Vengeance VRX3 and Headers only
11-07-2007, 09:31 AM
#21
Just like what's been posted, take a look at the ends of the air-flow. Start at the intake box / filter. If it's factory, then it's not designed first and foremost for power, but rather noise reduction. I'm not familiar with the GTO, but I'd have to guess that you could gain a solid 10-15 hp when you were stock by going with a cold air intake setup. Now that the cam and headers are there, that may jump to 15-20hp. An easy way to check is see if a buddy can loan you a cold air intake setup for an afternoon. Do a dyno with it stock, then toss on the intake and you'd be surprised at the gains you make.
Next look at the end of your exhaust track. Headers are only as good as the pipes after them. If you have a stock catback on the car, you're hurting performance there. Again, I'm not too familiar with the GTO's exhaust setup, but whatever gains you would see on a stock motor going to an aftermarket catback will be increased after doing a cam and headers. An easy way to test this is to undo the exhaust after the cats and test the car on a dyno again.
Again, I go back to the shop vac analogy. Put a sock over the intake, then a sock over the exhaust side and listen to the difference in the sound. Now if you put a bigger motor or more powerful motor with the same inlet and exhaust restrictions, you won't get the anticipated gains.
Spend a couple bucks on the cold air intake first, and see what that gets you. I think you'll be pleasantly surprised.
Next look at the end of your exhaust track. Headers are only as good as the pipes after them. If you have a stock catback on the car, you're hurting performance there. Again, I'm not too familiar with the GTO's exhaust setup, but whatever gains you would see on a stock motor going to an aftermarket catback will be increased after doing a cam and headers. An easy way to test this is to undo the exhaust after the cats and test the car on a dyno again.
Again, I go back to the shop vac analogy. Put a sock over the intake, then a sock over the exhaust side and listen to the difference in the sound. Now if you put a bigger motor or more powerful motor with the same inlet and exhaust restrictions, you won't get the anticipated gains.
Spend a couple bucks on the cold air intake first, and see what that gets you. I think you'll be pleasantly surprised.
11-07-2007, 10:27 AM
#22
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Just like what's been posted, take a look at the ends of the air-flow. Start at the intake box / filter. If it's factory, then it's not designed first and foremost for power, but rather noise reduction. I'm not familiar with the GTO, but I'd have to guess that you could gain a solid 10-15 hp when you were stock by going with a cold air intake setup. Now that the cam and headers are there, that may jump to 15-20hp. An easy way to check is see if a buddy can loan you a cold air intake setup for an afternoon. Do a dyno with it stock, then toss on the intake and you'd be surprised at the gains you make.
Next look at the end of your exhaust track. Headers are only as good as the pipes after them. If you have a stock catback on the car, you're hurting performance there. Again, I'm not too familiar with the GTO's exhaust setup, but whatever gains you would see on a stock motor going to an aftermarket catback will be increased after doing a cam and headers. An easy way to test this is to undo the exhaust after the cats and test the car on a dyno again.
Again, I go back to the shop vac analogy. Put a sock over the intake, then a sock over the exhaust side and listen to the difference in the sound. Now if you put a bigger motor or more powerful motor with the same inlet and exhaust restrictions, you won't get the anticipated gains.
Spend a couple bucks on the cold air intake first, and see what that gets you. I think you'll be pleasantly surprised.
Next look at the end of your exhaust track. Headers are only as good as the pipes after them. If you have a stock catback on the car, you're hurting performance there. Again, I'm not too familiar with the GTO's exhaust setup, but whatever gains you would see on a stock motor going to an aftermarket catback will be increased after doing a cam and headers. An easy way to test this is to undo the exhaust after the cats and test the car on a dyno again.
Again, I go back to the shop vac analogy. Put a sock over the intake, then a sock over the exhaust side and listen to the difference in the sound. Now if you put a bigger motor or more powerful motor with the same inlet and exhaust restrictions, you won't get the anticipated gains.
Spend a couple bucks on the cold air intake first, and see what that gets you. I think you'll be pleasantly surprised.
11-07-2007, 04:22 PM
#24
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I'll start with intake tubing and throttle body and go from there. I'm trying to keep noise down to a minimum because I want to be mindful of my neighbors so I'm not rushing to get a cat-back just yet.
11-07-2007, 05:29 PM
#25
Again, if the exhaust is the choker in your air flow setup, you're not going to get anymore air in than you can get out. So don't be completely surprised if adding a cold air intake only nets 10hp. Remember, air in, exhaust out is where power is made.
11-07-2007, 07:47 PM
#26
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I understand what you're saying, but I'm sure there are some GTO catbacks that at part throttle and idle are only marginally louder than stock but flow a lot better.
Again, if the exhaust is the choker in your air flow setup, you're not going to get anymore air in than you can get out. So don't be completely surprised if adding a cold air intake only nets 10hp. Remember, air in, exhaust out is where power is made.
Again, if the exhaust is the choker in your air flow setup, you're not going to get anymore air in than you can get out. So don't be completely surprised if adding a cold air intake only nets 10hp. Remember, air in, exhaust out is where power is made.
11-07-2007, 08:49 PM
#27
If its a restriction in the intake, it will show up in the datalog as increasing vacuum under WOT. Your tuner should know what to look for.
If you want to test the exhaust system, you need to test the backpressure with a BP gage. Install it in a downstream 02 bung, run the car WOT on the dyno and see what the BP is. Ideally it would be zero. But, real world, it will probably be about 1 psi if the system is free flowing and not restrictive. If its more than 1.5 psi, its costing you some hp. The higher the BP the more it will kill the hp. I have seen 8-9 psi of backpressure cost almost 40 hp.
