I had the following on my evo 9 (8K miles)

Walbro 255 lph Fuel Pump
Sun Automotive Exhaust System - Evo Garage HRS Exhaust
Hallman Boost controller PRo RX KIT
Helix EVO 8 hight-flow cat 200 cell
HKS super hybrid panel filters
Tanabe Downpippe 2.75"
Boost Gauge & controller unit
FullRace Pro Stock turbo manifold

Before tuning: baseline on mustang dyno yield 228 ft lb torque, 262 whp. This is way too low on 91 octane.

After tuning it's putting roughly 260 ft-lb 260 whp.

We all expected 300+ wtq and 300+ whp after the tune and baseline should be around 270ish.

The tuner will do a leak test and put in a test pipe. He said it's almost certainly that because of the gas. The day before I was putting 91 from Valero. He said octane 91 at 76 station is totally different.

Is there any other possible reason for this disappointing numbers?

 

who tuned your car?

 

Did you get a base line pull before you added the mods?

 

If the tuner mentioned the gas did he say if the motor was knocking during the pulls, Do you have a dyno graph?

 

First of all dont Mustang Dynos read lower? Isnt this like 300whp ona dynojet?

 

+1

 

I didn't run a baseline on the stock motor.

Yes, he mentioned that it's the knock sensor cut it off and some valve/cam timing was dead low 7.xx

 

+2

 

91 octane and the high flow cat seem like the culprits for low power.

 

Sounds more like a sub par tune or an extremely low reading mustang dyno.

Edit: Just read he put ... Valero gas in his car? Uhhh bad idea.

 

I'm fairly positive it's not the tuner nor dyno machine. They have done many evo 300+. One with similar setup as mine except without the full race manifold and cat was putting down almost 300 whp and wtq. We copy this mappings to mine and it still putting down very low number. Could there be any other reason besides octane rating? They told me cat may clog up too so they're putting in a test pipe now.

 

who installed all the exhasut components. Maybe there is a bad exhaust leak pre turbo?

 

+3 on the tuner, I highly doubt an almost new high flow cat will be clogged. I'd say tell them to pressure test the intake system and actually tune your car specifically instead of copying someone else's map.

 

What dyno? Boost Leak? Knock counts? Need more info.

 

You're putting crap gas in your car but spending money to mod it. Time to rethink your priorities, perhaps.