ZL1 Pulley & Tune Projected HP/TQ?

[leviticus88]

Originally Posted by hognutz

I think you can go up about 3psi without changing much. headers and intake are not hard.

So I mean pumping the car up to 625-650bhp should not be hard or too expensive and could probbbaly be done with exhaust intake or pulley and tune.

I read some posts on CTS-v forums adding longtubes and pulley sometimes people did not end up with the same boost numbers as without.

^^^^This is a good thing and a sign that the modifications worked and improved airflow.

Originally Posted by ZL WON

When you open up the exhaust, as in adding headers or free flow exhaust, you loose boost. That's why people with CTS-Vs and ZR1s are loosing power. You have to compensate by changing out the pulleys. What I typically see when I modify ZR1s or any other supercharged build I do, I see at the most a 2lb loss in boost by adding headers and exhaust. If this is done to the ZL1 that will put the car at 8lbs of boost. I run my ZR1 at 16lbs. Anything over that, you'll have to run race gas. On my Escalade and Denali GMC truck I run 10lbs of boost and use the LS9 camshaft. My plan for my ZL1 is to mimic what I did for my ZR1, which is CNC'd heads, cam, upper and lower pulley, headers, upgraded after cooler and heat exchanger, upgraded supercharger coolant pump, one stage colder spark plugs and a few other tricks. I'll also add a 10-rib belt conversion to the ZL1 as well to prevent any belt slippage. I'll have all this done in about two weeks after receiving the car, as soon as we get our baseline RWHP number. I'll put the entire build on Camaro5.

^^^^Why would they be losing power with lower PSI numbers on the Same Pulley? This makes no sense.

Boost is not a measure of Horsepower. Freeing up airflow in and out of the engine will reduce the amount of pressure (Boost PSI) but increase the amount of CFM and cause an INCREASE in HP and Torque. Loosing PSI is not a bad thing when you are freeing up intake and especially exhaust flow.

For example, My experience:
2 identical cars:
One has everything stock and 12 PSI making 215whp.
The other has exhaust and intake modifications and tuning for them, but still on the same stock pulley making only 10 PSI and 230whp.
The lower PSI car has MORE POWER than the Higher PSI.
Now Compensate by adding a Smaller Pulley and returning the PSI to 12 results in 245whp.

Boost PSI is a measure of restriction only, the true measure you want is CFM in and out of the engine. An engine is an air pump and increased efficiency in and out results in lower restriction and pressure, but more performance.

[ZL WON]

Originally Posted by leviticus88

Why would they be losing power with lower PSI numbers on the Same Pulley? This makes no sense.

Boost is not a measure of Horsepower. Freeing up airflow in and out of the engine will reduce the amount of pressure (Boost PSI) but increase the amount of CFM and cause an INCREASE in HP and Torque. Loosing PSI is not a bad thing when you are freeing up intake and especially exhaust flow.

For example, My experience:
2 identical cars:
One has everything stock and 12 PSI making 215whp.
The other has exhaust and intake modifications and tuning for them, but still on the same stock pulley making only 10 PSI and 230whp.
The lower PSI car has MORE POWER than the Higher PSI.
Now Compensate by adding a Smaller Pulley and returning the PSI to 12 results in 245whp.

Boost PSI is a measure of restriction only, the true measure you want is CFM in and out of the engine. An engine is an air pump and increased efficiency in and out results in lower restriction and pressure, but more performance.

I deal with this on a daily basis. I modify a lot of ZR1s and CTS-Vs. Experience just shows this just happens. This is why a lot of ZR1 guys were complaining when they threw on a set of headers and retuned it, they were making less HP than factory. The solution is to put on a smaller pulley to bring the PSI up to compensate for the loss of 2lbs. The car responded very well to this with better than factory numbers. I see the same for the CTS-Vs and any other supercharged cars I build.

And what car are you talking about that makes 12lbs of boost and only makes 215WHP? Is that a Briggs and Stratton riding mower?

[Rice Killer]

Originally Posted by ZL WON

And what car are you talking about that makes 12lbs of boost and only makes 215WHP? Is that a Briggs and Stratton riding mower?

Gotta get me one of those!

[BigHemiSrt]

Originally Posted by leviticus88

^^^^This is a good thing and a sign that the modifications worked and improved airflow.



^^^^Why would they be losing power with lower PSI numbers on the Same Pulley? This makes no sense.

Boost is not a measure of Horsepower. Freeing up airflow in and out of the engine will reduce the amount of pressure (Boost PSI) but increase the amount of CFM and cause an INCREASE in HP and Torque. Loosing PSI is not a bad thing when you are freeing up intake and especially exhaust flow.

For example, My experience:
2 identical cars:
One has everything stock and 12 PSI making 215whp.
The other has exhaust and intake modifications and tuning for them, but still on the same stock pulley making only 10 PSI and 230whp.
The lower PSI car has MORE POWER than the Higher PSI.
Now Compensate by adding a Smaller Pulley and returning the PSI to 12 results in 245whp.

Boost PSI is a measure of restriction only, the true measure you want is CFM in and out of the engine. An engine is an air pump and increased efficiency in and out results in lower restriction and pressure, but more performance.

