G technical help w/ headers
G technical help w/ headers
350Z/G35 mod help
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Anyway, I posted a dyno comparo here before:
http://www.acurazine.com/forums/show...highlight=dyno
Now, I have recently installed headers and here is a post I placed on the Infiniti sites with an update and asking for help:
I've had my Strup headers on for a week and a half. Had the car dyno'd and it was disappointing to say the least. That said, I swear there is a problem. Even more of a problem, my dyno guy had massive computer problems and the email file he sent me of my plot I am having a hard time getting translated to post here.
Suffice is to say, the plot shows a peak gain of 3.7hp to 249.7 and a peak torque gain of 2.2tq to 227.2. However, in some areas I have dropped torque--especially around 3500 rpm's down to 205tq and the curve has gotten more wavy. However, the hp is still entirely steady and peaking, not losing power, and is at least one or two hp higher throughout the range until the peak. Further, the a/f is well over 14 until higher rpm's where it is back to where it was before, though it dips in the 3200-3750 range where my tq curve is dipping, too.
Now, I SWEAR I HERE A PROBLEM, but the car is not throwing a code at all and it isn't a massive 'wooshing' air leak kind of sound. To me, and now maybe my mind is playing tricks on me, the left side of the exhaust sounds louder than the right.
When my shop did my headers, they ordered a whole new gasket from Infiniti and they did tell me one of the header studs gave them massive amounts of trouble on the passenger rear--to the point of having to back it out or something. I guess my questions come in where I have no code present to alert of an issue, and secondly, I don't hear a typical leak one would normally hear, it just sounds really odd at lower rpms--almost like a coffee can with air running through it. Not raspy or anything, just weird in a not good kind of way. I've had headers in other cars of various iterations, this just sounds odd.
Now about the dyno: I only got two pulls in 3rd because the third he wanted to do in 4th for his own edification flapped up his machine in some way (still odd to me, but the car made 212hp/261tq in 4th!!!). Both were virtually identical. My VDC was off, but the slip light (LSD)came on for the second run and stayed on until the car left the machine and I drove it down the street and it then reset. It was 79 degrees outside per the weatherman though the car showed 84 in the shop and it was near 100% humidity. This was almost 20 degrees warmer and I know this makes a difference. Also, the dyno was over 25 miles in stop and go traffic from when I left my office to have it done, contrasting with the 5 miles I drove straight over early in the mornings the last 2 times. It was virtually boiling when dyno'd this last time as opposed to pretty cool the last times.
Now, I did not expect huge gains, but I would have thought to have seen more--especially in the torque gains, and certainly, gains in USEABLE power rather than peak.
Now I also have to say the guys at Stage 6 here is Jax are awesome. Dwight did the install and he also does Titan's work in Orlando on their Supra(s). He has done a couple of Z's, just not a G, but is more of the Supra guru. My dyno guy is a Mustang man and is the Vortech distributor here, he saw nothing out of the ordinary. Both have not deeply looked into the car post install because the car has been hot, but neither sees or hears and obvious problem and both think the code would cause the engine light to come on. The dyno guy knows of Strup products and thinks that there is some sort of problem, though-likely a leak.
Any thoughts from you guys? So far, others seem to think that it is indeed the stud that had to be backed out that is not making a secure fit and that is likely the leak source. I simply thought this would cause a code to flash, or the leaky sound would be more obvious. Additionally, how could this one stud area cause that much of a peformance change? I dunno...
Lastly, my only other planned mod until FI is going to be an exhaust (and I plan to go with the Vortech s/c kit), so I will want an exhaust to work with the s/c. I really wanted to keep the Strup headers with the s/c install, so my question is: before FI, do you see an exhaust opening up more gains post header install--as if the stock exhaust is limiting the benefits of the aftermarket headers as is? I was thinking the Borla or the true dual Stillen exhaust, or exhaust and a/m Y pipe like Nismo--any thoughts???
Sorry about the ramblings and sorry for the lack of the dyno plot, but thinking of all this is driving me nuts this morning...Just needed to unload.
I really thought it was a dyno variance issue, but the sound has me all flapped up as does the wavy torque curve with some loss here and there, and the really high a/f (I would have thought it higher when cooler, not warmer).
Any help would be greatly appreciated...
