Pulley question!? - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

BigBlock427 · 05-07-2016, 04:03 PM

So...

My plan is to order a 10" lower (w/belt), 160 thermostat, and a solid supercharger isolator.

I currently have:
Dynatech 2" Header w/ no cats
C.A.I. Intake

the tuning will be done by JRE.

the lower pulley should produce 14lbs of boost. But since I have 2" headers and no cats I doubt ill hit that. Could I do a 2.5 upper down the road? or will I be spinning to fast at that point? with the 2.5 upper and a 10" lower combo should hit 18lbs... but again with the headers I dont think ill hit that. obviously at this time I would invest in injectors and a boost-a-pump.

BUT...

Dynatech 2" Header w/ no cats
C.A.I. Intake
10.00" Diameter Crank Pulley
160 thermostat
solid supercharger isolator
JRE tune

Should I be investing in fuel now? or can I wait? If I need fuel ill just wait and doing everything at once. Please let me know if I should be adding anything.

ttshovel · 05-07-2016, 04:30 PM

I have the ls3 bottom end so my boost level might be impacted by that. I have a 2.5/9.55 combo. It makes 19psi. I also have 2 inch headers, btr stage 3 pd cam and ported heads, ported snout, and a nw 102tb. Pretty much everything that would/could lower boost...

Just something to think about.

I wouldn't be as concerned about the psi number as much as blower speed. The 9.55/2.5 combo is spinning it very hard at my 6600 shift point. So if you went with a 10/2.5, you could just lower your shift point to not over spin the blower.

BigBlock427 · 05-07-2016, 04:41 PM

Yea thats what I was thinking. So Maybe I should go with a smaller lower to plan for the future. Or just go with the 10" till I feel the need to make more boost and just switch it out with the new upper to what ever ratio I decide to go with.

With only the 10" do I need to worry about fuel yet? Or should I hold off? I am assuming having the extra fuel on stand by could do nothing but help?

JohnnyC · 05-07-2016, 04:49 PM

Pretty sure if your over 10% JRE wont tune without injectors

BigBlock427 · 05-07-2016, 04:59 PM

yup that is what I am finding out now...

go with the the 8.8" from the 75rwhp kit. Then do the 2.5 upper and the injectors with the BAP down the road. that should hit 14-15lbs and keep the spinning in a safer zone.

m1key1111 · 05-07-2016, 07:47 PM

If you're doing a solid isolater which requires you to remove the snout you can just do a 2.50 upper pulley (since you'll have the snout off anyways) and it'll produce 14/15 psi with a stock lower pulley.

Then down the road add the lower.

ZL1Kid_AL · 05-08-2016, 02:42 PM

Quote:

Originally Posted by BigBlock427

So...

My plan is to order a 10" lower (w/belt), 160 thermostat, and a solid supercharger isolator.

the lower pulley should produce 14lbs of boost. But since I have 2" headers and no cats I doubt ill hit that. Could I do a 2.5 upper down the road? or will I be spinning to fast at that point? with the 2.5 upper and a 10" lower combo should hit 18lbs... but again with the headers I dont think ill hit that. obviously at this time I would invest in injectors and a boost-a-pump.

I have a 10in metco lower and correct belt for stock upper+10 combo for sale. 2400miles on them. I'd sell for way cheaper than buying new. Shoot me a PM if interested
But..

2.5 and 10 lower will be severely over spinning the blower. It would be heat soaked all the time, unless you had every cooling mod possible.. Even then that's not enough IMO

*mlee* · 05-08-2016, 03:01 PM

If you are doing the solid isolator be sure and put a hub on so you can easily change the upper pulley. (Actually I don't know why you wouldn't just put the 2.55 on since the S/C will be off anyway and the hub would require a new pulley)

Injectors will also need to be changed with any Header/Pulley combo.

The 10 and 2.55 might be a over spinning and you would need the idler re-locator as well.
I have the Metco lower with an 8.6 and 9.1 interchangeable rings and 2.55 upper. The 9.1 lower requires the relocator.

Name: LPE.JPG
Views: 581
Size: 183.4 KB

evonschu · 05-09-2016, 01:35 PM

I'd try the lower pulley alone first. I read around on here many people saying oh it'd be 14lbs and saw LPE charts saying it'd be about the same as the 8.66 + 2.55 upper / lower combo a lot of peeps do. However it was higher than expected and I had 16lbs at max RPM even with kooks 1 7/8" headers. Borderline needed to get meth inj with that much boost. Might be different for others, but that's what I experienced. I had a ported 87mm CMAX TB and Rotofab CAI too.

tabio42 · 05-09-2016, 02:15 PM

Anything over a 9" lower will probably need injectors unless you use supplemental fuel like methanol. But then you are relying on the meth for fuel so that's not the safest route.

If you go 10" lower, the most you can do is a 2.85 upper in the future. Anything more and your pulley ratio puts the supercharger speed in unsafe territory.

So you will still have room to grow in the future of you need it, but how fast you can spin the blower depends on how well you can cool your IAT2. I would suggest investing in an aftermarket HX as well.

