New NA Build for my G35 Coupe!
11-03-2008, 12:32 PM
#21
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jb, I just realized you went with 500cc injectors. Were you reaching 100% with the stock injectors? Also, comparing your power band to mine I have some dips between 1500 rpm and 3000 rpm then it smooths out and your power band seems to come on pretty smooth all the way to your peak. I remember Jeremy had similiar dips in his power band to mine as well. Do you think the haltech is the reason your power band comes on so smooth? As far as your VTC angles, did you have to advance the cams to their maximum between idle and 5500 rpm or does the stock advance work with these cams? Thanks for your input and sharing the details on your build!!!
The VTC and tuning questions will have to be for Jeremy, not me. I know he spent a lot of time tuning my car, but that's really his area. I wasn't even there for most of it.
11-03-2008, 12:39 PM
#22
Very impressive! Sweet! :-)
I remember Jared telling me that raising the redline on a revup required stretching the fuel map, which had a "distortion" effect on the tune requiring a total retune.
Do you have any dynos going up to 8k? Also how's idle with the C8R's?
I remember Jared telling me that raising the redline on a revup required stretching the fuel map, which had a "distortion" effect on the tune requiring a total retune.
Do you have any dynos going up to 8k? Also how's idle with the C8R's?
11-03-2008, 12:44 PM
#23
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Jeremy spent quite a bit of time getting my car to idle correctly and he did a great job. The cams are a bit larger than most people have used in NA motors, but they are smoother than I expected. I made a video yesterday that shows it idling with a few small blips thrown in.
http://www.youtube.com/watch?v=0564nBKrAiw
Sorry, don't seem to be able to embed the video for some reason?
11-03-2008, 01:07 PM
#24
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Thanks, Erin.
It is more involved getting a RevUp to turn high rpm than I was expecting. In all honesty, I am still working on checking and testing a few things.
The problem is that you can't just add a row to any of the OEM ECU tables like you can with a Haltech. Since I have a Haltech, and that is what Jeremy is comfortable tuning, it is used exclusively to control the air/fuel in my car.
Most of the dyno runs were made up to 8000 rpm. The chart I posted at the top of this thread was run to 8000, I suspect. For some reason, Jeremy's dyno was not recording RPM or Torque.
I am very happy with the cams. They behave much better than I expected them to and they really pull on the top end. They are a good match for the 4.08 gears.
The problem is that you can't just add a row to any of the OEM ECU tables like you can with a Haltech. Since I have a Haltech, and that is what Jeremy is comfortable tuning, it is used exclusively to control the air/fuel in my car.
I am very happy with the cams. They behave much better than I expected them to and they really pull on the top end. They are a good match for the 4.08 gears.
That thing must rumble!
11-08-2008, 09:35 AM
#28
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Unfortunately the rpm pickup (I think?) is broken on Jeremy's dyno. None of the dyno charts I have display either the RPMs or the torque. I'm just as curious as you are.
I can say that the new engine has much more power all through the rpm range than my old engine. Torque has definitely improved. Unfortunately, that doesn't quantify anything... sorry.
I can say that the new engine has much more power all through the rpm range than my old engine. Torque has definitely improved. Unfortunately, that doesn't quantify anything... sorry.
11-08-2008, 10:22 AM
#29
Unfortunately the rpm pickup (I think?) is broken on Jeremy's dyno. None of the dyno charts I have display either the RPMs or the torque. I'm just as curious as you are.
I can say that the new engine has much more power all through the rpm range than my old engine. Torque has definitely improved. Unfortunately, that doesn't quantify anything... sorry.
I can say that the new engine has much more power all through the rpm range than my old engine. Torque has definitely improved. Unfortunately, that doesn't quantify anything... sorry.
11-09-2008, 04:25 PM
#30
Congrats JB, Glad you got everything done the way you wanted. I know you have been talking about it for a long while. Congrats man best of luck.
Chris
Get that thing on the track btw...
Chris
Get that thing on the track btw...
Last edited by NA&CH; 11-09-2008 at 04:27 PM.
11-11-2008, 10:27 AM
#32
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My G is so much more fun now... I suspect you might have a few more people interested in building NA motors now... Let me know how things are going and I'll be happy to drive back over...
11-12-2008, 04:51 AM
#33
jb, fantastic build - congrats. Nice work PF! 
Executed so well at so many levels! I figure you've got to do something about that lower plenum and you'll see a nice bump from 6-8k. Cosworth is in your future, me thinks.
Can you or JT tell us how you chose the optimal compression ratio and how you knew it would handle 93 octane?
Can you tell us the rpms when cruising at 65 mph? That will provide a ratio that can be used to convert the graph to rpm and calculate torque figures...
Executed so well at so many levels! I figure you've got to do something about that lower plenum and you'll see a nice bump from 6-8k. Cosworth is in your future, me thinks.
