim step. Quote Link to comment Share on other sites More sharing options...
s30red240z Posted October 1, 2011 Share Posted October 1, 2011 Hm I've never really looked into the Z31 ECU upgrade. Does it pretty much just involve cutting the harness in front of the ecu and soldering it to the L28 harness? You can swap the entire z31 harness and L28ET distributor, sensors. i mean z31 efi upgrade. Quote Link to comment Share on other sites More sharing options...
Pyro Posted October 1, 2011 Share Posted October 1, 2011 The stock efi intake is designed for low rpm torque. So a 290 degree can is a mismatch for the stock intake and stock efi system. I'm sure the engine would run with a big cam and the stock efi intake, just not ideal. Quote Link to comment Share on other sites More sharing options...
Gollum Posted October 2, 2011 Share Posted October 2, 2011 I agree that the EFI intake isn't an ideal mathc for running a long duration cam, though that doesn't mean it can't be done. So consider me seconding Pyro's view on that. Regarding the Z31, going that route and adding nistune is JUST AS EXPENSIVE AS GOING MEGASQUIRT! In fact i'd say it's even MORE expensive! If you want to do open source tuning and install your eprom yourself it can be done cheaper, but it's still going to be a lot of time and energy just to get a system that works almost as well as megasquirt. If you already have a Z31 ECU and harness available it's a worthwhile option to consider. If you want to run a stock-ish turbo setup it's a very pleasing option as just a plain ECU swap with the MAF sensor is a huge upgrade and will run a stock longblock L28ET very well. No tuning required really. But if you're looking to snag that 10-15% extra power sitting on the table, just go MS or something better even. Quote Link to comment Share on other sites More sharing options...
s30red240z Posted October 3, 2011 Share Posted October 3, 2011 I agree that the EFI intake isn't an ideal mathc for running a long duration cam, though that doesn't mean it can't be done. So consider me seconding Pyro's view on that. Regarding the Z31, going that route and adding nistune is JUST AS EXPENSIVE AS GOING MEGASQUIRT! In fact i'd say it's even MORE expensive! If you want to do open source tuning and install your eprom yourself it can be done cheaper, but it's still going to be a lot of time and energy just to get a system that works almost as well as megasquirt. If you already have a Z31 ECU and harness available it's a worthwhile option to consider. If you want to run a stock-ish turbo setup it's a very pleasing option as just a plain ECU swap with the MAF sensor is a huge upgrade and will run a stock longblock L28ET very well. No tuning required really. But if you're looking to snag that 10-15% extra power sitting on the table, just go MS or something better even. I agree, i am megasquirt user, and is the cheapest way to do your own realtime stand alone, but some people like the stock nissan EFI systems, is up to them the choose. Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 3, 2011 Share Posted October 3, 2011 "but some people like the stock nissan EFI systems" /whispering from the shrubbery:/ Some people like having sex with their relatives as well, it gets the job done, but it's never quite right, you know? /sneaks down to the river for his escape.../ Quote Link to comment Share on other sites More sharing options...
s30red240z Posted October 3, 2011 Share Posted October 3, 2011 "but some people like the stock nissan EFI systems" /whispering from the shrubbery:/ Some people like having sex with their relatives as well, it gets the job done, but it's never quite right, you know? /sneaks down to the river for his escape.../ Hi Tony No body is perfect, LOL, if somebody likes the stock EFI instead megasquirt, other stand alone, etc. they are following the wrong way, i know, i agree, but everybody has different point of view, about EFI resources JWT, Nistune, Calum, electromotive, microtech, haltech, AEM, gotech, live edit, romeditor, megasquirt, etc. P.S. I am megasquirt user. Quote Link to comment Share on other sites More sharing options...
Gollum Posted October 4, 2011 Share Posted October 4, 2011 "but some people like the stock nissan EFI systems" /whispering from the shrubbery:/ Some people like having sex with their relatives as well, it gets the job done, but it's never quite right, you know? /sneaks down to the river for his escape.../ This just about made my evening. ...then I remembered I still haven't ordered my MS-ll. Doh!!! (goes off to hide) Quote Link to comment Share on other sites More sharing options...
2802NR Posted October 5, 2011 Share Posted October 5, 2011 i am running this basic setup and i pretty much agree with what has been said. here's the story L28 block & rods, .030 flat top pistons, we estimated mine around 10.4 with the felpro gasket. N42 with some mild porting .460 270/280 I ran this setup for a year on the stock 77 ecu and on 91 octane without any major problems, totally streetable anyway. kinda fell on its face around 5300. switched to a turbo AFM and z31 TB without much gain. switched to MS and noticed much better throttle response along with low and high end gains. it'll spin to 6 better but still seems like its choking on the stock manifold. i still fight pre-ignition on the hot trackdays, octane boost has been the biggest help there. next step is the custom manifold which is bieng welded now. yes it can be a reliable street setup on pump gas but in my opinion its over building the internals if you plan to run stock externals and fuel control. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.