Back from the dyno and disappointed

[RussMcB]

Send the results (especially the AFR graph) to Marc and he'll know what changes to make.

Unfortunately it is an iterative process, but Marc is great to work with, so with some patience you'll get to where it should be.

Just curious - Before you saw the dyno numbers, how were you feeling about how the car ran? Did it feel like it was running stronger than a 4hp increase?

[Billy Mild]

Originally Posted by XfireZ51

Looks like your last run was your best run. What was the coolant temp for these runs? You should also ask them to use SAE correction and provide a graph using rpm instead of mph. In fact, I always request the run file so I can look at it on my own laptop.
And yes a leaner AFR will make a difference. Any change to timing?

Coolant temp according to my temp gauge is right about half way. The fans are programmed to come on at 205 and kick off at 200. I will request the runfile. I don't see why they wouldn't give it to me.

Would rich/fat tuning make for a much lower than expected HP number? I feel that only about 10 HP will be on the table with a leaner tune. Correct me if I am wrong.

Originally Posted by RussMcB

Send the results (especially the AFR graph) to Marc and he'll know what changes to make.

Unfortunately it is an iterative process, but Marc is great to work with, so with some patience you'll get to where it should be.

Just curious - Before you saw the dyno numbers, how were you feeling about how the car ran? Did it feel like it was running stronger than a 4hp increase?

I was going to talk to Marc today on the phone and let him know what happened.

I haven't been romping on my car much since I got the exhaust done. I ran Marc's tune before I actually got the headers installed. It has been running so much better from a driveability standpoint. It is smoother everywhere. No hesitations in the powerband or anything. Pulls right up to Redline too.

Its hard for me to tell if my car is pulling harder than before only because it was a decent amount of time from when I drove it with stock headers than with SW headers and new exhaust. I would say yes, but I haven't driven it much. I got the headers on Friday, Saturday did the exhaust work, then Sunday was dyno day. I was running around tying up any loose ends to make sure I was ready for the dyno.

Guys, don't take this as me hating on Marc or anything of the sort. He has been great to work with thus far on my Throttle body and tune. I am going to call him today about the tune and see what his suggestions are. I'm just curious WTF happened to produce such a minimal increase for the exhaust mods.

[BigJohn]

A stock 375 hp with 15% lost in drive train is 318.65 hp at wheels.
389 hp with 15% lost in drive train is 330.65 hp at wheels.
393 hp with 15% lost in drive train is 334.05 hp at wheels.
Have you modified your intake before the throttle body?

[Jim Nolan]

I'm a little confused with your dyno sheet? Where is the RPM numbers. You could be running it in 5th gear at 100mph and I don't think you will reading the correct hp output. I originally had just plenum, injector housing and horn ported and stock exaust manifold with a corsa catback system with a Haibeck chip and put out 357.8 rwhp at 5300 rpm. That's when the hp started to drop off thru 7k. With the heads ported, cams reset, sw headers and dyno tune it put out 397.8 hp. The interesting part was that hp peaked out at 6500 rpm but never dropped off thru 7k. Can anybody chime in if I'm wrong? Good luck

Jim

[RussMcB]

Originally Posted by Billy Mild

Would rich/fat tuning make for a much lower than expected HP number?

Yes! "Lean is mean". :-)

Originally Posted by Billy Mild

I feel that only about 10 HP will be on the table with a leaner tune. Correct me if I am wrong.

Good question. I have a hunch, but don't know for sure. My car got a huge bump when I gave it to a tuner and they ran many dyno runs and making many adjustments. It would be interesting to hear a substantiated answer to that question. May be a good one to ask Marc.

[Billy Mild]

Originally Posted by BigJohn

A stock 375 hp with 15% lost in drive train is 318.65 hp at wheels.
389 hp with 15% lost in drive train is 330.65 hp at wheels.
393 hp with 15% lost in drive train is 334.05 hp at wheels.
Have you modified your intake before the throttle body?

All runs were made in 4th gear except for 1. My car with just a modified airlid K&N filter and borla axleback exhaust with center resonator delete put down 330 WHP in the Fall of 2014.

Adding in Headers, high flow cats, x pipe, and Haibeck tune only managed to get 334 WHP. If you look at the dyno sheets one day was at 74 degrees(first dyno) and yesterday was 95 degrees(second dyno sheet).

I have done nothing for the intake or TB. The TB was polished by Marc in order to fix my sticky throttle blades.

[Billy Mild]

Originally Posted by RussMcB

Yes! "Lean is mean". :-)

Lean is mean until you tune a 2 stroke, then it means tick tick, BOOM. LOL. Ask me how I know.

[BigJohn]

Sometimes the hose will compress and restrict air into throttle body.

[Billy Mild]

Originally Posted by BigJohn

Sometimes the hose will compress and restrict air into throttle body.

I didn't even pay attention to that when it was being dyno'd as I was behind the car.

[Kevin]

if you have a factory duct that's not reinforced we found your problem