Vengeance VRX3 and Headers only
11-05-2007, 07:37 AM
#1
Jedi Master
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Vengeance VRX3 and Headers only Someone please tell me why my power dips at 3.5k. Only mods I have are the cam and headers with cats.
If graph doesn't work for you try going to this link that has dyno sheet and dyno sheet with AFR:
http://ls1gto.com/forums/showthread.php?t=198889
If graph doesn't work for you try going to this link that has dyno sheet and dyno sheet with AFR:
http://ls1gto.com/forums/showthread.php?t=198889
Last edited by Gh0st; 11-06-2007 at 10:50 AM.
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11-06-2007, 09:20 AM
#8
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Was it tuned for that cam? Usually some timing around the peak torque area will flatten that dip out. Hard to say without seeing a log, tune or A/F data though.
11-06-2007, 11:54 AM
#11
From the website link, graph still doesnt work....
The fact is you do not have the proper mods to support the cam, the tuner can do only so much for WOT, ANY ODB2 PCM will need time to relearn and re adjust. Drive it and get it retuned.
Your top end is suffering, a properly supported car has made 400+, your down about 40 hp.
This is a PURE cam/headers only car. I have no intake, no tb, no pulley, nothing.
My numbers are about 365/355 with VRX3 cam and Kook's headers only. Cam is 226/228 581/585 or something.
Question though, on my dyno sheet, from 3.5k to 4.5k, my car actually dips in power and then goes back up at 4.5k. What could be causing this? Shop guys said it was because of a lack of bolt-ons which makes no sense. Why would my torque and HP dip down like that but pick up again if it was bolt ons choking me? Wouldn't the top end suffer more?
.
My numbers are about 365/355 with VRX3 cam and Kook's headers only. Cam is 226/228 581/585 or something.
Question though, on my dyno sheet, from 3.5k to 4.5k, my car actually dips in power and then goes back up at 4.5k. What could be causing this? Shop guys said it was because of a lack of bolt-ons which makes no sense. Why would my torque and HP dip down like that but pick up again if it was bolt ons choking me? Wouldn't the top end suffer more?
.
Your top end is suffering, a properly supported car has made 400+, your down about 40 hp.
11-06-2007, 01:21 PM
#12
Phil,
I have attached a dyno graph for you to look at. This graph represents a 6spd F Body with tuning. He is making 340/337 before the addition of the camshaft
We add PaceSetter Longtubes/VRX3 Camshaft. Customer is now making 352/349.... Thats a gain of 12rwhp/12rwtq... Obviously this is very minimal.... We explain to the customer that headers are only going to add so much if pushing through a stock 98 catback... The cam is only going to help so much if sucking thru a stock airbox/LS1 intake/Stock TB etc etc....
Customer was pretty upset and didnt believe us about his combo... I made him an offer. I told him to come back and complete his SUPPORTING mods and if he didnt make 385rwhp I would GIVE him all of the mods... Guess what... A Ported throttlebody/LS6 Intake/ Single Cutout produced 386/377 with no underdrive pulley, junk 98 LS1 Heads and less than exceptional headers/exhaust.... Thats a gain of 46rwhp/40rwtq with a MILD camshaft/ported TB/LS6 intake/Junk headers...
My point is, just adding a camshaft will not give you the benefit you are looking for UNTIL you add the mods required to SUPPORT the camshaft.. IE SUPPORTING BOLT ONS....
Your tune is fine. You watched your car being tuned... Scanned with GM Tech II/EFI Live/DynoJet Wideband... GTOs are extremely heavy cars and can not take alot of timing in the midrange without detonating. Your car has a very safe tune in it to ensure you dont get knock or any other issues...
Finish your car. Im sure you will be happy.
I have attached a dyno graph for you to look at. This graph represents a 6spd F Body with tuning. He is making 340/337 before the addition of the camshaft
We add PaceSetter Longtubes/VRX3 Camshaft. Customer is now making 352/349.... Thats a gain of 12rwhp/12rwtq... Obviously this is very minimal.... We explain to the customer that headers are only going to add so much if pushing through a stock 98 catback... The cam is only going to help so much if sucking thru a stock airbox/LS1 intake/Stock TB etc etc....
Customer was pretty upset and didnt believe us about his combo... I made him an offer. I told him to come back and complete his SUPPORTING mods and if he didnt make 385rwhp I would GIVE him all of the mods... Guess what... A Ported throttlebody/LS6 Intake/ Single Cutout produced 386/377 with no underdrive pulley, junk 98 LS1 Heads and less than exceptional headers/exhaust.... Thats a gain of 46rwhp/40rwtq with a MILD camshaft/ported TB/LS6 intake/Junk headers...
My point is, just adding a camshaft will not give you the benefit you are looking for UNTIL you add the mods required to SUPPORT the camshaft.. IE SUPPORTING BOLT ONS....
