raidersforever01

After wallowing in my regret and shame for selling my camaro for the last 3 years. I got an 07 vette M6 and because i can never leave well enough alone decided i wanted more but since road side smogs like to pop up randomly in my area still needed to pass smog so just got myself a Fast 102, ported 799 heads, and a TSP 224R 112 LSA. My buddy started tearing down the car for me and immediately we saw the previous owner was an ahole and put a bunch of unknown crap on the snout of the crank to get it by to offload it. After getting it off it looks like he must have drove it around with a wobble before that because its ruined. So now i am saying screw it lets pull it out and see how much power we can get out of it and pass the sniffer. With such a small cam necessary to pass smog is it even worth stroking it?

RB04Av

Of course you should STROKE IT.

Oh, your motor... sorry, well, that's a deeper question...

Seriously, if ya gotta buy a crank, MIGHT AS WELL stroke it. OTOH that requires adjustments to the pistons and/or rods. If you're not disturbing any of that, then you can't really change the stroke either, since the sum of the piston compression height (made into it at the time of production) plus the rod length plus half the stroke, has to equal the block's distance from the crank CL to the deck, give or take acoupla .001"s. So, if you're leaving the pistons in the block, NO you cannot stroke it. (not the motor, that is) if you're buying pistons AND a crank ANYWAY, it's a no-brainer.

grubinski

I'm not a Corvette guy, so not sure ... is this an LS3 or an LS2? What kind of ported heads?

In general, if you have the same heads and cam on two different sized engines, the smaller displacement one will rev higher and have a wider powerband. So stroking it will restrict your powerband a bit.

BUT ... Since you're using a stock style plastic intake, that will restrict your powerband a bit on the top end even on the smaller engine ... so you could make an argument that for a street car, the bigger stroke means more torque everywhere, and you only giving up the 500 rpm between 6200 and 6700 (to use two random, but fairly close numbers).

If it was my car/money, I'd just leave it at stock displacement. Maybe put on an underdrive pulley, make sure the exhaust is really good, etc. if you have money burning a hole in your pocket.

KW Baraka

iTrader: (7)

LS3 was first offered by GM in 2008.

KW

raidersforever01

Nothing wrong with stroking a motor or other things as well.

I assumed i would have to change out pistons as when i ran numbers i saw compression would go through the roof but ill need a little help figuring out how to calculate that. Should i just get a forged kit. I am assuming everything would be picked out to work. I wanted to use some cometic .041 gaskets for the quench also. Would someone know of a calculator i can punch in the these numbers to see what would work.

Baraka is correct it is an ls2 the heads are ported 799's from wilkes performance. Since the OE one is screwed anyway i was going to put on an underdrive also i use it as my daily so losing some up top for torque sounds like a fun street car which i prefer.

I may be off base after doing my camaro i kinda fell off the car scene and havent kept up with stuff. Would the added cubes allow me to go a little bigger with the cam and still pass a sniffer?

grubinski

I think you still want the 0 overlap of the cam you have to pass a sniffer, but you could add some duration away from the overlap region ... later IVC, earlier EVO events. The larger stroke will also raise your compression ratio, which will mean you will benefit from both of these changes.

raidersforever01

Anything in mind you had? I got the TSP dualspring kit with the 224r. ill probably just sell the cam and keep everything else from it.

grubinski

I'm not a cam expert, you need Darth_V8R or one of the other gurus on here to suggest something. Or have Pat G spec you one custom.

Given that, I'll hazard the guess(es) below, and see how far off it winds up...

TSP has the 228R, on a 114 LSA that's 0 overlap. I'm not sure what advance it's ground on, if any. Also not sure what a 402 (LS2 at 4" stroke IIRC) likes as far as IVC timing, but the bigger the engine gets, the later IVC they tend to like. If the 228R is ground at 114+0, that just might work for a 402, with IVC at 48 ABDC. You'd probably want around 11.5:1 for compression with an IVC event that late so your dynamic compression is high enough to keep the engine feeling snappy. Given a 228/228 114+0, it would open the exhaust valve at 48 BBDC ... which may be later than you want. At that point, you start looking for something besides the TSP228R, say 228/232 115+1, which would have the same events at TDC exhaust giving 0 overlap, 48 ABDC IVC, and 52 BBDC for EVO.

