L24 Carb limitations?

[red_dog007]

With sticking with carbs on the L24, what can the performance be increased too? I know that if I picked up an L28E/T or EFI my 240, the possibilities are almost endless, but I dont want to do that and I am not sure much if any about carb limitations.

I am wanting to get at least 200hp out of the engine as cheap as possible. I am also looking at one day getting triple 45/50mm carbs, but I have heard from some people that it makes little difference for the amount of money that you throw into them.

I know that I could bore/stroke out the L24 to a 2.8L, and with some mods get a bit above 200hp, but I am still not sure if I wanna do that or not.

What are sum recommondations from you guys to help me get to 200hp and one day 250hp. If I could get up to 250hp one day on the stock engine w/ carbs, I would be a happy camper.

I have fianlly figured out that I do not want to do an engine swap. What I want to do is keep my 240z as stock as possible with it pushing atleast 200hp and more so 250hp.

I know that it wont do much, but I am at least starting off with ngk plugs/wires and soon I am ordering an Ignitor II and a Flamethrower Coil. Also might be picking up an exhaust from a member here.

[dscott@shouri]

If your 240Z has a matching engine. I would suggest not stroking it. Remove it and get another engine to play with. Ie get a 280Z engine and stroke that. Or just get a 280Z engine.

[Arne]

Frankly, red_dog, I think you're barking up the wrong tree. Getting a true 200 HP from a streetable naturally aspirated L24 will be very hard, and 250 close to impossible. If you do get it to 200, you'll have an engine with little torque or power at low RPM, a radical cam, etc.

My personal opinion is that if you really want more than say 175 HP, I'd pull the stock motor out and put it in storage somewhere, then start with an L28 and do it right. Say, an F54 block with flat-top pistons, N42 or shaved P90 head, medium-hot cam, good exhaust and fresh round-top SUs. That should get you in the 200+ area.

[John Coffey]

The top ITS 2.4L L6 engines ("stock" engine internals, stock SUs) make around 205hp at the crank and are very streetable. The EP 2.4L engines make around 250hp with SUs, 12:1CR, .500 lift cam, etc. They are fairly streetable if you run the right fuel.

[xray]

Red Dog:

Wait---did you say cheap?

1) Triple carbs: $1800 rebuilt or $700 on Ebay plus $5-700 in parts to get it running right

2) Performance Headwork: price predicts quality and results. $1000 or more (Rebello, et al)

3) SUs: cheap to rebuild, $700 for refurbished. $850 for 50mm overbored ones.

4) OR, a 280ZX L28ET and accessories for $5-800. Give or take a few bucks.

...at least you saved some money on leaving the block alone...

So, what does cheap mean to you?

You have to understand that this is 35-year engine technology we're talking about here. It has inherent limitations which are expensive to overcome, especially if you try to keep the stock displacement and induction. Remember, HP is just a number for dyno queens and wannabes to throw around to look cool. You have to consider gearing, driveline inertia, suspension, and (wait for it).....driving skill.... when evaluating your setup. I think that may be what you're really after, yes? A fun car that you can go fast with, turn quick, control well, stop on a dime?

I apologize if this sounds confrontational. Without altering the block or raising compression to 110-octane race fuel-only applications, anything above 200HP is almost impossible. To get the best NUMBERS out of this engine series, you have to be willing to go pretty radical. Stroke it out. Turbo. Whatever. Otherwise, be ecstatic with 205 crank HP. In a car which weighs 2400lbs (or less), with proper gearing, suspension, tires and skill you can do 13s at the drags and beat that Mustang in the turns.

Good luck,

Steve

[dspillman]

Red Dog,

Come on down Sunday to look at that exhaust.....I've have my recently retired ITS "racing" engine in the garage, that'll still get 160 at the Crank at least, if interested in a truly low cost performance engine. If you combine that with the E-42 head I have laying in the corner, it would really sing!! Let me know if interested. Compression in the 178-182 range when last checked back in summer.

Pick up a 3.9 diff, zx 5-speed and you'll be ready to roll.

Cheap is a relative term somewhat....:cheeky:

david

[jmortensen]

Don't start with the L24. Start with the 16% larger L28 and build that up. Should see 16% more hp than a comparably built L24. Then throw out the rule book since you're not limited by it and get a larger cam (that EP cam would be a nice one for a hipo street engine), up the compression, port the head, and get a good induction and exhaust system. That's what I did, and my L28 makes ~240whp.

Oh, and for the record, the triple 44's made a HUUUUUUUUUUUUUUUUUUUUUUUUUUUGE difference on my car. If I were to guess I'd say 40 whp. So that would put it right around 200 whp before the triples. That is just a guess though...

[zguitar71]

I rebuilt my tripples (Mikuni's) for $36, the cost of three rebuild kits (Mikuni brand). I did not need to do anything else like jetting but even if you do have to get different jets and other things a good set of used tripple should not cost $500-700 to rebuild. For $1800 you can get a new set of tripples (45mm), TWM intake and all the linkage and air filters, rebuilt carbs are not $1800. And yes Tripples do make a big difference. With the right head work (from someone like Rebello) you should be able to get 250 HP from a 2.8 with SU's and closer to 280+ HP with tripples (45mm) and still be streetable (no race fuel).

[Arne]

All this is darn good info, but the way I interpret

"I am wanting to get at least 200hp out of the engine as cheap as possible..."

would rule out things like Rebello heads, balanced internals and the like. I still think that 200 HP out of an L24 on a budget is not realistic. I failed to mention the budget part in my first reply, my bad.

[240ZX]

Speaking of Dave Rebello....he offers a 3.0 L6 w/50mm Su's that puts out 285 HP @ the crank. Nice package! About $6500.00 worth.

Tom

[red_dog007]

See, thats what I was wondering if I could get 200hp for cheap, but I guess not.

Sorta figured that this engine had limitations unless you went all out on it.

I think that I will do a little more research then. Triple carbs have always looked very tempting to me. Other then a kit that comes with everything, would I need to modify anything else to get not get a bottle neck from the carbs?

[Huw]

if you're driving it on the street....I'd stick to SU's (at least in my opinion)

they can be rejetted and modified for larger displacements and better flow and they seem to be inherently more flexible than some of the tripples (less stuffing round too!).

from my experience the tripple tend to bog down a little in normal driving (maybe weren't set up right), it only when you open them up that they come into their own.

Anyway, not a mechanic or anything, just my 2 cents.

Huw