Chiselchst

First of all, thanks to all of the regular contributors in the HB threads. It has been a great source of help & info. I learned a lot, but I still don’t know squat.

I live in the People Republic of Kalifornia, so I’m restricted to CARB laws and 91 CAN gasoline.

The car is only used for street fun, no racing or track use. Reliability is primary. My goal is >550rwhp.

With just the HB installation alone, I should get ~500-520rwhp, right? That’s with the canned tune I assume. Would a “custom” tune help?

Correct me if I am wrong, but from what I have read here, due to CARB smogging regs the car must have:
1. Stock HB CARB blower pulley (96mm?)
2. Stock crank H/B sized pulley
3. No cam (per CARB)
4. No LT headers available (w/Cats)– shorties not worth $$$?

So Hypothetically?
a) If I swapped out the crank H/B with an OD one, might it be kinda difficult to detect?
b) I could *possibly* pulley down on the blower if it was “marked” correctly? Just asking…
c) METH? Trying to avoid METH though…


Per Old Motorhead (Thank you sir!) - If I could swap out the cam to a LS9 type, and swap exhaust manifolds to LS7’s how much HP might that add? Is it worth it? Is so, would it be worth the $$$ to go 3” on the exhaust system back to mufflers?

Thanks in advance!

lt1z

Yes the blower pulley is specified in the CARB cert

You could do meth and a lower and likely not be detected.

neverstop

could always just throw a 100 shot on it too and easily remove/hide the kit before smog time. I used to do that on lots of cars.

CI GS

Maybe you can buy a 90mm blower pulley and stamp the "0" over with a "6" and hope they don't use a caliper to measure it? JK!
Honestly though, from personal experience, after running the standard 96mm for a bit I changed to a 90mm, which is supposed to be good for another 30HP or so across the board. I could definitely feel the difference and boost now peaks at 8.4 psi, which I think is safe on pump gas.
IMV, the 90mm pulley is the perfect size for the HB to run safely on pump without meth and without changing the standard injectors.
That's what my friend Andy aka Streetk14 told me, and I think I've proven that to myself now.
Right now at WOT, my car is maxing out at ~94% IDC with the standard HB LS9 injectors, with an 11.4-11.7 AFR, 12.5-13 degrees of timing and zero KR on 92 octane.
However, if you think the smog cops are going to check the upper pulley size, it would probably be better to go with an OD HB. The only problem is that a IW or ATI will probably stick out like a sore thumb, so your best bet is a Powerbond 10% OD, which looks pretty much stock if your looking at it from up top, unless, of course, they notice that the main drive pulley is larger than the A/C pulley.
The added benefit is that it's much cheaper than either the ATI or IW and is SFI rated.

CI GS

BTW: With a stock HB (7.5") and a 90mm (3.54") the drive ratio is 2.11:1 and with the Powerbond OD HB (8.23") and your 96mm (3.77") the ratio would be 2.18:1, so with that HB you would probably see just a fraction more boost than I am seeing, with better belt wrap to boot.

Chiselchst

Thanks so much Sammy, that is exactly the kind of info I was looking for...

Question; If I installed the 90mm and had it tuned, could I then switch back to a 96mm (for Biennial smog check) without issue?

george536

They dont measure, but they look at stamping if it has any or if it doesnt look oem. A tech is just supposed to do it to the best of thei ability. Not just look away. So if your pulley says "x" and the pdf for the carb eo says "x" then its good.

So if you trick them, they'll be fine. They are not fluent in every single aftermarket part. Usully parts that are shiny or non oem looking are dead giveaways.

For exhaust, the z06 setup is a decent upgrade and gets through easy. Cams they wont know, no xray vision lol unless it has a crazy idle. And whoever tunes it just make sure monitors stay on for the plug in test. Good luck

CI GS

I think that's the easiest way to go, to be honest, because changing that Balancer would be a real PITA. Changing the pulley and belt twice a year is nothing compared to that.
The only reason I'm changing mine now is because I'm going to have to pull it off when I do the cam install anyhow.
I certainly think that you could drive it around with the 96mm after having it tuned for the 90mm, as that would only make a difference to your WOT tune anyhow. If you're only going to put it on to do the test, then you should be fine and even if you went WOT, it would probably just be a bit rich with less boost, IMV.
BTW: You'll need the 4060975 (or 6PK2475) Continental Elite Poly-V belt for the 90mm. Be warned though, it's very tight going on, so be prepared to do some cursing!

Unreal

How hard is it to swap the upper pulley? I can swap my ECS pulley in <10 minutes. Run a 87-90mm unless you need to go in, then put the 96mm on. If it takes <30 minutes then I think that would be well worth it.