05-07-2016, 04:03 PM	#1
BigBlock427 ConceptZer0 Drives: 68 427 Camaro, 11 2SS/RS, 13 ZL1 Join Date: Jul 2010 Location: nj Posts: 1,096	Pulley question!? So... My plan is to order a 10" lower (w/belt), 160 thermostat, and a solid supercharger isolator. I currently have: Dynatech 2" Header w/ no cats C.A.I. Intake the tuning will be done by JRE. the lower pulley should produce 14lbs of boost. But since I have 2" headers and no cats I doubt ill hit that. Could I do a 2.5 upper down the road? or will I be spinning to fast at that point? with the 2.5 upper and a 10" lower combo should hit 18lbs... but again with the headers I dont think ill hit that. obviously at this time I would invest in injectors and a boost-a-pump. BUT... Dynatech 2" Header w/ no cats C.A.I. Intake 10.00" Diameter Crank Pulley 160 thermostat solid supercharger isolator JRE tune Should I be investing in fuel now? or can I wait? If I need fuel ill just wait and doing everything at once. Please let me know if I should be adding anything.

05-07-2016, 04:30 PM	#2
ttshovel Drives: 12 camaro ss, 72 chevelle, 91camaro Join Date: Dec 2013 Location: findlay,oh Posts: 2,069	I have the ls3 bottom end so my boost level might be impacted by that. I have a 2.5/9.55 combo. It makes 19psi. I also have 2 inch headers, btr stage 3 pd cam and ported heads, ported snout, and a nw 102tb. Pretty much everything that would/could lower boost... Just something to think about. I wouldn't be as concerned about the psi number as much as blower speed. The 9.55/2.5 combo is spinning it very hard at my 6600 shift point. So if you went with a 10/2.5, you could just lower your shift point to not over spin the blower. __________________ 12 camaro ss 427lsx, th400, f310 heads, crower shaft mounts, gpi specd solid roller, shearerfab 2k hp a/w, twin bullseye 88mm turbos, hughes pro ssx bolt together converter, holley dominator, 8.50 cert, backhalf, Ford 9", 33x17x16 tires, c16 fuel

05-07-2016, 04:49 PM	#4
JohnnyC PURBRED Drives: 2014 Camaro ZL1, 2007 Gmc Duramax Join Date: Dec 2013 Location: Sherwood Park Alberta Posts: 279	Pretty sure if your over 10% JRE wont tune without injectors __________________

05-07-2016, 04:59 PM	#5
BigBlock427 ConceptZer0 Drives: 68 427 Camaro, 11 2SS/RS, 13 ZL1 Join Date: Jul 2010 Location: nj Posts: 1,096	yup that is what I am finding out now... go with the the 8.8" from the 75rwhp kit. Then do the 2.5 upper and the injectors with the BAP down the road. that should hit 14-15lbs and keep the spinning in a safer zone. Last edited by BigBlock427; 05-07-2016 at 05:24 PM.

05-08-2016, 03:01 PM	#8
mlee CamaroFans.com Drives: ZLE & ZR2 Join Date: Oct 2008 Location: Conroe, TX Posts: 37,497 View My Garage	If you are doing the solid isolator be sure and put a hub on so you can easily change the upper pulley. (Actually I don't know why you wouldn't just put the 2.55 on since the S/C will be off anyway and the hub would require a new pulley) Injectors will also need to be changed with any Header/Pulley combo. The 10 and 2.55 might be a over spinning and you would need the idler re-locator as well. I have the Metco lower with an 8.6 and 9.1 interchangeable rings and 2.55 upper. The 9.1 lower requires the relocator. __________________

05-07-2016, 04:41 PM	#3
BigBlock427 ConceptZer0 Drives: 68 427 Camaro, 11 2SS/RS, 13 ZL1 Join Date: Jul 2010 Location: nj Posts: 1,096	Yea thats what I was thinking. So Maybe I should go with a smaller lower to plan for the future. Or just go with the 10" till I feel the need to make more boost and just switch it out with the new upper to what ever ratio I decide to go with. With only the 10" do I need to worry about fuel yet? Or should I hold off? I am assuming having the extra fuel on stand by could do nothing but help?

05-07-2016, 07:47 PM	#6
m1key1111 Drives: 2012 ZL1 Join Date: Nov 2015 Location: Atlanta GA Posts: 88	If you're doing a solid isolater which requires you to remove the snout you can just do a 2.50 upper pulley (since you'll have the snout off anyways) and it'll produce 14/15 psi with a stock lower pulley. Then down the road add the lower.

05-09-2016, 01:35 PM	#9
evonschu Drives: Camaro ZL1 Join Date: Oct 2012 Location: Hillsboro, OR. Posts: 166 View My Garage	I'd try the lower pulley alone first. I read around on here many people saying oh it'd be 14lbs and saw LPE charts saying it'd be about the same as the 8.66 + 2.55 upper / lower combo a lot of peeps do. However it was higher than expected and I had 16lbs at max RPM even with kooks 1 7/8" headers. Borderline needed to get meth inj with that much boost. Might be different for others, but that's what I experienced. I had a ported 87mm CMAX TB and Rotofab CAI too.

05-09-2016, 02:15 PM	#10
tabio42 Drives: CTS-V Join Date: Mar 2013 Location: Orange County, CA Posts: 43	Anything over a 9" lower will probably need injectors unless you use supplemental fuel like methanol. But then you are relying on the meth for fuel so that's not the safest route. If you go 10" lower, the most you can do is a 2.85 upper in the future. Anything more and your pulley ratio puts the supercharger speed in unsafe territory. So you will still have room to grow in the future of you need it, but how fast you can spin the blower depends on how well you can cool your IAT2. I would suggest investing in an aftermarket HX as well.