--------------------------------------------------------------------------------
Anyway, I posted a dyno comparo here before:
http://www.acurazine.com/forums/show...highlight=dyno
Now, I have recently installed headers and here is a post I placed on the Infiniti sites with an update and asking for help:
I've had my Strup headers on for a week and a half. Had the car dyno'd and it was disappointing to say the least. That said, I swear there is a problem. Even more of a problem, my dyno guy had massive computer problems and the email file he sent me of my plot I am having a hard time getting translated to post here.
Suffice is to say, the plot shows a peak gain of 3.7hp to 249.7 and a peak torque gain of 2.2tq to 227.2. However, in some areas I have dropped torque--especially around 3500 rpm's down to 205tq and the curve has gotten more wavy. However, the hp is still entirely steady and peaking, not losing power, and is at least one or two hp higher throughout the range until the peak. Further, the a/f is well over 14 until higher rpm's where it is back to where it was before, though it dips in the 3200-3750 range where my tq curve is dipping, too.
Now, I SWEAR I HERE A PROBLEM, but the car is not throwing a code at all and it isn't a massive 'wooshing' air leak kind of sound. To me, and now maybe my mind is playing tricks on me, the left side of the exhaust sounds louder than the right.
When my shop did my headers, they ordered a whole new gasket from Infiniti and they did tell me one of the header studs gave them massive amounts of trouble on the passenger rear--to the point of having to back it out or something. I guess my questions come in where I have no code present to alert of an issue, and secondly, I don't hear a typical leak one would normally hear, it just sounds really odd at lower rpms--almost like a coffee can with air running through it. Not raspy or anything, just weird in a not good kind of way. I've had headers in other cars of various iterations, this just sounds odd.
Now about the dyno: I only got two pulls in 3rd because the third he wanted to do in 4th for his own edification flapped up his machine in some way (still odd to me, but the car made 212hp/261tq in 4th!!!). Both were virtually identical. My VDC was off, but the slip light (LSD)came on for the second run and stayed on until the car left the machine and I drove it down the street and it then reset. It was 79 degrees outside per the weatherman though the car showed 84 in the shop and it was near 100% humidity. This was almost 20 degrees warmer and I know this makes a difference. Also, the dyno was over 25 miles in stop and go traffic from when I left my office to have it done, contrasting with the 5 miles I drove straight over early in the mornings the last 2 times. It was virtually boiling when dyno'd this last time as opposed to pretty cool the last times.
Now, I did not expect huge gains, but I would have thought to have seen more--especially in the torque gains, and certainly, gains in USEABLE power rather than peak.
Now I also have to say the guys at Stage 6 here is Jax are awesome. Dwight did the install and he also does Titan's work in Orlando on their Supra(s). He has done a couple of Z's, just not a G, but is more of the Supra guru. My dyno guy is a Mustang man and is the Vortech distributor here, he saw nothing out of the ordinary. Both have not deeply looked into the car post install because the car has been hot, but neither sees or hears and obvious problem and both think the code would cause the engine light to come on. The dyno guy knows of Strup products and thinks that there is some sort of problem, though-likely a leak.
Any thoughts from you guys? So far, others seem to think that it is indeed the stud that had to be backed out that is not making a secure fit and that is likely the leak source. I simply thought this would cause a code to flash, or the leaky sound would be more obvious. Additionally, how could this one stud area cause that much of a peformance change? I dunno...
Lastly, my only other planned mod until FI is going to be an exhaust (and I plan to go with the Vortech s/c kit), so I will want an exhaust to work with the s/c. I really wanted to keep the Strup headers with the s/c install, so my question is: before FI, do you see an exhaust opening up more gains post header install--as if the stock exhaust is limiting the benefits of the aftermarket headers as is? I was thinking the Borla or the true dual Stillen exhaust, or exhaust and a/m Y pipe like Nismo--any thoughts???
Sorry about the ramblings and sorry for the lack of the dyno plot, but thinking of all this is driving me nuts this morning...Just needed to unload.
I really thought it was a dyno variance issue, but the sound has me all flapped up as does the wavy torque curve with some loss here and there, and the really high a/f (I would have thought it higher when cooler, not warmer).
Any help would be greatly appreciated...