CI GS

The pulley is dead easy. 4 bolts and you're done. But to get that 2475 belt on is a b!tch because it's a little on the short side but anything longer slips, apparently. I had to take the idler off and hold the tensioner down with one hand and slip the idler back on and then thread the bolt back in. Took me a while to get the damn bolt to thread in straight doing it that way. Maybe someone has a better way to do it, but that's the only way that worked for me.
It's probably nothing compared to changing the belt on an ECS system though?

schpenxel

I agree.. I'd just swap pullies if you need to come inspection time

ECS isn't too bad, it seems to depend on the combination of belt size/pulley size. With my 3.5" pulley and whatever size belt they recommend it was an absolute bastard to get on. I ended up removing the alternator bolts, got the belt on that, then took a pry bar and pried it back into place (while someone was holding the spring loaded tensioner fully open) and even then barely managed to get the alternator bolts in.

When I went to a 3.25" pulley and whatever size belt they recommend it was still a tight fit but went on without nearly as much hassle. I guess the belt/pulley combos yield slightly different amounts of slack.

Anyways. Enough about me.

Chiselchst

Thanks for feedback everyone, it's mucho appreciated.


The upper pulley/belt swap seems likes the ticket.


Anyone have any thoughts on if an LS9 type cam and Z06 exhaust manifolds would be worth the work? Would that make approx 35 HP?


Could I make my 550whp goal without these, using a 90mm pulley?


Thanks folks.

CI GS

The LS9 cam should be a decent option to gain some power if you wanted it to sound stock/avoid detection and make some more power.
Are there no CARB certified longtubes?
FYI: Andy (Streetk14) made 548whp on 91 CAN fuel with the same 90mm that I have on now, but with ARH 1 7/8" LTs.
Remind me, is your car an A6 or M6?

Chiselchst

Mine is M6. There are no LT's with the Cats (up tight/close to the head). From what I've read, the only "CARB" certified are short tube headers...

old motorhead

Yeah, a full Z06 exhaust would be a nice upgrade. It's 3" all the way back to the mufflers. Get the whole thing. It will bolt on and look totally stock. That, and the LS9 cam should help you hit your numbers.

Your inspector would have to have a damn sharp eye to notice the difference between a 96 and 90mm pulley on the blower. That's less than a quarter inch difference in diameter (eighth inch less on either side). Plus, if I remember correctly, the pulley numbers are on the back side of the pulley. Even if he knew what it was supposed to have, it's going to be tough to see. I wouldn't worry about it. Hell, if he spots it, go home, put your original belt and pulley back on, and take it to a different inspector.

Chiselchst

That's music to my ears! That's kinda what I was hoping, but it sure helps with input from guys like you with your experience... Thanks

Would that cam require any valve train upgrades like springs/retainers? I've got all of the specs in my records, but not sure of the limits of the stock heads & springs.

And I'm going to A$$ume a dashlogic, with the ZR1 MAP sensor would also be very desirable?

Thanks everyone appreciate your help!

schpenxel

ZR1 MAP and dash logic is a lot of win in my book

Just make sure whoever is doing the tune knows what MAP sensor you are using.

old motorhead

LS3 valve springs are the same ones used in LS9's. You rarely hear of these springs having or causing problems. I believe stock LS9's are well over 10psi. No reason they won't work for you at milder boost. I would respect the 6500 rpm red line though. Really no reason to rev an LS3 to the moon when you have a TVS on top. After you shift at a little over 6000 rpm, your tq actually goes up. Boost will be the same after shift as before. May be a tad higher after the shift. So, no great advantage with 6500+ rpm engine speeds. Your engine will love you long time with 6K rpm shifts.

Chiselchst

OK, roger that - thanks. Can't express my appreciation for the depth of knowledge here - mucho appreciated.

One more question if I may? 2013 ZR1 exhaust mani's and 3" back to axle will fit on my LS3, right?

Are the Z06 & ZR1 exhaust systems the same?

Thanks!
I getting hooked up with a local on this forum for the install & tune. Great rep here...

schpenxel

Yep, Z06 or ZR1 system will fit an LS3. I have them on my LS2.

ZR1 system uses an X pipe, Z06 uses an H pipe. I'm about 90% sure the cats and headers are exactly the same

My old LS2 parts looked like toys sitting beside Z06 parts

I'm thinking about selling my cats/manifolds/H pipe and going with long tubes. I hadn't even thought about selling them, but I might be selling some soon if you want them

edit: just saw you're in CA. Yeah shipping probably wouldn't work out so well!