roughridin89 Posted March 7, 2008 Share Posted March 7, 2008 hey, i have a 78 280z with a couple month old engine. Its bored out to 3.1L, new cam, pistons, crank, head,.....all new. I recently took it out to the track and was expecting much more then what i got. Im a little straped for cash now so i was wondering what people think i should add for the most horsepower. Ive heard many things such as rising rate fule pressure regulater, electric water pump(which would only add a few) and ovcourse NOS, but i rather not mess with that so any suggestions would be great. Quote Link to comment Share on other sites More sharing options...
MJLamberson Posted March 7, 2008 Share Posted March 7, 2008 what did you run? your compression is probably to high and you would need a different cam but have you given any thought to forced induction? Quote Link to comment Share on other sites More sharing options...
roughridin89 Posted March 7, 2008 Author Share Posted March 7, 2008 well i added a cold air intake and new exhaust which i forgot to mention but it ran a 16.65 but some of that might be my shifting. would forced induction help u think? i added a new can and crank one being a maximum crank or cam i forgot which one. Quote Link to comment Share on other sites More sharing options...
Kennysgreen280zt Posted March 7, 2008 Share Posted March 7, 2008 I hate to say this, but thats really slow. Like stock engine slow.... Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 7, 2008 Share Posted March 7, 2008 Not sure what to make of this post. Can you specify what you have in more detail? It looks like a bone stock Z should run a low 17 sec 1/4 mile, so something doesn't seem right. Sounds like you're using stock FI with a camshaft... that might be a place to start. Quote Link to comment Share on other sites More sharing options...
ezzzzzzz Posted March 7, 2008 Share Posted March 7, 2008 The only way anyone here could start to help is to get viable information from you regarding the 3.1 build. We would need specifications for all components used. It could any number of problems. Quote Link to comment Share on other sites More sharing options...
roughridin89 Posted March 7, 2008 Author Share Posted March 7, 2008 ook heres everything i added in the new engine big bore kit p90 heads 3 angle valve job stage 3 performance cam set f54 l28 block 89mm flat top pistons 240z rods ld28 maxima crank comprtition head gasket new bearings new gasket set new oil pump new water pump new timing chin set coated 3-2-1 header new injectors performance flywheel inlarged throttle body and a cold air intake also a performance clutch Quote Link to comment Share on other sites More sharing options...
G.I.jonas Posted March 7, 2008 Share Posted March 7, 2008 would forced induction help u think? You do realize that means turbo or supercharger right?-yea it will help lol. Quote Link to comment Share on other sites More sharing options...
G.I.jonas Posted March 7, 2008 Share Posted March 7, 2008 What do you mean by "new injectors".and as jon pointed out,what are you doing for fuel management if anything-this would be a biggie in making use of what you have. Quote Link to comment Share on other sites More sharing options...
roughridin89 Posted March 7, 2008 Author Share Posted March 7, 2008 ooo my bad i was thinking u were talking about ram air yea ofcourse forced induction would work but would that be good for the engine since the engine is high compression and a turbo or supercharger is not Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 7, 2008 Share Posted March 7, 2008 Reminds me of this thread: http://forums.hybridz.org/showthread.php?t=89812 I see two things that stand out right away. Your cam is too small, and the stock FI can't deal with a cam that's big enough to get the most out of what you have there. Other than that if you're thinking your driving isn't the best it might be a good idea to take it to a dyno and see what it is actually doing. You can see where the air/fuel ratios are, and what kind of power it is putting out now. Although results vary from dyno to dyno this would still be useful info to have, especially if you changed something and then went back and compared the results. Quote Link to comment Share on other sites More sharing options...
roughridin89 Posted March 7, 2008 Author Share Posted March 7, 2008 people have also recomended megasquirt do u think that would also help? Quote Link to comment Share on other sites More sharing options...
m4xwellmurd3r Posted March 7, 2008 Share Posted March 7, 2008 it will help a LOT. the stock efi system is just that. it's stock. it can't make adjustments on its own, and if you change anything in the engine (boring it, bigger cam, turbo etc) the ecu is stupid and basically your car won't run like it should. i think you NEED to megasquirt your car to be able to get the power that the stock system is stealing. Quote Link to comment Share on other sites More sharing options...