Can you or JT tell us how you chose the optimal compression ratio and how you knew it would handle 93 octane? Can you tell us the rpms when cruising at 65 mph? That will provide a ratio that can be used to convert the graph to rpm and calculate torque figures...
Last edited by rcdash; 11-12-2008 at 04:53 AM.
11-12-2008, 06:39 AM
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Nice build man, very nicely done. I have one question tho. Why stay with a relatively low compression? Its my understanding that many people run 93 octane on 12.0-12.5. I believe the new gt3 using 12.7:1 and still uses 93 octane. I know this is not a VQ and the engine has way more research and money dumped into it for a high performance application, but the VQ is a very well made motor.
the extra .5 or in compression probably wouldnt make a huge difference, but just something iv always woundered about people that do NA builds and dont go with a 12.0:1+ piston, as I would imagine there is still power to be had. Not hating, just asking, as I dont know as much about NA builds as I do FI.
the extra .5 or in compression probably wouldnt make a huge difference, but just something iv always woundered about people that do NA builds and dont go with a 12.0:1+ piston, as I would imagine there is still power to be had. Not hating, just asking, as I dont know as much about NA builds as I do FI.
Last edited by thawk408; 11-12-2008 at 06:43 AM.
11-12-2008, 11:09 AM
#38
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Thanks, Raj!
I've been planning this for so long... It's nice to finally be able to drive it.
Hahaha... You're a mind reader. I think the Cosworth plenum was designed for high rpm NA cars like mine.
Plans are to find a Cosworth plenum and retune it before Jeremy moves up to North Carolina. Jeremy tried to find one while my G was still at his shop, but none were available. I'm not too concerned about getting a first or second edition plenum... I don't think my NA power is going to blow the end caps off like Hal's Z...
Regarding the compresion ratio... Jeremy built an NA motor for himself about a year ago. He went with more compression and ended up being forced to run race gas. He didn't mind, because he didn't plan to drive it on the street. I didn't want to be forced to run race gas for a few more horsepower and opted to run a bit less compression. Jeremy discussed it with JE and decided to go with 11.7:1.
Hmm... I could check, but I'm not sure how the rpm in 6th gear would be relevant when calculating a dyno run in a different gear. I remember Jeremy said he made runs in 4th and 5th gears. Anyway, 80 miles per hour is 3400 rpm in 6th gear. I have 4.08 gears.
Jeremy said the dyno run I posted above started around 3000 rpm and peak power was about 7500 rpm. He ran it up to 8000 rpm on most of the dyno runs.
I've been planning this for so long... It's nice to finally be able to drive it.
Executed so well at so many levels! I figure you've got to do something about that lower plenum and you'll see a nice bump from 6-8k. Cosworth is in your future, me thinks. Can you or JT tell us how you chose the optimal compression ratio and how you knew it would handle 93 octane?
Can you or JT tell us how you chose the optimal compression ratio and how you knew it would handle 93 octane?Plans are to find a Cosworth plenum and retune it before Jeremy moves up to North Carolina. Jeremy tried to find one while my G was still at his shop, but none were available. I'm not too concerned about getting a first or second edition plenum... I don't think my NA power is going to blow the end caps off like Hal's Z...
Regarding the compresion ratio... Jeremy built an NA motor for himself about a year ago. He went with more compression and ended up being forced to run race gas. He didn't mind, because he didn't plan to drive it on the street. I didn't want to be forced to run race gas for a few more horsepower and opted to run a bit less compression. Jeremy discussed it with JE and decided to go with 11.7:1.
Jeremy said the dyno run I posted above started around 3000 rpm and peak power was about 7500 rpm. He ran it up to 8000 rpm on most of the dyno runs.
11-12-2008, 11:22 AM
#39
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Nice build man, very nicely done. I have one question tho. Why stay with a relatively low compression? Its my understanding that many people run 93 octane on 12.0-12.5. I believe the new gt3 using 12.7:1 and still uses 93 octane. I know this is not a VQ and the engine has way more research and money dumped into it for a high performance application, but the VQ is a very well made motor.
the extra .5 or in compression probably wouldnt make a huge difference, but just something iv always woundered about people that do NA builds and dont go with a 12.0:1+ piston, as I would imagine there is still power to be had. Not hating, just asking, as I dont know as much about NA builds as I do FI.
the extra .5 or in compression probably wouldnt make a huge difference, but just something iv always woundered about people that do NA builds and dont go with a 12.0:1+ piston, as I would imagine there is still power to be had. Not hating, just asking, as I dont know as much about NA builds as I do FI.
At the end of the day, it's one of the things that I let Jeremy decide. I told him what I wanted to do with the engine and that's the compression ratio he chose.
Perhaps I could have made a few more horsepower with a bit more compression. I'll leave that to the next NA builder to determine.
11-12-2008, 01:09 PM
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that is great to hear....congratulations...you sound very happy with the car which is what counts....n/a for life
how much $ do you think you have invested in the motor and labor?
how much $ do you think you have invested in the motor and labor?