Tuned, Bolt-On 3.7 making stock performance?

[SBPGT]

MPT tuned (91-PRX), upgraded and currently working on Ver. 5. CAI, JBA shorty headers, resonated X-pipe, 2.5" cat-back, new plugs and coil packs. Also, suspension, chassis mods, lightweight wheels and some weight reduction. Data log of 3rd gear from 2000rpm shows timing at 17-18 deg. Read that target timing is 25-27 deg. One reading of knock midway through pull. If I roll onto the the throttle at 3000-3500rpm and go WOT there is no knock and pulls hard. I do notice that IAT's are always 20-30+ degrees over ambient. Closed intake with ram air snout.

AZ at 1000ft. 64F
6-speed automatic with manual shifting mode (Advance Track - off)
0-60 5.7 (Track-App)
1/4" mile 14.1 @ 101 (Track-App)
Dyno 255-258hp 262-265tq

Car and Driver:
6-speed automatic with manual shifting mode
Zero to 60 mph: 5.5 sec
Standing ¼-mile: 14.1 sec @ 102 sec
Dyno 245-250 (many stock dynos on youtube.)

Is anyone having similar results or are mine lower than most? I have heard internet rumors that Arizona, Nevada and California gas is testing lower than advertised. Rumor is that 91 octane is closer to 89 octane.

Also, during the dyno I didn't have access to my car. I couldn't data log and the runs were done with traction control on. I've also heard you need to unplug the "dyno plug" (ABS) in the fender by the filter box. If the ecu sees the rear wheels spinning and the front not turning it will pull timing?

Sponsored

 

[Emilbadal]

I used to have the PRX-91 tune on my car also. The 0-60s didn't change at all from stock. The only difference was how sensitive the gas pedal and how agressive the auto transmission shifts were. It felt faster because of those changes but in reality didn't make any difference time wise. I do believe that the fuel grade in CA does not meet the advertised octane level. While running the 91 tune the knock sensor was reading up to +9 degrees of pulling the timing. I never dug deep into finding if it was a false knock or not. The combination of seeing no improvement in the 0-60 time and how violent some auto trans shifts were(I destroyed the OE 3.15 differential), I just decided to play on the safe side and removed the tune after swapping to FP 3.55 differential.

 

[robvas]

Try some octane booster. Also try a longer pull, with traction taken out of the equation. 60-130 or something like that.

 

[SBPGT]

I've tapped on everything I could reach in the front half of the car with a dead blow hammer, couldn't hear any rattles.

Mixed in a few gallons of 100 octane to bring it up to 95ish. Got the knock down to +1.5 at 5500rpm. Everywhere else it's -2 or less and timing is +22-25 deg. But at 5200-5600 there is a knock and timing drops to +15-18 deg then climbs back up. The AFR's are flat across the rpm range at 12.05.

Maybe I'll try my PRX-93 tune with the higher octane and see what that does? I just wanted a good tune, better performance with the 91 octane since that's whats available.

I think I'll do a few more data logs:
PRX-93 with the higher octane
Stock tune with 91 octane (compare what the stock timing is to the MPT tunes)
And a data log tapping on the exhaust and other places with a small hammer to see if it shows up and what it looks like on the graphs.

 

[Zrussian13]

Az gas isn't great quality and neither is our DA so both those things will effect your numbers. How many miles on your car? It is 9 years old so that might also be adding to its power level.

 

[SBPGT]

95,000 miles. My 120,000 mile '93 2.5L Ford Probe V6 makes 40 more HP with same mods and no tune. That's with drag racing, street racing, autocross and road racing since I bought it. (i know it's two different motors with different histories being used when I bought them.) I assume that things were probably a little more restrictive back then. I was hopping to at least get somewhere between stock and MPT's 93 octane tune(advertised +35hp), not 5hp.

Again. maybe the ecu was pulling timing on the dyno? The car seemed to sound different on the dyno. Sounded like it was maintaining the same exhaust volume instead of getting louder in the upper rpms. Car still feels strong on the street.

