goal: 200+rwhp L6 NA

[janaka]

I'm looking to up the power of my 280z. currently its a 162rwhp on an L28 motor. .460 lift cam, dual SU's, header, 2.5" exhuast. F54 flattop block and P79 head with mild port work from previous owner. CR 8.8:1

 

there is a guy locally selling a fresh rebuilt F54 flattop with N42 head (again mild port work) and small cam.

 

I'm told the F54 and the N42 will net a CR of 10.4-10.5:1, is this correct? If so, if I drop in a larger cam (say in the .500 lift region), lots of port work (whitehead performance specializes in L6 heads local to me) and add Triples would that get me in the 200+RWHP range?

 

The motor is going for about $1500, cam + head work prolly in the $2500-3000 range and then triples for another $800ish. So about $5000 for it all, give or take.

 

This leaves me with my entire motor to either sell to re-coupe some costs or have to drop in if I need to later on, or build for another Z down the roads.

 

Thoughts or comments?

[badjuju]

Uhh, before the search bashing begins i'm just gonna go ahead and say don't spend $5000 to get 200 hp out of an l6.

 

If you have 5k to spend on your car, go in another direction. turbo charge it. or if you absolutely want to go NA, do a chevy swap. please. do not spend $5000 to aim for 200 at the wheels

[naviathan]

The only thing I'm going to say here is, don't spend $1500 on an engine. That's just insane.

[WEBEZEEed]

If your SUs are stock there is 20-25 H.P. hidden in them with some air flow improvements, just some of your labor& not spending any money.

[johnc]

Labor is the best place to spend your time and dollars on when trying to build horsepower into a NA L6. Well built L24 engines can make 200+ crank horsepower on stock internals with SUs. With very careful assembly, some good head work, thoughtful parts selection, and proper tuning you should be able to exceed your goal with an L28. $5,000 is a good budget for a proper bottom end and head build.

[JMortensen]

Maybe I'm influenced by the huge hp numbers thrown around here, but it doesn't seem like you need to be all that careful when trying to get 200 whp out of an L28.

 

I would think that you could get very close if not reach your 200 whp goal by installing an N42 and going with a larger cam (something in the .500/300 range). You'll need to do some modifications to run a cam that big, like installing aftermarket springs and retainers and shorter valve stem seals, but the bigger cam would be worth the effort.

 

If that didn't quite get you there, triples certainly would. My opinion on triples is forget about the 40s, and go with the 44's or 45's. I think you'll be really close to your goal without them though. Ported SU's are another option, but I think the triples will ultimately make more power although they're harder to tune.

[Dragonfly]

Maybe I'm influenced by the huge hp numbers thrown around here, but it doesn't seem like you need to be all that careful when trying to get 200 whp out of an L28.

 

I would think that you could get very close if not reach your 200 whp goal by installing an N42 and going with a larger cam (something in the .500/300 range). You'll need to do some modifications to run a cam that big, like installing aftermarket springs and retainers and shorter valve stem seals, but the bigger cam would be worth the effort.

 

If that didn't quite get you there, triples certainly would. My opinion on triples is forget about the 40s, and go with the 44's or 45's. I think you'll be really close to your goal without them though. Ported SU's are another option, but I think the triples will ultimately make more power although they're harder to tune.

 

I agree with what Jon says but what you have to consider with this you are looking at peak HP rather than broad HP which makes the car much more enjoyable to drive. If you want a nice flat torque curve and HP curve with 200 or more WHP you are going to have to spend some money and time (probably alot of both).

 

That makes the one for sale at $5000 much more reasonable (for an L series engine), but beware that what people tell you and what is really there (inside the engine) can be two different things. If "I" were going to pay that much for that engine I would have to see the blue print sheet (or build sheet), dyno sheet, machine shop reciepts, and manufacturer data for things such as forged pistons etc. that may have been installed into the engine. Personaly I would not trust someone on their word alone because if they have that into it they will have some documentation to back it up.

 

Dragonfly

[Tony D]

I'm with Miles about being wary of what people tell you, insist on the receipts and maybe even opening up some stuff to check it out before you buy.

 

I bought a Corvair one time where the P.O. told me 'cam, forged 0.060", balanced and lightened rotating assembly' I was like "yeah yeah yeah, no receipts or shop orders it don't mean anything, I'll give ya $1500 for the car as is..."---anyway, got two years down the road and pulled the fan cover to fix a leak and was shocked to find the guy was actually telling the truth! Isky Cam, 060" TRW Slugs...and shotpeened/lightened rods! I ended up taking photos of everything so later I could prove what was actually inside the engine.

 

It was an 'anomaly' as far as I've seen. Engines can run so well with just some head work and a cam, people think there is a LOT of work 'on the bottom' and end up getting burned. Caveat Emptor.

[Daeron]

I would say to look into shaving a P90 head, rather than using an N42, because my understanding was that to run well at higher CR the N42 chamber needed some reshaping, and thats the expensive part of head work..

 

If you were to take a P90 head and do the "shave and shim and use N series valves" mod then you could get up into the low 10:1 compression ratio.. throw a set of triples on it, and select an appropriate camshaft and valvetrain, and you ought to easily be in the 200-220 ballpark without much more intense work.. if you build it right, you might get there with much less. Better spark and fuel accommodation can add alot to an engine's potential.

[Bob_H]

I would say to look into shaving a P90 head, rather than using an N42, because my understanding was that to run well at higher CR the N42 chamber needed some reshaping, and thats the expensive part of head work..

For the power requirements he's asking for, a stock chamber N42 will work fine, if not better. A good choice of camshaft, maybe some light port work and a good quality valve job and its a good start. You have to shave the P-90 to get the compression ratio up to a decent amount to make that kind of hp,(possibly requiring shimming, etc..).

-Bob

(former and current P-90 fan, but strong believer in the N-42)

[gogriz91]

Great write-up by BRAAP on L-series cylinder heads. Might help get you pointed in the right direction if you haven't read it yet.

 

http://forums.hybridz.org/showthread.php?t=104420