Nothing is as fun as bench racing cams, however, I am not an expert.

raidersforever01

I am glad you said that as i was thinking of 228/232 aswell so at least i know my thinking is in the right direction but yeah i am no expert. Hopefully we can get one of the guru's to suggest something or maybe i will have Pat g spec something out a custom one is starting to sound enticing.

spanks13

iTrader: (5)

So, prepare for everyone to talk **** on your build because you have a "built engine" that should be making way more power according to the internet, but there's serious performance there. I would 100% recommend it for CA. I'm also in CA and have put 20k miles on my 402 with LS3 heads cruising next to cops and in traffic. The stealth factor has definitely helped me out living here I feel like. I ruined that stealthiness by putting a 242/250 cam in it because I was bored during quarantine lol.

I had a custom spec'ed 0 overlap cam in my engine. 226/242 on 117+3.5. 11.1:1 compression running 91 octane. Most recently it made 512/509 at the wheels. This is factory ls3 heads no porting, ls3 rod mod intake, 1 7/8" headers into dual 2.5". Nothing crazy.

For cathedral heads, if you get up to 11.5:1 compression, I'd recommend 232/236 on 117+3.

https://cammotion.com/camshafts/stea...athedral-port/

Or just buy this off the shelf - they both should work for you.

0 overlap doesn't mean no overlap - there's still overlap the entire time it is below .050" lift so don't get too hung up on 2.5 degree overlap at .050".

Also FYI - you can decline testing at any of those roadside smog places. It is "for our benefit" not a mandatory smog trap. During actual emissions testing I don't think they tailpipe newer vehicles anymore.

raidersforever01

It's the internet. The internet is always right lol. Can you really decline to get tested? I havent been caught in one yet but a couple buddies got their cars forced into it and impounded. Maybe it was just the the cops being hard asses and scaring them into doing it knowing what they had but those guys had obvious cams in them. Thats why i liked the xfi 466 in my camaro it made decent power and you didnt know the car was cammed so never got hassled.

grubinski

Except when it's *known* that 0 overlap (@ .050") will pass a sniffer, and that's what he needs to do, why should he risk it? 0 degrees will idle smoother in a street car anyway.

spanks13

iTrader: (5)

You're right in that the bigger you go the more risk there is with passing smog, but the rule of thumb I believe has crept up slightly over the years. Just pointing out that 0 degrees at .050" lift does not mean that there will be no extra emissions coming out the exhaust and 2.5 degrees will have a ton of unburnt fuel. They both will have much more emissions than a stock cam, and 2.5 degrees will be marginally more than 0 degrees.

Bspeck82

I'd look into a solid. More performance and better idle quality vs hydraulic counterpart given similar durations at .050. Call cam motion.

grubinski

That's an IVC timing of 50 degrees ABDC ... is that what a 402 likes? I know stock displacement LS3s are supposedly happy around 47 degrees or so, and bigger engines are happy later. Not clear on exactly how much the variance is. What does a 408/416/427 like for IVC? Any idea?

bortous

An IVC of 50 is about right for a 408.
It's what I had in mine.
It also depends on how far you want to rev out too.
This can change the requirement.
A 427 would require an IVC 2 degrees later for the same effect.

raidersforever01

Hmmm... just sitting here taking notes finding out just how little i actually know lol.

I don't plan to rev it to the moon. I am fan of how it feels when driving in town. I like to get groceries in the funnest way possible.

spanks13

iTrader: (5)

https://www.yellowbullet.com/threads...design.410450/

You can do a lot worse than following Brian Tooley's info on the bullet. There are some more threads where he is spec'ing cams for people and sharing his thought process if you search. This one has been in my bookmarks for a long time and I reference it every once in a while.

In my mind for pretty average street stuff - stock stroke engines IVC 44-48*, 4" stroke engines 48-52*, big cube or drag race stuff 52*+

spanks13

iTrader: (5)

I want to build a street engine someday with a mild lift low lash solid roller ~.675", BSR shaft rockers and XD-A pushrods from comp. Super light weight valvetrain and no lash adjustment through the life of the engine.

Bspeck82

im building one rn for a sbc 400. Learning what I have learned about it I would've done so for the ls. Not like I put lots of miles on it anyways. Check lash once a month which is easy on the 400 and good to g . Better lobes offering great mid lift performance and high rpm power as well as better idle quality needing less overlap to make the same power.