 

[SBPGT]

Looks like the PRx-91 tune is targeting around 25 degrees of timing and the PRX-93 tune is shooting for 27 degrees. It is still my original 93 tune no updates. Still knock at 5500rpm except +6.

4 gal of 91 octane mixed with 4 gal of 100 octane should be 95.5 octane but still getting knock. So, it seem that the 91 octane might not be so 91 after all?

I did get from 35 mph to 110 mph .2 of a second faster with the updated 91 tune.

I checked a few logs and noticed the MAP readings at 5500 rpm are at 102 kpa. I thought (from my Megasquirt tuning days) N/A was supposed to max a 100 and boost starts at 100+?

 

[robvas]

102kpa is 0 vacuum

 

[Zrussian13]

Did you do a baseline dyno? Or before timed runs? If not, you really have no idea how much you picked up from the mods. Every engine is different. Maybe it was 5 or maybe it was 40.

If you are seeing +6 knock with 4 gallons of 100 oct in your tank you have false knock issue to address before anything else.

 

[SBPGT]

102kpa is 0 vacuum

So, 100% volumetric efficiency, that's good.

Did you do a baseline dyno? Or before timed runs? If not, you really have no idea how much you picked up from the mods. Every engine is different. Maybe it was 5 or maybe it was 40.

If you are seeing +6 knock with 4 gallons of 100 oct in your tank you have false knock issue to address before anything else.

No baselines. I jumped at opportunities to get parts cheap when I first bought the car (big sales, open box discounts, clearance items and member classifieds). Started modding right from the get go. I've dyno'ed many of my past cars and they've all been pretty consistent with other cars stock dynos. I know I'm making assumptions and also relying on the cars "Track App" for my numbers.

MPT is still working on the tune. I'll get a new dyno after that, with all the traction control and other stuff turned off this time. And, I plan to hit the drag strip next Friday and get real times.

 

[80FoxCoupe]

So, 100% volumetric efficiency, that's good.



No baselines. I jumped at opportunities to get parts cheap when I first bought the car (big sales, open box discounts, clearance items and member classifieds). Started modding right from the get go. I've dyno'ed many of my past cars and they've all been pretty consistent with other cars stock dynos. I know I'm making assumptions and also relying on the cars "Track App" for my numbers.

MPT is still working on the tune. I'll get a new dyno after that, with all the traction control and other stuff turned off this time. And, I plan to hit the drag strip next Friday and get real times.

Map at 0 does not mean 100%ve. It means no vacuum measured in the manifold.

 

[SBPGT]

Map at 0 does not mean 100%ve. It means no vacuum measured in the manifold.

MAP at 102 kpa. Vac. at 0.

The engine is being filled at full atmospheric pressure, can't take in any more. Right?

 

[robvas]

MAP at 102 kpa. Vac. at 0.

The engine is being filled at full atmospheric pressure, can't take in any more. Right?

Not quite.

That just means the engine doesn't have a restriction on the intake side.

You'd have to do a bunch of math to figure out the VE

 

[Zrussian13]

So, 100% volumetric efficiency, that's good.



No baselines. I jumped at opportunities to get parts cheap when I first bought the car (big sales, open box discounts, clearance items and member classifieds). Started modding right from the get go. I've dyno'ed many of my past cars and they've all been pretty consistent with other cars stock dynos. I know I'm making assumptions and also relying on the cars "Track App" for my numbers.

MPT is still working on the tune. I'll get a new dyno after that, with all the traction control and other stuff turned off this time. And, I plan to hit the drag strip next Friday and get real times.

Where did you dyno out here?

 

[SBPGT]

Where did you dyno out here?

I was referred to Black Market Racing and they were the closest to me. On previous cars I did most of my dynos at DynoComp and many mass dyno days around the valley.

Can't believe how much getting a 3 pull baseline dyno cost now!

Sponsored