Originally Posted by JPsZ
you have the stock exhaust right? how can one side be louder when both pipes come from 1 muffler and 1 pipe?
Hey r10apple - sorry to hear about your troubles. must be very frustrating. the only time I've ever heard of similar issues with these or any other headers is due to a leak. My suspicion would be to check ALL of the flange bolts where it bolts up to the engine. Some of those bolts are challenging to get to, and if they all aren't torqued down completely to specs.
There may also be an issue with the oxygen sensor wires not being plugged back in, or just not correctly. This might not be the issue you're experiencing, but it's worth checking.
Definitely check those 14mm bolts for correct torque specs, and that there are no issues with the gaskets used. Good luck in figuring it out, and let us know how you make out. I promise you that these headers will give you more than 3HP and 2ft/lbs of TQ!
There may also be an issue with the oxygen sensor wires not being plugged back in, or just not correctly. This might not be the issue you're experiencing, but it's worth checking.
Definitely check those 14mm bolts for correct torque specs, and that there are no issues with the gaskets used. Good luck in figuring it out, and let us know how you make out. I promise you that these headers will give you more than 3HP and 2ft/lbs of TQ!
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250hp seems right with the mods u currently have now. U have to remember that mods work together to produce hp so maybe the mods u had before the headers were very efficient. Therefore, adding the headers to your orginal mods only improved the peak hp by a few more hp. I only made 232hp with plenum, headers, cat, and y pipe so I would imagine 250hp sounds right on the money.
Originally Posted by Mr_pharmD
250hp seems right with the mods u currently have now. U have to remember that mods work together to produce hp so maybe the mods u had before the headers were very efficient. Therefore, adding the headers to your orginal mods only improved the peak hp by a few more hp. I only made 232hp with plenum, headers, cat, and y pipe so I would imagine 250hp sounds right on the money.
I have had a few people send me pm's with dyno plots: the headers gained a lot of power across the spectrum, and most got 10-15 peak hp/tq as well. This tells me I have an install issue to solve...
Just to add to this in case someone ever does a search and has had the same problem as me, I really believe this is the solution and it is quanitifed perfectly:
Originally Posted by DrRabbitFurHead
you cannot tighten the header bolt any more IF they backed out the stud going into the block. It is threaded on BOTH sides and I'm saying that the stud isn't screwed into the block far enough. The nut over the header is as tight as it can be, but the header bolt needs to go into the block more to make the header flange mate to the block.
The problem is... STEEL bolt and ALUMINUM block. The steel is probably cross threaded due to them backing the bolt out and not being able to get the proper tools in to install it properly.
My car was messed up pretty bad on BOTH sides. The last bolts closest to the passengers were backed out and not threaded back in properly. The only tool you can get on the bolt is a torex fitting (and it's really small). Couple the size with the length of the bolt and you've got a nightmare on your hands.
Odds are you will have to back out the bolt, cut it to 1/2 it's size, rechase the thread and then bolt it back in. Just make sure to measure and remeasure so the bolt is at least 5 threads longer than the header flange.roblem, this to me seems like this is indeed the solution and it is quantified perfectly:
Originally Posted by DrRabbitFurHead
you cannot tighten the header bolt any more IF they backed out the stud going into the block. It is threaded on BOTH sides and I'm saying that the stud isn't screwed into the block far enough. The nut over the header is as tight as it can be, but the header bolt needs to go into the block more to make the header flange mate to the block.
The problem is... STEEL bolt and ALUMINUM block. The steel is probably cross threaded due to them backing the bolt out and not being able to get the proper tools in to install it properly.
My car was messed up pretty bad on BOTH sides. The last bolts closest to the passengers were backed out and not threaded back in properly. The only tool you can get on the bolt is a torex fitting (and it's really small). Couple the size with the length of the bolt and you've got a nightmare on your hands.
Odds are you will have to back out the bolt, cut it to 1/2 it's size, rechase the thread and then bolt it back in. Just make sure to measure and remeasure so the bolt is at least 5 threads longer than the header flange.roblem, this to me seems like this is indeed the solution and it is quantified perfectly:
FYI:
No header leak, peeps. We tried a tissue on a coat-hanger test, baby power test, etc. All seems in perfect working order.
