XKR Super G... Going for Mach 1
#1181
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- Pauter Rods
- JE Forged Pistons with ceramic coating 95.5mm bore
- L19 head studs
- JWT Cams
- JWT HD Valve Springs
- Cosworth Head Gaskets
- TDO5-18G Twin Turbo
- Custom 4'' Front Mount Intercooler
- RC 750cc Injectors
- Custom 3'' down pipes
- APS 3'' dual exhaust
- Custom intake Plenum
here is some of the engine build and I'm running the F-CON V-PRO
- JE Forged Pistons with ceramic coating 95.5mm bore
- L19 head studs
- JWT Cams
- JWT HD Valve Springs
- Cosworth Head Gaskets
- TDO5-18G Twin Turbo
- Custom 4'' Front Mount Intercooler
- RC 750cc Injectors
- Custom 3'' down pipes
- APS 3'' dual exhaust
- Custom intake Plenum
here is some of the engine build and I'm running the F-CON V-PRO
Everything looks good except for the Cometic head gaskets. Cometic head gaskets fail all of the time. Go here for some background:
http://g35driver.com/forums/forced-i...eadgasket.html
JTrain's Cometics failed after 2200 miles, and he wasn't even pushing them that hard.
Better yet, search this forum for "Cometic" and the terms "fail" or "problem".
Go with HKS or HR headgaskets. The HKS are more expensive, but have proven themselves over, and over, and over. The HR headgaskets are about 1/2 the price of Cometics, but are still way better. They have not proven themselves like the HKS head gaskets, so time will tell. Nonetheless, they are proving to hold up better than the Cometics.
If you want to venture into the 800+ hp range, the Cometic headgaskets likely will be your first failure, assuming everything is built and tuned properly. Right now the safe bet is HKS head gaskets. An extra $200 is miniscule in comparison to the total money you will have into this build, and is a very good insurance policy.
If you already have the Cometics installed, good luck, but don't try to push anywhere near 800 whp. That is a disaster waiting to happen.
Last thing, 800 whp is pushing it for 750cc injectors.
Also, some people like RC's, some don't. If everything is smooth once you fire it up and get it tuned, you should be fine for the long term as far as the RC injectors go. When there is a problem, it is usually when they are right out of the box.
Last edited by ttg35fort; 09-16-2009 at 03:03 PM.
#1183
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^ your turbos are WAY smaller than than ones use on XKR's car to make 800 DJ, and you dont have enough fuel to make much past 600 anyhow.
Well kinda....![bowrofl](https://my350z.com/forum/images/smilies/bowrofl.gif)
not the greatest leakdown and a new core was actually used because of a slight taper in the cylinders.
But now, all like new for a great price.![thumbup](https://my350z.com/forum/images/smilies/biggthumpup.gif)
Well kinda....
![bowrofl](https://my350z.com/forum/images/smilies/bowrofl.gif)
not the greatest leakdown and a new core was actually used because of a slight taper in the cylinders.
But now, all like new for a great price.
![thumbup](https://my350z.com/forum/images/smilies/biggthumpup.gif)
![](https://my350z.com/forum/images/smilies/icon08.gif)
#1184
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Yes, the Cosworth head gaskets are Cometics. Just because they have Cosworth stamped on them does not make them any better. I don't work for Cosworth, so I can't speak for them, but I imagine that they use the Cometic head gaskets because they can buy them cheap, stamp their name on them, and then sell them at a huge markup. For naturally aspirated builds, they are probably fine. However, their failure rate on turbo builds far exceeds the failure rate of the HKS head gaskets.
#1185
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Are you Fing!!!!!! kiddingly I did some research before I bought these head gaskets and was told Cosworth used to build F1 motor's and wouldn't put out a product without testing it and there are a good company to go with, how did you find out they are Cometics.
#1187
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http://www.titanmotorsports.com/cohe...hannelid=FROOG
Last edited by Sylvan Lake V35; 09-16-2009 at 03:42 PM.
#1189
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I don't know whether Cosworth is using Cometic head gaskets accross the board, but it is apparent that they are taking at least some Cometic head gaskets for VQ motors and stamping their name on them. Are you talking to an Engineer who knows the VQ motor, or a sales person who spouts the company line he heard in some rah, rah meeting?
You can follow the advice or not. It's your build, your money at risk, and your choice.
Last edited by ttg35fort; 09-16-2009 at 04:09 PM.
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I would love to find out the truth before I have a problem next week please let me know where you guys heard this information because I would love to call the tech back. The tech told me that they designed the gaskets in house and have a company make them. There gaskets are stamped and have a stopper flange and the cometic are laser cut and that makes the edge rough that's why they fail
#1191
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Ya no biggie. I guess all cylinder walls get a lil tapered from the rings. He might not have wanted to wait for the machine shop to rebore when he had new cores sitting around. I assume he at least honed the new core to match the new rings.
Either way, its an all buttoned up motor with no mechanical aspects for me to tamper with
perfect.
but back to the show.... dyno break in must be any day now. how exciting!
Either way, its an all buttoned up motor with no mechanical aspects for me to tamper with
![Smilie](https://my350z.com/forum/images/smilies/smile.gif)
but back to the show.... dyno break in must be any day now. how exciting!
