Dyno results of GT with x pipe
10-11-2005, 04:37 PM
#2
Supercharged
Rennlist Member
Rennlist Member
Join Date: May 2002
Location: Back in Michigan - Full time!
Posts: 18,925
Likes: 0
Received 60 Likes
on
34 Posts
I assume this is without cats. Did the car have cats before the X-pipe? Either way, it looks very good! 
Tell Roger to order another one!
Tell Roger to order another one!
10-11-2005, 04:38 PM
#3
Rennlist Member
Hi Ernest,
Were the cats deleted for the "before" results, or were they deleted when the X pipe was fitted ?
Ooops ! Andrew and I posted at the same time :-)
Regards
Were the cats deleted for the "before" results, or were they deleted when the X pipe was fitted ?
Ooops ! Andrew and I posted at the same time :-)
Regards
Trending Topics
10-11-2005, 04:49 PM
#8
Drifting
That's about what I expected. Your little bump glitch at the end of the stock run is what gave you the 294 rwhp number. If you figure 285ish for a real peak, that's 25rwhp with cats. Now you need to take them off and go off howling...
Shall I put you down for one Ernest?
Shall I put you down for one Ernest?
10-11-2005, 05:12 PM
#9
Race Car
Check out that increase starting down at 3000 RPM. And to expand off Dave's comment, I cannot see where the baseline HP graphs really goes any higher than the "Max Torque" label on the graph. The top of the red Max Torque label seems to be a hair over the 290 scale, lets say 291. I think you got 20 HP peak at the wheels with cats!!! But what is more important to me is how much of the curve is showing 15 or better. These are super results!
You do not seem to need a GTS.
Good show!
You do not seem to need a GTS.
Good show!
10-11-2005, 05:18 PM
#10
Rennlist Member
Thread Starter
Join Date: Mar 2003
Location: Nashua, NH
Posts: 4,328
Likes: 0
Received 0 Likes
on
0 Posts
Actually, it's 19 HP at the rear wheels. The base run peaked at 294, but leveled out at 291. The X pipe run leveled out AND peaked at 310. It's already pretty loud with the cats, not illegal or unpleasant, just louder than with the RMB.
10-11-2005, 05:20 PM
#11
Race Director
The curve is good...figure a steady 10hp & 20ftlb torque gain starting at only 3500rpm!! 310rwhp is about 365hp at the crank!! That is a very good for just an x-pipe...but your car dyno'd strong before too...even 285 rwhp makes about 335 crank or a solid 10hp more than it should! Your A/F is good too!
10-11-2005, 05:32 PM
#12
ignoring the peak numbers...its the area under the curve...(yea..mark K.. 
) . Nice gains through the entire band...torque and HP...
Nice to see.. Great numbers.
now pick up a piggy back computer and nail the a/f to 12.5 to 13 range..and see some more power
later,
Tom
89GT
) . Nice gains through the entire band...torque and HP...Nice to see.. Great numbers.
now pick up a piggy back computer and nail the a/f to 12.5 to 13 range..and see some more power
later,
Tom
89GT
10-11-2005, 05:43 PM
#13
Rennlist Member
No dyno near the Ranch but confirm seat of the pants power hit is now just above 3k rpm with Motorsport X, GT resonators and RMB.
I may be running a little lean at very high speed (WOT +3rd gear) at altitude of +3000 ft..................any thoughts Dave?
I may be running a little lean at very high speed (WOT +3rd gear) at altitude of +3000 ft..................any thoughts Dave?
10-11-2005, 06:37 PM
#14
Rennlist Member
That is awesome results and closely matches our in house results on a S4 auto with our cat/air piped system and stock exhaust very closely. We have a few mors tests to do though ... need a local GT for testing .... anyone?
Need to put a rising rate reg on to extract a tick more power.
Hopefully, the graph is attached....it is not the highest nor the lowest....
Need to put a rising rate reg on to extract a tick more power.
Hopefully, the graph is attached....it is not the highest nor the lowest....
10-11-2005, 06:43 PM
#15
Drifting
Higher altitude actually makes cars run richer not leaner. If you hook up a DVM to the O2 sensor output you can make a cheap and easy A/F meter. I built a jig that goes inline for testing that works great but I use it enough I can't send it to Canada. Just tapping into the black wire on the O2 sensor you should be able to read the voltage. If it's at .75 to .85 VDC you are OK. That is at WOT and higher rpm (4k plus) when the car reverts to the proprogrammed map and is no longer operating in closed loop.
Almost any exhaust improvements you do to your car will cause the engine to run leaner as you have increased it's airflow efficiency without adding more fuel. Normally with just an X-over you are still OK and within factory variables. When I added our cat back system to one of our dyno mules it went way too lean and whereas the cat back gained 11hp and 15#'s of torque on the stock cats, it only gained 4hp with the X-over. Getting more fuel to it would have given me much better numbers but that wasn't the purpose of that exercise.
Almost any exhaust improvements you do to your car will cause the engine to run leaner as you have increased it's airflow efficiency without adding more fuel. Normally with just an X-over you are still OK and within factory variables. When I added our cat back system to one of our dyno mules it went way too lean and whereas the cat back gained 11hp and 15#'s of torque on the stock cats, it only gained 4hp with the X-over. Getting more fuel to it would have given me much better numbers but that wasn't the purpose of that exercise.