best way for 20-30 crank hp build increase

[hooahh3]

yep. so i'm figuring out now. But at the time i was also more convinced it was a spark issue not fuel. so i headed that way first and came back to fuel. chose the wrong path.

[turbogrill]

the inherent weaknesses of the engine design.  

What would these be??

[Mack]

Some ways for more HP...  easiest to hardes.

 

A cold air intake/aftermarket air filter/mod your stock air box.

 

2.5 mandrel bent exhaust.  with the proper muffler, it SOUNDS awesome as well.

 

a header.  although it wont do much other than sounding cool without a lot of other work.

 

A cam.  easy, bolt in power if you know how to work on these engines

 

valve bowl work.  Just blend the valve bowls into the upper portion of the seats if you ever have it off for a headgasket. 

 

more compression.  flat tops and the .080" P79/p90 head mod.  Or the maxima N47 head.

 

Megasquirt.  one of the BEST bang for the buck mods out there.  hands down.  definitely NOT for the inexperienced mechanic or tuner.  

 

I did all of these, except for the cam and the header.  I also added a 60mm 240sx TB and got a bit crazier with my cylinder head porting on a maxima N47 head. My car (1980 2+2) went from a high 17 / low 18 sec stock 1/4 mile to a VERY low 15.  That is on a puny stock cam.   Next mods are a regrind, which I have sitting on the shelf, and a custom ITB manifold, as the stock intake manifold is very small and restrictive.

Edited October 20, 2016 by Mack

[clarkspeed]

Above, with bigger TB and ported manifold ahead of cam work.  I would rank the bowl work next, then mild cam, then more compression. 
Best to combine cam/compression/megasquirt in one project.

[Zetsaz]

This has been talked about like a billion times already even before the thread Tony and I hijacked from a griefer who wouldn't take advice. 

 

This thread goes into some tangents on turbos but good info nonetheless 

http://forums.hybridz.org/topic/123369-na-l28-performance-questions-efi-non-stroker/

 

BRAAP's guide is standard and what most people go to

http://forums.hybridz.org/topic/95316-braaps-l6-efi-induction-advice-and-tips/

 

 

Of course the best advice is to get your suspension and brakes properly sorted, and tune up your engine to proper oem specs

[Mack]

I rated the cam before the head work and throttle body, because you need the cam to take advantage of both of those. and swapping out a cam can be done without pulling the head.

 

 Porting the intake really won't do anything, at least on an EFI intake.  You can smooth it out, but to actually port it would be a huge pain in the ass and you may as well build a custom one at that point.  That being said, I did take the injector screw bumps out of the ends of mine as well as smooth out any bumps and ridges I could get to.  

 

if you want more compression, you'll need a different head or to severely modify yours.  at that point, all bets are off and you may as well do some porting, polishing and cam swapping "while you're in there".  You will end up with a few more than an additional 20 to 30 at that point.  

[clarkspeed]

Porting manifold means matching to larger TB in my previous post. I prefer not to touch the cam unless I raise compression, just personal preference for streetability and leaving the stock efi alone. Although I will say we got 200hp at wheels with 9:1 compression, huge cam, and aftermarket efi. Just not much fun to drive on street.

[Tony D]

My bone stock 330,000 mile L28E in a 76 Fairlady Z 2/2 with me in it weighing 2695# on the track's scale ran 15.50 all night long around 90mph... 26 passes at the San Antonio ZCON. Had a ratty crush-bent 2.5" exhaust at the time which likely was equivalent to the stock setup... The dyno said 147 hp, that 1/4 mile time  said something else. Oh, I did have a K&N filter in the stock box (I took off the CAI because it was  annoyingly loud for my driving...) Exhaust was quieter than stock, too! The EFI was the  CA Spec setup off the Bonneville car that had 176,000 miles on it when we stripped it off the car... 

I tuned it up to stock specs. There was a guy with a Silver stateside 76 Coupe with a Big Throat, CAI, Header and Exhaust and  I think an MSD 6 box in it along with a ton of chrome who was running 16.74 all night long, the last 13-14 passes directly against me to the point he was becoming foul and swearing at me.... I "had" to have put a cam in it because his blingwagen couldn't get better than  16,70 all night long.

American cars are way overgeared for what they do. People put all this emphasis on magic bullet bolt on crap and disregard  the tuning of the system. For the record, the  K&N Filter in the stock housing was as fast as it was  with the noisy CAI and cone filter on it! 

 

Exhaust. A Mandrel-Bent 3" is barely enough for a stock L24 to get optimal flow...yet everybody says 2.5" mandrel bent. Why? Because  it's easier to package. The  original TRUST exhaust for 2-liters and 2.4's was twin 50mm pipes... which is about 71mm flow capacity... 2.8" when they converted to a single pipe they universally went to 75mm pipe... coincidence? The stock manifold put to a 2.5,twin 50, or 3" pipe will have more HP than stock, with no issues on "the bottom end"...

For all this performance add-ons... anybody actually quantify them back-to-back on their car with a dyno or 1/4mile consistency check (a good example was Norm with the  SU's as he knew what his car ran, and could see  what mods did...)

As Zetsaz says, and I agree in this case if a swap is in order: Spend your money on the chassis and leave the engine alone. There's  no payback!

[hooahh3]

Well that spiraled quickly. lol

 

Yes ive decided to just go ahead and drop the 5.3 in it. Working on the parts acquiring for that right now. After everything it does just seem to be the best route for now and the future.

 

And that's what I was looking for more then anything Tony D. Some info from guys who have done the comparisons back to back of parts or mods. Not just thrown everything together and said this is what I got. Cause some things may be more "show then go" but theres no way of knowing unless its done systematically. One of the reasons I was hoping to get your opinion. You seem to have acutally done that or just messed with these enough over the years to have that already figured out, and be able to say whats the best route to go for the simple to wild from personal experience.

 

I also never really specified it but the full tune to specs was part of what I was planning. or basically your tuned 147hp + 20-30hp. so it would acutally be a true bump, not just trying to go around the way to get back to whats already there anyways.

 

But either way thanks for all the imput from everyone. If I didn't have the v8 already waiting, this would have defiantly helped me out and given me a lot better out come then just the way I was thinking of doing it.

[hooahh3]

In other news, anyone want or need an l28/4speed complete pull out? lol

 

Swap is well underway and hopefully done my next week home(if thanksgiving doesn't get in the way. So far it's gonna be well under a grand all said and done which is probably a 1/3? of what i would have spent for any where near 200 crank hp.