I would hope your tuner has a backpressure gage. It is a vital diagnostic tool.
11-08-2007, 07:10 AM
#28
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Theres ways to measure and quantify almost anything. Just gotta know how to do it.
If its a restriction in the intake, it will show up in the datalog as increasing vacuum under WOT. Your tuner should know what to look for.
If you want to test the exhaust system, you need to test the backpressure with a BP gage. Install it in a downstream 02 bung, run the car WOT on the dyno and see what the BP is. Ideally it would be zero. But, real world, it will probably be about 1 psi if the system is free flowing and not restrictive. If its more than 1.5 psi, its costing you some hp. The higher the BP the more it will kill the hp. I have seen 8-9 psi of backpressure cost almost 40 hp.
I would hope your tuner has a backpressure gage. It is a vital diagnostic tool.
If its a restriction in the intake, it will show up in the datalog as increasing vacuum under WOT. Your tuner should know what to look for.
If you want to test the exhaust system, you need to test the backpressure with a BP gage. Install it in a downstream 02 bung, run the car WOT on the dyno and see what the BP is. Ideally it would be zero. But, real world, it will probably be about 1 psi if the system is free flowing and not restrictive. If its more than 1.5 psi, its costing you some hp. The higher the BP the more it will kill the hp. I have seen 8-9 psi of backpressure cost almost 40 hp.
I would hope your tuner has a backpressure gage. It is a vital diagnostic tool.
11-08-2007, 07:19 AM
#29
Well the easy way to tell if your exhaust is a restriction is to unclamp the exhaust and dyno the car. If you pick up power, the exhaust is a restriction. For example, I have a magnaflow system and when I dyno'd 430hp, we dropped the magnaflow and I made 431hp, which is dyno variability. If I had made 440 or whatever, I would have seen that the catback was a restriction. Same thing with the cats. Get a section of straight pipe that is identical in length, and swap out the cats for straight pipes. Anything less than a 5hp gain is a wash, but more than 5hp and you realize that the cats are a restriction. In your case, I doubt they are.
To know actually what's a restriction is to find out what they flow cfm wise. Case in point, a 75mm MAF flows considerably less than an 85mm MAF. Once you're intake and throttle body excede the MAF flow ratings, it now becomes the restricitve peice in your intake tract.
To know actually what's a restriction is to find out what they flow cfm wise. Case in point, a 75mm MAF flows considerably less than an 85mm MAF. Once you're intake and throttle body excede the MAF flow ratings, it now becomes the restricitve peice in your intake tract.
11-08-2007, 07:35 AM
#30
Well the easy way to tell if your exhaust is a restriction is to unclamp the exhaust and dyno the car. If you pick up power, the exhaust is a restriction. For example, I have a magnaflow system and when I dyno'd 430hp, we dropped the magnaflow and I made 431hp, which is dyno variability. If I had made 440 or whatever, I would have seen that the catback was a restriction. Same thing with the cats. Get a section of straight pipe that is identical in length, and swap out the cats for straight pipes. Anything less than a 5hp gain is a wash, but more than 5hp and you realize that the cats are a restriction. In your case, I doubt they are.
To know actually what's a restriction is to find out what they flow cfm wise. Case in point, a 75mm MAF flows considerably less than an 85mm MAF. Once you're intake and throttle body excede the MAF flow ratings, it now becomes the restricitve peice in your intake tract.
To know actually what's a restriction is to find out what they flow cfm wise. Case in point, a 75mm MAF flows considerably less than an 85mm MAF. Once you're intake and throttle body excede the MAF flow ratings, it now becomes the restricitve peice in your intake tract.
I'm a stickler for specifics. Dropping the exhaust wont tell me how much restriction there is. I gotta know.
11-08-2007, 08:21 AM
#31
Well, his comment and response to you was that he is 4.5 hours from his tuner. So I'm guessing he doesn't have a BP gauge himself, nor do I for that matter, but I'm sure he's close enough to a dyno. I'm analytical as I'm guessing you are as well, so I like having numbers to quatitate a value, but sometimes you need to go back to basics. Old timers like to pull plugs to see if they are running lean or rich and say they don't need a computer to tell them that.... more than one way to skin a cat I guess.
11-08-2007, 08:30 AM
#32
Well, his comment and response to you was that he is 4.5 hours from his tuner. So I'm guessing he doesn't have a BP gauge himself, nor do I for that matter, but I'm sure he's close enough to a dyno. I'm analytical as I'm guessing you are as well, so I like having numbers to quatitate a value, but sometimes you need to go back to basics. Old timers like to pull plugs to see if they are running lean or rich and say they don't need a computer to tell them that.... more than one way to skin a cat I guess.
As for BP gages, they are pretty damn cheap. I think I paid 65 buck for mine 10 years ago? Cnat see em being much over 100 bucks now. Its one of those tools that once you have it, you wonder how you lived without it.
BTW, I still pull plugs. At the track, and in the shop. Its a good double check.
11-22-2007, 09:55 PM
#33
dude, look at the specs of a vengeance cam compared to stock, if you gain hp with headers and a tuned comp.. stock.. imagine with a cam and improved intake.. Use a quality muffler systel and not bulets .. mine is loud as **** and running crazy but im hoping once i get mined tuned its gonna be a blast.. and i got my lt stainless headers and ypipe for 400, i know deals are out there for gtos too
12-05-2007, 09:16 PM
#34
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Phil,
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....
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....
This is a great GREAT example of COMBO COMBO COMBO. You cant just throw a part on here and there and expect gobs of power. It dosen't work like that. I am bumping this thread in hopes a few more new eyes see this and take a extra minute to think about their setup. You have to see a bunch of small picture's before you can see the big picture.