Your tune is fine. You watched your car being tuned... Scanned with GM Tech II/EFI Live/DynoJet Wideband... GTOs are extremely heavy cars and can not take alot of timing in the midrange without detonating. Your car has a very safe tune in it to ensure you dont get knock or any other issues...
Finish your car. Im sure you will be happy.
11-06-2007, 01:32 PM
#13
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Thanks for the response Ron! As I said to you in a PM, I'm still trying to learn this stuff and in no way am I trying to give Vengeance a bad name as my ignorance is quite clear at times 
I'll do as you guys say and I'll go from there.
I'll do as you guys say and I'll go from there.
11-06-2007, 07:34 PM
#14
Everyone knows a motor is just an air pump, but here's a little further analogy.
Look at that air pump with a bunch of chambers along the way before and after the pump, kind of like a shop-vac vaccum cleaner. If you open up the middle of that pipe, lets say the inlet to the vaccum canister, but still have a skinny 1" hose in front of the inlet, you're gain is going to be minnimal. Continuing the analogy, if you have an exit hose on the vaccum cleaner, for arguments sake, no matter how big the inlet hose is, the motor on the shop-vac can only push so hard on the exhaust side.
As you're doing mods, realize that each mod should be sufficient to meet your future intended goals. If you never want to touch the inside of the motor, no heads or cams in your future, you may be okay with an ls6 intake, normal air lid, and catted ypipe with mid length headers. But when you add a big ole cam, realize that those other bolt ons in front of and behind that air pump are going to restrict the results.
That's why if you take a stock exhaust motor, manifolds and catback, throw on the best heads in the world with a matched cam, a ported FAST intake, 85mm maf and lid and guess what, you're not going to see 400hp at the wheels. Add a set of long tube headers with an off road ypipe with a cutout and you just gained 50-60hp from doing headers.
Obviously the cam you went with needs the additional supporting mods to take full advantage of the power of the cam.
Look at that air pump with a bunch of chambers along the way before and after the pump, kind of like a shop-vac vaccum cleaner. If you open up the middle of that pipe, lets say the inlet to the vaccum canister, but still have a skinny 1" hose in front of the inlet, you're gain is going to be minnimal. Continuing the analogy, if you have an exit hose on the vaccum cleaner, for arguments sake, no matter how big the inlet hose is, the motor on the shop-vac can only push so hard on the exhaust side.
As you're doing mods, realize that each mod should be sufficient to meet your future intended goals. If you never want to touch the inside of the motor, no heads or cams in your future, you may be okay with an ls6 intake, normal air lid, and catted ypipe with mid length headers. But when you add a big ole cam, realize that those other bolt ons in front of and behind that air pump are going to restrict the results.
That's why if you take a stock exhaust motor, manifolds and catback, throw on the best heads in the world with a matched cam, a ported FAST intake, 85mm maf and lid and guess what, you're not going to see 400hp at the wheels. Add a set of long tube headers with an off road ypipe with a cutout and you just gained 50-60hp from doing headers.
Obviously the cam you went with needs the additional supporting mods to take full advantage of the power of the cam.
11-07-2007, 07:16 AM
#18
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How do you determine the weak link though? I already have long tubes and true dual exhaust, albeit stock.
Would it be best if I look at a PTB and after-market intake tubing or keep stock intake tubing and switch to a FAST 90/90 setup?
This is where I struggle because I don't want to just throw parts at my car. I like being somewhat scientific and finding out what really is needed to maximize my power. Is there any way I can figure this out or am I just going to have to throw parts at it?
Would it be best if I look at a PTB and after-market intake tubing or keep stock intake tubing and switch to a FAST 90/90 setup?
This is where I struggle because I don't want to just throw parts at my car. I like being somewhat scientific and finding out what really is needed to maximize my power. Is there any way I can figure this out or am I just going to have to throw parts at it?
11-07-2007, 09:19 AM
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How do you determine the weak link though? I already have long tubes and true dual exhaust, albeit stock.
Would it be best if I look at a PTB and after-market intake tubing or keep stock intake tubing and switch to a FAST 90/90 setup?
This is where I struggle because I don't want to just throw parts at my car. I like being somewhat scientific and finding out what really is needed to maximize my power. Is there any way I can figure this out or am I just going to have to throw parts at it?
Would it be best if I look at a PTB and after-market intake tubing or keep stock intake tubing and switch to a FAST 90/90 setup?
This is where I struggle because I don't want to just throw parts at my car. I like being somewhat scientific and finding out what really is needed to maximize my power. Is there any way I can figure this out or am I just going to have to throw parts at it?
What did you expect man? I'd bet with a CAI and a *complete* exhaust, and a re-tune you'd pick up 25-30rwhp.