dyno numbers with GN-1's and roller cam DISSAPOINTMENT

[Slow91z]

The part I think you are missing is you are below the efficiency range of the turbo, so once you get it up some gains will come quick...Then if you really push it hard you will start to get above the "sweet spot" and you will gain less per pound.

 

[Ttype6]

11:1 is a lot richer than it needs to be at that point too. You can probably lean it to 12:1 and pick up even more.

Since he's only running 93 octane,I don't think timing is the thing that is the biggest power limiter for him. I think that what you've stated here is the one single change that will provide the most improvement and I wouldn't be surprised if max power was achieved at 12.5/1 a/f ratio.

 

[Ttype6]

I just had one on the dyno that cal tuned last monday with stock heads on 17 psi made 490 on 110 less injector less cam I would try to match stuff better

What was your A/F ratio?

 

[bison]

my goal would be 450-460 on straight 93 and then 500 plus on 93/alky with full power right at redline (as most people around here love to roll race so id like to hang a little).....

however since the car didnt get any gains from the low boost "rough in tune" im inclined to believe that somthing is mechanicly wrong due to the fact that from the inital 10 lb strart to the 15 lbs finish for this quick dyno session i basicly have 12 hp per pound of boost from 304 at 10 to 364 at 15.

i find it difficult to believe that from 15 lbs to 20 i could gain another 100 hp (basicly gaining obsurd ammounts of power for each pound from this point) kinda feel thats what everyone seems to be hinting at.

ill turn the redline up to 6000 tho....

At that low boost the compressor is probably running in the surge area and I wouldn't expect a big pickup per 1psi until you add timing and get the boost/rpm where the compressor is efficient. To be honest you should pick up more than 20whp per 1psi with the correct fuel and timing.

 

[slimtastic]

Since he's only running 93 octane,I don't think timing is the thing that is the biggest power limiter for him. I think that what you've stated here is the one single change that will provide the most improvement and I wouldn't be surprised if max power was achieved at 12.5/1 a/f ratio.

in genneral ive had the most power with 11.00 afr with stock pistons....as far as i can tell the wot afr is a direct reflection of the quality of airfuel mixing, that being said the stock pistons dont mirror the "heart shape" of the GN1's so my motor makes max power at a rather rich afr...which sucks

At that low boost the compressor is probably running in the surge area and I wouldn't expect a big pickup per 1psi until you add timing and get the boost/rpm where the compressor is efficient. To be honest you should pick up more than 20whp per 1psi with the correct fuel and timing.

hmmmm ill throw a few more pounds at it and see what happens...allthough the backpressure at 15 lbs wasnt ever over 23 lbs.... i gues i should be watching the compressor map as opposed to the backpressure reading? for efficency?

 

[norbs]

I dont think best power would be at 11.0@17 degrees timing, something like 11.7 af @23 degrees on 93 @15 psi boosy, timing would pick things up, but you will make no where near the power compared to un-ported stage 2 heads. If you want to make power 500-600 at lower boost levels you will have to go that route..........

 

[bison]

in genneral ive had the most power with 11.00 afr with stock pistons....as far as i can tell the wot afr is a direct reflection of the quality of airfuel mixing, that being said the stock pistons dont mirror the "heart shape" of the GN1's so my motor makes max power at a rather rich afr...which sucks



hmmmm ill throw a few more pounds at it and see what happens...allthough the backpressure at 15 lbs wasnt ever over 23 lbs.... i gues i should be watching the compressor map as opposed to the backpressure reading? for efficency?

You have a turbo on there that will support 650hp and are running it at about 415hp. I dynoed and raced a stock as assembled from GM bottom end last summer and it made considerably more power at 15psi with a lot leaner tune than you are using. GN1 heads and 212/212. I did have timing optimized for the fuel i was using though. If i recall it made around 400whp@15psi, 465whp at 18psi. Around 530whp@20-21psi and 609@25psi.

 

[bison]

I dont think best power would be at 11.0@17 degrees timing, something like 11.7 af @23 degrees on 93 @15 psi boosy, timing would pick things up, but you will make no where near the power compared to un-ported stage 2 heads. If you want to make power 500-600 at lower boost levels you will have to go that route..........