This is how it should work. I dont know whats going on with these cars losing power. Laws of physics says it shouldnt be happening.

[mlee]

Originally Posted by BigHemiSrt

This is how it should work. I dont know whats going on with these cars losing power. Laws of physics says it shouldnt be happening.

There's more to the physics than flow in/out... backpressure is an integral part of the equation too...

[2011RS/SS]

I made a 100rwhp increase in my V with a 9.5 lower, stock manifolds but with 3 inch piping from the cats back, and a CAI.

I got friends making 200rwhp over stock with no problems. Its all in the tune to keep it living

[ADM PERFORMANCE]

Originally Posted by 2012ZL1

How much will the stock bottom end take safely before it becomes a problem?

Depends on the fuel.So far no LSA failures from our shop,and we push the envelope.

[ADM PERFORMANCE]

Originally Posted by mlee

Is belt slip an issue with ctsv and this pulley?

Not an issue with correct length belt.

[ADM PERFORMANCE]

So we finished another Stage 3 package on a 2011 CTSV Wagon Auto and the results are strong.

The car was highest stock we have ever seen,But the customer told us he runs Torco a bit often...Base dyno showed very good timing with 0 knock....Normally see a few degrees on stock cars and 93 octane causing lower dyno numbers.

So here is the results-



PM for price of this upgrade.ZL1 Should be within a few hundred of the CTSV.

[radz28]

It seems to me adding free-flowing exhaust should lower boost for the same reasons as another person has already pointed out. As far as why ZR1s are losing power - that could be because I just recently read those stainless manifolds can actually make more power than some LTs (I read that in an artcile in GMHTP I think - that was a quote from SAM, or another shop I believe).

Andy - do you have some 'V info' on your site, or will you be adding ZL1 parts to your catalogue? Thanks

[ADM PERFORMANCE]

Originally Posted by radz28

It seems to me adding free-flowing exhaust should lower boost for the same reasons as another person has already pointed out. As far as why ZR1s are losing power - that could be because I just recently read those stainless manifolds can actually make more power than some LTs (I read that in an artcile in GMHTP I think - that was a quote from SAM, or another shop I believe).

Andy - do you have some 'V info' on your site, or will you be adding ZL1 parts to your catalogue? Thanks

New website coming soon!!!

[Hennessey Performance]

Here is my daily driver, LSA-powered station wagon running on street tires with full tire pressure:



Mods include heads, cam, headers, intake, injectors, crank pulley and tune which result in 642 rw hp thru the factory auto. Given the fact that my wagon weighs several hundred pounds more, the new ZL1 should be a very low 11 on street tires and deep into the 10's on a drag radial.

Lots of good times to come when the ZL1's hit next year!

[Hennessey Performance]

Sorry I missed the point of this thread as being "pulley and tune" question. We've upgraded several hundred LSA-powered CTS-V over the past 3 years and here is what I know.

1. A stock V with 6-speed manual will make around 490 rw hp. Thus I will guess that the ZL1 will make 520-525 rw hp thru it's manual trans.

2. Depending on the pulley change, adding 2-3 psi of boost with a 93 octane re-tune is worth 40-50 rw hp.

3. A less restrictive cold air induction will add another 10-15 rw hp.

4. Header and / or exhaust mods will give a nominal gain in power, but not as much as you might think. I would suggest doing headers and leaving the factory rear section exhaust alone. We do this on most of our CTS-V's and Corvettes as well as our Camaro supercharger packages and they all make great power thru the factory rear section exhaust. Expect around 20 rw hp with the headers.

5. The above listed mods added to a stock V will take the power from 490 rw hp to around 570 rw hp, a total gain of 80 rw hp and about the same gain in rw torque.

6. The same mods should equal close to 600 rw hp on the new ZL1.

[htron50]

Originally Posted by Hennessey Performance

Sorry I missed the point of this thread as being "pulley and tune" question. We've upgraded several hundred LSA-powered CTS-V over the past 3 years and here is what I know.

1. A stock V with 6-speed manual will make around 490 rw hp. Thus I will guess that the ZL1 will make 520-525 rw hp thru it's manual trans.

2. Depending on the pulley change, adding 2-3 psi of boost with a 93 octane re-tune is worth 40-50 rw hp.

3. A less restrictive cold air induction will add another 10-15 rw hp.

4. Header and / or exhaust mods will give a nominal gain in power, but not as much as you might think. I would suggest doing headers and leaving the factory rear section exhaust alone. We do this on most of our CTS-V's and Corvettes as well as our Camaro supercharger packages and they all make great power thru the factory rear section exhaust. Expect around 20 rw hp with the headers.

5. The above listed mods added to a stock V will take the power from 490 rw hp to around 570 rw hp, a total gain of 80 rw hp and about the same gain in rw torque.

6. The same mods should equal close to 600 rw hp on the new ZL1.

So... what is your experience or knowledge about what CAI may already be included on the ZL1? I'll find out when I get mine, but I am wondering if any changes are really in order for me. I want to keep my warranty intact. I'm pretty sure GM tuned this thing optimally for performance/reliability.