Just picked up 73 240z. Should I rebuild the L24 or swap to something else???

[VQ35DETT]

Dome-top (as opposed to '73/'74 flat-top) SU carbs will be absolutely fine for the street. Can't see spending the $$$$ for the six-butterfly FI setup, but if money's no object...

So the L28 sounds like the more reasonable way to go...

Dan Baldwin - Are you running the same motor? I see on your sig it says 3.1??? And 255? Thats good enough for me.

Dan do you have pix of your motor/engine bay that you can share with me?

[VQ35DETT]

Oh, Dan, btw, here is the link to a motor package for the 510/240Z >>> http://www.racetep.com/xmasspecials.html#dat

Do you think it's worth it? Pls give me your opinion on this one. Thanks!

[Dan Baldwin]

No pics of the engine compartment (it's ugly, anyway). Basically it's an 11:1 CR 3.1 with Sunbelt ported and cammed (~310deg/.550") N42 head, 3x2 45mm carbs. Two years ago it dynoed at 235rwhp. Last year after a rebuild, it made 255rwhp(!), but earlier this year it only did 238. I've been robbed!

From the TEP website, you thinking about the carbs or the rebuild kit?

Depending on what you want to do, you might not need forged pistons. FWIW, I'm using Nissan KA24 cast pistons in my motor. Unless you're going 13:1 CR, or turbo, or over 7500rpm, I don't think forged pistons are needed.

Regarding carbs, you can get used ones cheaper, but then they are of course, USED. I got mine for $600 used, then spent ~$280 on an ITG air filter and backing plate, yow! Used or new, carbs will get you way more hp/$ than the super-duper 6-butterfly FI setup.

[VQ35DETT]

Thanks Dan for your reply. 238?!? Sounds good, although the intial 255 was better. And was your car dyno'ed on an engine dyno or car dyno? And you are running 11.1 cr on 91 pump gas correct? What is the highest you think we can run compression wise on 91 pump gas? On hondas, we have did 12.1 and retard timing all the way to run on pump gas. And some 1.8's that we have built were dyno'ing at 205-215 to the wheels. But again this is honda's running natural aspirated. What is the max hp have you seen with guys like yourself building N/A motors on carbs and pump gas? I really want to research all my options. Thx again.

[Dan Baldwin]

238 at the wheels. I agree, I like 255 better! Hopefully the 255 is the dyno reading ~3.5% high and the 238 is the dyno reading ~3.5% low, I wouldn't like to think I actually lost that much over the course of a year. FWIW, the plots are pretty much off by the same amount everywhere, down ~7% throughout the rev range.

I'm running 11:1 CR on 93 pump. I wanted to aim for 11.25:1, but it wasn't in the cards even with customized gasket thickness (piston/valve clearance issues). I don't think you could do much more than that with a big-cammed (mine's ~310/.550") L6 on pump gas. *Maybe* 11.5:1, but I wouldn't risk it. 1.8 liter Hondas have much smaller bores, allowing higher compression ratios. 600cc 4-cyl motorcycles are running 13:1 stock now!

205-215 to the WHEELS, out of 1.8 liters, on PUMP GAS?! What was that, at like 8800 rpm? Me wanna make a mid-engine CRX with one o' those engines!

I don't know of anyone making more than myself on pump gas, but I'm sure they're out there. John Coffey is making 287 at the wheels with a 3.0 liter with 13.4:1 CR on race gas. No-expenses spared Sunbelt-developed and -built motor, through a $$$$ straight-cut-gears race gearbox and Quaife rear end. That's probably about as much as the most serious GT-2 L6s make/made.

[VQ35DETT]

Yeah, if I could push anywhere around 230+ on a L6, that would be nice. Oh and can't forget to mention, pump gas. Just too bad our highest is 91 here. Sucks major arse!

Yeah, if you need a HOnda motor built, I can refer you to Jerry Built Racing. He's a personal friend of mine that I known for years. He's build some of the craziest honda street/strip motors around. He's well known in the street races here in southern cali. His most recent 2.0 vtec motor pushed out 261 to the wheels which helped his hatchback run 11.7 on the quartermile.

Here's proof that a 1.8 motor on 91 pump gas can do >>> http://www.importreview.com/dyno/1.8/group2/ITR2.gif

Jerry built racing >>> http://www.jerrybuiltracing.com/

John Coffey's car sounds pretty bad arse! But yeah, money is an issue right now.

