NA_Z32 Posted January 5, 2007 Share Posted January 5, 2007 i was wondering if early 240z SU's would work bolted onto an L28. would there be any problems with that. i wasnt sure if they would supply enough fuel for the bigger displacement. i have tried and i can get it to run with the choke on, but doesnt run as well with it off. Quote Link to comment Share on other sites More sharing options...
nismoztune Posted January 5, 2007 Share Posted January 5, 2007 I got the same question? Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted January 5, 2007 Share Posted January 5, 2007 I know the early 240 SU's are a pretty popular upgrade for the 260's with the flat tops. There is no reason why they shouldn't work with a 280 or even 3.1 stroker. If it won't run with the choke off then you might have a vacuum leak that the choke is masking. Quote Link to comment Share on other sites More sharing options...
Dtsnlvrs Posted January 5, 2007 Share Posted January 5, 2007 The stock, round top, SU will feed a otherwise stock L-28 just fine up to about 6k. After that and they simply cannot supply enough fuel. Also you should contact Z Therapy and get some SM needles. They will provide the richer fuel curve needed with a 2.8L. Quote Link to comment Share on other sites More sharing options...
roninjiro Posted January 5, 2007 Share Posted January 5, 2007 The stock, round top, SU will feed a otherwise stock L-28 just fine up to about 6k. After that and they simply cannot supply enough fuel. Also you should contact Z Therapy and get some SM needles. They will provide the richer fuel curve needed with a 2.8L. thats what ive done and it runs really good only smoked b/c of bad valve stem seals. now replaced them and it runs extremely well Quote Link to comment Share on other sites More sharing options...
datsunlover Posted January 5, 2007 Share Posted January 5, 2007 I had very little trouble with SUs on my 75 280 until I rebuilt the motor and put a big cam in it (colt cams 510 lift 280*dur. 'road race grind' IIRC..) but they still work.. just not the best. I'm going to bore them out, and get better needles if I keep the L28 in the Z. In my case, it pulls good too 5000, but they run out of steam around 5500, althought he cam is suposed to make power to 6500. The 'choke' on SU's is basicaly a huge dump of fuel, so ussualy if the car wont run well with the choke off, you need to richen it up a bit. I'd say turn them out about 1/2 to 3/4 turns and see if it runs better. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted January 5, 2007 Share Posted January 5, 2007 For what it's worth I don't think SU's run out of fuel on larger engines. I think they run out of air. That's one of the nice things about SU's is that the more air you put through them the more fuel they put out (true of all carbs, but to a greater degree with SU's since they don't rely on accelerator pumps and other fuel circuits). I think some here have shown the SM needles to be very rich on 2.8 and 3.1 engines. I bet a search would bring up more info on that... Quote Link to comment Share on other sites More sharing options...
NCchris Posted January 7, 2007 Share Posted January 7, 2007 http://www.geocities.com/zgarage2001/z.html Good site for SU'd L28. HTH chris Quote Link to comment Share on other sites More sharing options...
XelderX Posted January 8, 2007 Share Posted January 8, 2007 Just joined the forum. This was going to be my first question. I just picked up a L28 out of an 82 ZX for my 260Z. I was hoping to bolt up SU carbs to it. Quote Link to comment Share on other sites More sharing options...
Ericshere03 Posted January 8, 2007 Share Posted January 8, 2007 Yes, the SUs work really well, could be better and they definatly poop out at 5000RPM, i was getting 22-25MPG, i dont think i had modified needeles, the previous owner had redone the motor. Quote Link to comment Share on other sites More sharing options...
Tony D Posted January 9, 2007 Share Posted January 9, 2007 I think the "pooping out" of an L28 with SU's at 5000rpms is more due to the stock cam and poor state of tuning the setup than the SU's! Quote Link to comment Share on other sites More sharing options...
JMortensen Posted January 9, 2007 Share Posted January 9, 2007 To compare I had a medium cam (.490/280) and mine pooped out around 6000, it would go to 7000 but there wasn't much point. Put triples on it and it would slam the 7000 rev limiter. Quote Link to comment Share on other sites More sharing options...
MrFancypants Posted January 9, 2007 Share Posted January 9, 2007 So if the stamp on the block of my 260Z is right, someone dropped an L28 in it. It has twin round top SU's. If the tach worked, I could tell if it crapped out at 6K! Gotta love old cars with unknown histories. This one is full of surprises... - Greg - Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted January 9, 2007 Share Posted January 9, 2007 on the right side of the engine near the top just a litle toward the back thee should be a flat area with L24/L26/L28 stamped on it and then a block # near that. Quote Link to comment Share on other sites More sharing options...
MrFancypants Posted January 9, 2007 Share Posted January 9, 2007 on the right side of the engine near the top just a litle toward the back thee should be a flat area with L24/L26/L28 stamped on it and then a block # near that. Yeah... right underneath the plug for cylinder 6. Pretty clearly engraved L28! Guess my 260Z FSM has a couple more useless chapters now! - Greg - Quote Link to comment Share on other sites More sharing options...
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