Another lightly modded G was found in my neighborhood as well. I listen to it--granted, a 2003 MT, and it appears it is my headers that are indeed making the noise, but again, no leak is detected and I have no code on the 'ol dash.
It looks like that means I saw less than 4hp/4tq gains with the Strup headers. In looking further, we had another guy in their shop who operates a dyno elsewhere (Velocity) and he looked at hte Z graph of the Strup headers pre/post install. The gains were relatively uniform from the stock plot. That being said, mine are relatively uniform as well, just with less than the 17hp/20tq gained on the stock Z.
Oh well...At least we know the headers--at least the Strups--aren't really producing noticable gains when used with my other mods. I think replacing the exhaust will liven things up a bit more, but I just bought a brush guard for the Sequioa, new Bikini top, winch and cover for the Jeep, so with that and all our trips coming up, I'll probably wait until later this summer...
For now, seems to be you can't beat the pulley/intake/grounding kit/plenum spacer combo ($890)--and those--even if you paid for install--would still be less than/same as the headers and their install alone ($1050), and they provided over 20hp/10tq-though it was often 15-20tq greater throughout the spectrum rather than simply peak power...
No header leak, peeps. We tried a tissue on a coat-hanger test, baby power test, etc. All seems in perfect working order.
Another lightly modded G was found in my neighborhood as well. I listen to it--granted, a 2003 MT, and it appears it is my headers that are indeed making the noise, but again, no leak is detected and I have no code on the 'ol dash.
It looks like that means I saw less than 4hp/4tq gains with the Strup headers. In looking further, we had another guy in their shop who operates a dyno elsewhere (Velocity) and he looked at hte Z graph of the Strup headers pre/post install. The gains were relatively uniform from the stock plot. That being said, mine are relatively uniform as well, just with less than the 17hp/20tq gained on the stock Z.
Oh well...At least we know the headers--at least the Strups--aren't really producing noticable gains when used with my other mods. I think replacing the exhaust will liven things up a bit more, but I just bought a brush guard for the Sequioa, new Bikini top, winch and cover for the Jeep, so with that and all our trips coming up, I'll probably wait until later this summer...
For now, seems to be you can't beat the pulley/intake/grounding kit/plenum spacer combo ($890)--and those--even if you paid for install--would still be less than/same as the headers and their install alone ($1050), and they provided over 20hp/10tq-though it was often 15-20tq greater throughout the spectrum rather than simply peak power...
Originally Posted by SpeedRcr
you will reach a point where n/a bolt ons don't do much combined together until you get the car retuned...save up and invest in a utec
I had some problems with my header install. After the post by the tech at Technosquare about resetting my ECU, well, thanks a ton!!!
I did reset my ECU and had the car redyno'd today. Granted it is cooler (55 degrees at dyno time), but the reset instructions really seemed to help by the butt dyno. I have now hit 255.6hp(245.8hp SAE corrected) and 235.6tq(229.8 tq (SAE corrected). Torque stays over 210tq until almost 6200 rpms...
I'll try and post the dyno plot later tonight. I really appreciate you guys and the input some of you gave here and by PM.
Overall, I am pleased that it was only $2k to make almpt 30hp/15tq and more importantly, 35tq in useable gains over 2k-4500 rpms. Certainly beats the 233hp/196tq TL-S with all of the bolt-ons but exhaust. Now if I can beat the TL-S's (yup, with spare, gas and normally inflated tires) 14.237 1/4 mile, I'll be really happy...
I did reset my ECU and had the car redyno'd today. Granted it is cooler (55 degrees at dyno time), but the reset instructions really seemed to help by the butt dyno. I have now hit 255.6hp(245.8hp SAE corrected) and 235.6tq(229.8 tq (SAE corrected). Torque stays over 210tq until almost 6200 rpms...
I'll try and post the dyno plot later tonight. I really appreciate you guys and the input some of you gave here and by PM.
Overall, I am pleased that it was only $2k to make almpt 30hp/15tq and more importantly, 35tq in useable gains over 2k-4500 rpms. Certainly beats the 233hp/196tq TL-S with all of the bolt-ons but exhaust. Now if I can beat the TL-S's (yup, with spare, gas and normally inflated tires) 14.237 1/4 mile, I'll be really happy...
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