He would need to re-think the entire thing if he did that and it would be a pooch around town. He would need a solid profile with a lot more duration and lift and build an engine that will peak around 6500rpm. He could go the solid cam with more duration/lift route with the GN1 heads and make just as much power as stage 2 heads if they were race ported tall runner GN1 heads. Simply throwing stage 2 heads on his current engine would get him nothing.

 

[norbs]

He would need to re-think the entire thing if he did that and it would be a pooch around town. He would need a solid profile with a lot more duration and lift and build an engine that will peak around 6500rpm. He could go the solid cam with more duration/lift route with the GN1 heads and make just as much power as stage 2 heads if they were race ported tall runner GN1 heads. Simply throwing stage 2 heads on his current engine would get him nothing.

Oooh, I;m not too sure about stage 2 heads giving him NO HP over his current build, that would be a great dyno test....comparison though. It seems Slim wants big power @low boost?

 

[slimtastic]

Oooh, I;m not too sure about stage 2 heads giving him NO HP over his current build, that would be a great dyno test....comparison though. It seems Slim wants big power @low boost?

i dont want big power at low boost....just 450 at 20. which is reasonable from what i can tell. thanks for your response

 

[norbs]

I don' think anything is wrong, you will need 25 psi boost 24 degees timing c-16@11.5-11.8 af ratio and report back to us......I that all fails you will have to send the heads back to TOM for CNC porting and if that is still not enough stage heads, bigger cam. etc.

 

[Phoneguy]

I don' think anything is wrong, you will need 25 psi boost 24 degees timing c-16@11.5-11.8 af ratio and report back to us......I that all fails you will have to send the heads back to TOM for CNC porting and if that is still not enough stage heads, bigger cam. etc.

Good luck getting the heads worked on by Champion...I couldn't even get a return call from them after multiple calls to them.

Bryan

 

[2QUICK2B6]

tom is a good guy owner of champion ... my man did some tricks an got better #'s

dynos are for show what ET's

 

[A2000RICH]

i would be more concerned with the dyno than the car at this point-------a dyno pull that doesn't represent both torque and RPM accurately is highly suspect and just about useless and should not be relied upon--------dynos do not measure horsepower------they calculate it mathematically from torque and RPM values-------and they need to know both to do it correctly.............RC

 

[norbs]

If he would have logged the injector duty cycle this would give you a ballpark nuimber on the hp he is ,making.

 

[L8TRH8R]

I dont think best power would be at 11.0@17 degrees timing, something like 11.7 af @23 degrees on 93 @15 psi boosy, timing would pick things up, but you will make no where near the power compared to un-ported stage 2 heads. If you want to make power 500-600 at lower boost levels you will have to go that route..........

Going to disagree here, and, agree with Bison. My stock stroke (but bottom end) with GN1's out of the box 212/212 roller 91 octane @14 psi made 593rwhp and 730@ 26 psi. You need to work on your tune and get a dual nozzle kit from Julio, you'll be good to go after that.

 

[vacuum 6]

i dont want big power at low boost....just 450 at 20. which is reasonable from what i can tell. thanks for your response

Take the 6262 off and purchase a TE60. I did it easy.

 

[forzfed]

Going to disagree here, and, agree with Bison. My stock stroke (but bottom end) with GN1's out of the box 212/212 roller 91 octane @14 psi made 593rwhp and 730@ 26 psi. You need to work on your tune and get a dual nozzle kit from Julio, you'll be good to go after that.

He is talking about straight pump gas, not running alky. Great numbers though! What size turbo were you running?

 

[norbs]

Going to disagree here, and, agree with Bison. My stock stroke (but bottom end) with GN1's out of the box 212/212 roller 91 octane @14 psi made 593rwhp and 730@ 26 psi. You need to work on your tune and get a dual nozzle kit from Julio, you'll be good to go after that.

Looks like poor Slim is missing 200 hp+@14 psi. I find those numbers awfully high for 14 psi. What size turbo are you running? UNported heads even?

 

[slimtastic]

Looks like poor Slim is missing 200 hp+@14 psi. I find those numbers awfully high for 14 psi. What size turbo are you running? UNported heads even?

600 hp on 14 lbs isnt possible on a buick 109 motor with just gn1s and a roller cam at the tires.... onless its a mustang dyno with some of the "axle weights" changed