WREK LS1

To the CA folks, has anyone attempted a 100% smog-legal build on their
LS1? No corner cutting or cheating, I mean a real honest to goodness build that will pass CA emissions testing with flying colors and make better then average power. Can it be done and if so, how? (Please don't suggest N20).

I know i could "pay a guy", but I'd rather not go that route. Car is a 98 Z M6with a lid and catback.

Wheelman916

CARB legal supercharger kit. CARB legal AFR heads. CARB legal Fast 102 intake manifold. Very mild cam. CARB legal shorty headers. Very high flow cat back.

A CARB legal blown H/C/I LS1 should make better than average power without a problem.

WREK LS1

Good suggestions. I thought a ported LS1 intake and ported stock heads were the only alternatives. I'm guessing the cam would have to be very mild.

1Psycho

iTrader: (9)

doesn't have to be a very mild cam to pass and there's a few other things you can get away with like ls7 manifolds (will make bettwe power than ls1 shorty headers)

Empatho

iTrader: (16)

Do ls7 manifolds fit a 4th gen? what about the cats?

WREK LS1

I was wondering the same thing since the cats have to remain in exactly the same position as from the factory.

ryridesmotox

Toss a Maggie on there. I'm pretty sure its smog legal.

Empatho

iTrader: (16)

I seen it done on a c5 but never on a 4th gen fbody.

1moreamp

Depending on what your looking for just get a GM crate CARB approved motor and drop it in. That will cover you up to 600 HP depending on which CARB approved crate motor you buy.
Depending on how much of a dick your smog guy is what will decide if the thing has to go to referee or not. If so get it reffed, and get the tag and then don't worry about it.

I replaced a stock in line 6 cylinder in a four wheel drive 20 years ago with a bone stock V8, It had to get reffed and for a few years it had to get smogged every year because Cali just wants you to. But I don't live in the bay area no more so its a tad bit easier when you leave the two big city hub areas.
Hell where i live they don't apply vehicle height laws, headlight laws, tire outside wheel well laws, etc... Its better if you don't try to live in the LA basin and the Sf bay area where Smog tends to be a voting issue.
We got fast and furious types out here right and left and no one seems to be making any of them abide by any laws, like hoods being taken off for street cruising, etc... But then again laws only apply to a few in Cali and only on certain days of the year LOL LOL LOL...



there is a guy on C list trying to sell his maggie setup right now , It was in a pickup truck lol,



.

98MysticGreen

Theirs always plan B. Move to Arizona and not have to worry about ****

5 years cali is gonna out law anything bigger then a v6 LOL

1Psycho

iTrader: (9)

Technically they do but to pass they don't necessarily have to be..if a cat goes bad the "smog legal" replacement isn't gonna be in exactly the same spot. Only downfall with ls7 is the egr tubes

Been done, very uncommon though

More expensive but you can buy a smog legal LS3 or LSA swap..

99Bluz28

iTrader: (35)

IMo, best bang-for-the-buck!

With your 98 I'd find a SLP LS6 intake manifold w/egr. I'd also have the factory heads CNC ported and milled to get the SCR up to 11.0:1, have the passenger side y-pipe before the cat removed and replaced with a thicker single wall tube since the factory double wall tube is the biggest restriction on the factory y-pipe. Follow that with replacing the factory merger with a Magnaflow #10778 Y-pipe merger for better flow. Back to the engine cam, 222/230 117lsa+5 w/LXL/XE lobes an a IVC of 43 an -8* overlap, or a 218/226 115lsa+4 w/LXL/XE lobes with a IVC of 40 an -8* overlap, and option 3 a 220/228 116lsa+4 w/XE/XE lobes and a IVC of 42 an -8* overlap. This is roughly what you want to look at as far as cams. They'll all be within about 200 rpm as far as peak power, have a very mild cam sound, fairly quiet valve train, and will pass smog easily with a good tune. Regardless of your cam choice stick with about a 8* I/E split, and the 222 would be the largest I'd go with the intake duration without sacrificing some lower rpm power for top-end when using a 117 or wider lsa. As far as supporting modifications just follow what's done with any other cam swap.

WREK LS1

Excellent info, thanks! What would you guesstimate that combination would put down on a chassis dyno?

Empatho

iTrader: (16)

There is a thread on the corvette forum of some guy that got egr tubes welded on the ls7 manifolds, looked like a well done set up. Do you have any pics of the ls7 manifolds and cats on an fbody?

1Psycho

iTrader: (9)

Don't have any pictures yet..have a customer that wants to do it for the stealth look but won't be in for a couple weeks

99Bluz28

iTrader: (35)

I would say 400rwhp is possible.
I'd have the factory head ported by AI if possible,or you could go with a set of CARB approved aftermarket heads like the AFR 210 or 215 cc heads. FYI I forgot a 4th option on cams, a 222/230 116lsa+5, IVC is 42 and -6* overlap, otherwise same cam lobes a the 222/230 with the 117lsa. IMO, even though I used Comp Cam lobe in these examples, I'd also recommend looking at Cam Motion cams since their lobes are available in a wider range of lifts and in 1* size intervals, along with tighter tolerances in lobe size variation, and the softer ramp rates will offer longer valvetrain life and better high rpm stability that the Comp Cam XE an LXL lobes I listed.
http://www.cammotion.com/index.php

99Bluz28

iTrader: (35)

FYI, LS7 exhaust manifolds will fail a visual inspection, even if you can get them modified to fit properly in a F-body engine compartment. Yeah, they'll flow better, but L.T. header will flow the best and net the same results; a failed visual inspection. I'd recommend he stick with either the stock exhaust manifolds or CARB legal shorty headers, which will totally avoid any possible legal hassle he doesn't want.

Wheelman916

I think a used supercharger kit would be better bang-for-the-buck.

You can buy a used supercharger head unit that has the CARB EO# plate, in need of a rebuild... send it off for rebuild... then cobble together the rest of the kit from used pieces or cheap replacements from a place like superchargersonline.com or others sites. There is a thread floating around the internet for almost a decade, breaking down a budget supercharger build for a 2v Mustang that was under $1500.

Or you can buy a complete used supercharger kit.

Either way, expect over 400rwhp at 6psi, with plenty of room to grow with additional modifications and boost.

Empatho

iTrader: (16)

Nice, post some pics when you can.

CaliboyTA

iTrader: (2)

procharger p1sc