roughridin89 Posted March 7, 2008 Author Share Posted March 7, 2008 nice that was very helpfull any other helpfull suggestions just send my way haha Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted March 7, 2008 Administrators Share Posted March 7, 2008 Uhm yeah, that is stock slow. What was your MPH? I’ve seen un touched L-28 powered 280-Z’s running mid to high 16’s in the mid to high 80 MPH range. For what its worth, a “dialed in” bone stock low compression N/A L-28 with the stock L-28 cam, stock EFI and stock throttle valve, ran 14.4 sec @ 97 MPH, in my ’75 280 that weighed 2800 lbs with me and half tank of gas. It did have a header, recurved ignition, light flywheel, and over 3 years of “dialing it in”. I’d expect a stroker with cam, headers, etc to run at least mid to low 15’s, though mid to low 14’s is attainable. If you are using the stock ECU, one thing that stands out as mismatched is the stock ECU and performance cam. The stock ECU does NOT play well with big cams. Best bet is to keep the cam and step up to aftermarket EFI to make use of that cam and get rid of the AFM from the air steam. That and making sure you are able to run between 34-36 degrees total ignition timing will more than likely get you where that motor should be running, which is a lot better than it is now. By the way, what is your total mechanical advance right now? By that I mean, with the engine is at say 3500-400 RPM, vacuum advance disconnected, how much advance is there? Max power will be 34-36 degrees. That 34-36 degrees should be in by no more than 3000 RPM, more like 2500 rpm or so. If you don’t have a dial-back-to-zero timing light to verify this, typically having the stock distributor set at between 15-17 degrees advance at idle, vs the stock 10-12 degrees is ball park, so long as the mechanical flyweights are working and allowing the timing to advance as RPMS rise. If the engine rattles/pings at this timing setting with pump gas, then your comp ratio is too high and possibly mixture is little lean, as such you'll have to back timing out till it doesn’t rattle anymore, which will be giving up power that engine is capable of producing. Good luck, Paul Quote Link to comment Share on other sites More sharing options...
m4xwellmurd3r Posted March 7, 2008 Share Posted March 7, 2008 i think for now you should just dyno it to see where the power is now, then scrap all the stock ecu components and megasquirt it. iirc just putting a bigger cam into a stock engine will cause it to not run like it should because the ecu has no way to compensate for the change. Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted March 7, 2008 Administrators Share Posted March 7, 2008 I need to back up. Sorry about that. As Jon mentioned above, first off verify your timing and AFR’s are in check using a dyno. That will give you a good solid baseline for verifying if changes in tuning either improved or hurt, and where those improvements were made or lost. If your timing and AFR’s are not in check, just throwing parts at it won’t help. Tune tune tune… That is how I get a BONE stock, 8.1: compression L-28 in 2800 lbs Z car with stock EFI, stock throttle stock cam, to run 14.4 @ 97. It took me 3 years of tuning, but for a stock L-28, it ran REALLY well, and even got 28 MPG on the freeway! Again, take it to a dyno and verify AFRs are correct and you are getting adequate ignition timing, (34-36 degrees btdc) by 3000 RPM and up. Quote Link to comment Share on other sites More sharing options...
panachedk Posted March 7, 2008 Share Posted March 7, 2008 Braap, that was a l28e or l28et? that sounds like what i want! Quote Link to comment Share on other sites More sharing options...
MJLamberson Posted March 7, 2008 Share Posted March 7, 2008 Ive got a solution... ditch the bumpers... oh, and ditch the 2+2:wink: Quote Link to comment Share on other sites More sharing options...
(goldfish) Posted March 8, 2008 Share Posted March 8, 2008 ooo my bad i was thinking u were talking about ram air yea ofcourse forced induction would work but would that be good for the engine since the engine is high compression and a turbo or supercharger is not What compression are you at? From what I read that would be mid-high 8's ( I think) which is still ok for F.I. Along with Braap and jmortensen, I would then look at the intake manifold next. The stock EFI one is the next restriction. Quote Link to comment Share on other sites More sharing options...
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