#1192
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I would love to find out the truth before I have a problem next week please let me know where you guys heard this information because I would love to call the tech back. The tech told me that they designed the gaskets in house and have a company make them. There gaskets are stamped and have a stopper flange and the cometic are laser cut and that makes the edge rough that's why they fail
![dunno](https://my350z.com/forum/images/smilies/dunno.gif)
![dunno](https://my350z.com/forum/images/smilies/dunno.gif)
![dunno](https://my350z.com/forum/images/smilies/dunno.gif)
#1193
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Do youself a favor. Use the search feature of this forum and compare the failure rates of Cometic head gaskets to HKS headgaskits in F/I MOTORS.
I don't know whether Cosworth is using Cometic head gaskets accross the board, but it is apparent that they are taking at least some Cometic head gaskets for VQ motors and stamping their name on them. Are you talking to an Engineer who knows the VQ motor, or a sales person who spouts the company line he heard in some rah, rah meeting?
You can follow the advice or not. It's your build, your money at risk, and your choice.
I don't know whether Cosworth is using Cometic head gaskets accross the board, but it is apparent that they are taking at least some Cometic head gaskets for VQ motors and stamping their name on them. Are you talking to an Engineer who knows the VQ motor, or a sales person who spouts the company line he heard in some rah, rah meeting?
You can follow the advice or not. It's your build, your money at risk, and your choice.
#1194
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Ya no biggie. I guess all cylinder walls get a lil tapered from the rings. He might not have wanted to wait for the machine shop to rebore when he had new cores sitting around. I assume he at least honed the new core to match the new rings.
Either way, its an all buttoned up motor with no mechanical aspects for me to tamper with
perfect.
but back to the show.... dyno break in must be any day now. how exciting!
Either way, its an all buttoned up motor with no mechanical aspects for me to tamper with
![Smilie](https://my350z.com/forum/images/smilies/smile.gif)
but back to the show.... dyno break in must be any day now. how exciting!
![Big Grin](https://my350z.com/forum/images/smilies/biggrin.gif)
Any day now.....I guess
![Big Grin](https://my350z.com/forum/images/smilies/biggrin.gif)
When is your motor going in??
Last edited by XKR; 09-16-2009 at 04:25 PM.
#1196
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Since it is already built, at this point don't worry about the head gaskets. That won't accomplish anything. Sometimes, Cometic head gaskets do hold up. Perhaps they are more sensitive than HKS's to installation. I don't know. Hopefully you will be one of those people that don't have any problems with them.
I know the question was directed to Mike, but I am confident in saying that the underbody design is still in R&D.
#1197
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not entirely true....but not exactly what you'd want.
again back to sp, did like 750rwhp at 18psi (that would be pumpgas land) but was up at almost 9krpm and w/ charles plenum
tom
again back to sp, did like 750rwhp at 18psi (that would be pumpgas land) but was up at almost 9krpm and w/ charles plenum
tom
#1198
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Everything looks good except for the Cometic head gaskets. Cometic head gaskets fail all of the time. Go here for some background:
http://g35driver.com/forums/forced-i...eadgasket.html
JTrain's Cometics failed after 2200 miles, and he wasn't even pushing them that hard.
Better yet, search this forum for "Cometic" and the terms "fail" or "problem".
Go with HKS or HR headgaskets. The HKS are more expensive, but have proven themselves over, and over, and over. The HR headgaskets are about 1/2 the price of Cometics, but are still way better. They have not proven themselves like the HKS head gaskets, so time will tell. Nonetheless, they are proving to hold up better than the Cometics.
If you want to venture into the 800+ hp range, the Cometic headgaskets likely will be your first failure, assuming everything is built and tuned properly. Right now the safe bet is HKS head gaskets. An extra $200 is miniscule in comparison to the total money you will have into this build, and is a very good insurance policy.
If you already have the Cometics installed, good luck, but don't try to push anywhere near 800 whp. That is a disaster waiting to happen.
http://g35driver.com/forums/forced-i...eadgasket.html
JTrain's Cometics failed after 2200 miles, and he wasn't even pushing them that hard.
Better yet, search this forum for "Cometic" and the terms "fail" or "problem".
Go with HKS or HR headgaskets. The HKS are more expensive, but have proven themselves over, and over, and over. The HR headgaskets are about 1/2 the price of Cometics, but are still way better. They have not proven themselves like the HKS head gaskets, so time will tell. Nonetheless, they are proving to hold up better than the Cometics.
If you want to venture into the 800+ hp range, the Cometic headgaskets likely will be your first failure, assuming everything is built and tuned properly. Right now the safe bet is HKS head gaskets. An extra $200 is miniscule in comparison to the total money you will have into this build, and is a very good insurance policy.
If you already have the Cometics installed, good luck, but don't try to push anywhere near 800 whp. That is a disaster waiting to happen.
![plus one](https://my350z.com/forum/images/smilies/plus1.gif)
#1200
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One thing I have learned in my 6yrs of FI experience is this **** is never predictable..
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Last edited by Jay'Z; 09-17-2009 at 09:50 AM.