BTW, Dan, do you know where I can purchase a 4 point or 6 point rollcage? I want to put one on, before I get the whole car worked and painted. Let me know if you know of any shops and/or costs. Thanks!

[Dan Baldwin]

I bought my bolt-in 4-point roll bar from Kirk Racing in (Birmingham?) Alabama. Only ~$250 IIRC. I needed it for time trials competition, I confess I just bolted it in with some improvised spacers and backing plates, not exactly a professional job:) But their bar does pretty much fit, and the main hoop bolts to the floor, not the deck. Rear feet bolt to the wheel housings in front of the strut towers.

[zeiss150]

All of these threads and not one mention of a turbo L-28. I have a N/A L-28 build up, and its a great every day driver. I used to have the L-24 but I swaped it out and what a differance. The added torque is great. I'm probable putting about 150 or 160 to the rear wheels (Just a guess, I haven't dynoed yet) and I can blow people off the line all the time. Now my next engine swap will be to a 82 ZX turbo. If you pull one straight from the junk yard with the Borg warner tranny It might cost you about $700. and a stock turbo L-28 will give you over 200 to the rear wheels with no mods at all. If you raise the boost and get a better computer, bigger TB, bigger injectors, Horse power can get really impressive. There is a guy on this site that was putting 360 RWHP and about 380 lbs ft. of torque from an L-28 turbo. If you want big HP I would go turbo not a 3.0 or 3.1 they're super expensive and they dont have the HP and torque potential that the turbo has at half the price. Also with the turbo the compression ratio is really low 8.2:1 I think so 91 octain will work great. Think trubo!!!!!

Rock on Z people

Matt-

[Gav240z]

I'm not going Turbo because here in Australia it's not as economical as it is over there. I'm also sticking the an N/A motor because it's not as troublesome and less things can go wrong. So that only really applies to those who are reading in the US or Canada my motor isn't done yet but when it is I'll be sure to let others know ~what power she makes and how much it cost.

[Ed]

I'm building a L28 to put in my 73. This is what I've got.

Block - F54

Pistons - Flattop

Head - N42 shaved .040". 3 angle valve job, match ported to the intake.

Headers - 6-1 with 2.5" all the way back to a flowmaster.

Carbs - Dual SU's with modified needles

Ignition - stock electronic from a 81ZX. Maybe upgrading to a MSD 6a?

Cam - undecided.

I haven't figured out my combustion chamber cc's yet to get an accurate compression ratio.

Can some of you guys post what you have?

[VQ35DETT]

I bought my bolt-in 4-point roll bar from Kirk Racing in (Birmingham?) Alabama. Only ~$250 IIRC. I needed it for time trials competition, I confess I just bolted it in with some improvised spacers and backing plates, not exactly a professional job:) But their bar does pretty much fit, and the main hoop bolts to the floor, not the deck. Rear feet bolt to the wheel housings in front of the strut towers.

Sounds nice! I gots to check it out. Thx.

[VQ35DETT]

All of these threads and not one mention of a turbo L-28. I have a N/A L-28 build up, and its a great every day driver. I used to have the L-24 but I swaped it out and what a differance. The added torque is great. I'm probable putting about 150 or 160 to the rear wheels (Just a guess, I haven't dynoed yet) and I can blow people off the line all the time. Now my next engine swap will be to a 82 ZX turbo. If you pull one straight from the junk yard with the Borg warner tranny It might cost you about $700. and a stock turbo L-28 will give you over 200 to the rear wheels with no mods at all. If you raise the boost and get a better computer, bigger TB, bigger injectors, Horse power can get really impressive. There is a guy on this site that was putting 360 RWHP and about 380 lbs ft. of torque from an L-28 turbo. If you want big HP I would go turbo not a 3.0 or 3.1 they're super expensive and they dont have the HP and torque potential that the turbo has at half the price. Also with the turbo the compression ratio is really low 8.2:1 I think so 91 octain will work great. Think trubo!!!!!

Rock on Z people

Matt-

Thanks Matt. That sounds good. But do they make mounts for it? I'm a newbie here, and my mechanical knowledge only comes from hondas. Give me some more info on this swap. Thanks!