I made it to the dyno at RS Motors last Saturday, and here is how things turned out:


All tuning and pulls were done on 93 octane in 4th gear. I had been hoping for more power, but I did go back to a stock air box and reset my Piper Cams to neutral settings. On the detail you can see where I have some tuning to do:


Boost is jumping to just under 23 lbs and then falling evenly to 17 lbs at 7800 rpms. Vishnu has a fix that should cut the rate of taper some. The big issue for me is the drop after 6500 rpms; I'm not sure if this is related to my new cam timing or my switching back to a stock intake and air box. The rough spot at about 5500 rpms is being caused by cell transitions; I can smooth that out, but didn't want to spend any more time on the dyno until I figured out the boost and top end issues.

Total power mods are: XEDE + XEDE Flash, Piper Rally cams, ported head with larger valves, 10.5 cm hotside, 3" Turbo back exhaust, and a walbro 255 fuel pump. Again, all testing/tuning done on 93 octane with 4th gear dyno pulls.

 

The HP looks good but your tourqe seems low to me.

 

It looked that way to me also, but then both curves are different from what I'm used to seeing here. On the road, the car drives like a beast, except the top end feels weak.

 

Back from the dead, and here's an update of what I found in the post-mortum.

First, the head gasket wasn't holding - there was a problem with the machine work on the deck of the head. I've had that fixed and the repaired head should go in tonight.

Second, I think my Pipers might not be quite up to the flow of the head. They made great power before (about 300 whp on this dyno after some tuning) but that was before I added the ported head and 10.5 hotside. I have some new HKS 280s arriving tonight or tomorrow so we'll see how they work out.

Third, I'd like to hold a bit more boost to red line. I've done some research and think I have found a way to keep the XEDE and ECU in control, but allow the car to hold more boost.

Not related, but I'm also planning to re-install my K&N Typhoon filter, removing it didn't improve idle stability, which was why I changed back to the stock intake. I'm hoping the improvements in the V3 version of the XEDE software and switching to the HKS cams will help.

The new parts should be installed and ready to go by tomorrow evening sometime and my friends at RS Motors are going to keep the shop open for a late evening dyno session. Hopefully things will look better this time around.

 

The head is back in along with the new HKS 280s and my old Typhoon intake. After a 700 mile road trip everyhting seems to be settling in fine without any mechanical issues.

The V3 software update is in and running. Unfortunately with all the new parts my old maps are pretty much useless so it's back to the dyno to get the car running correctly again.

Boost trick #1 didn't quite give me the result I expected; it introduced a mild flutter into my stock BOV. Time to try a different solution.

Between having a torque wrench blow out in the middle of torquing the head and the problems I had initially with the V3 update, I passed on trying to rush onto the dyno last Friday. I expect to be on the dyno within a week or so, however.

 

Trying to track down a boost problem. The car will only boost to about 16 psi - Everything appears to be hooked up correctly and all the intake tubing and hoses seem to be holding fine. It looks like I may need to do some vaccum circut testing.

 

Alright- it looks I've got the boost problem fixed. I've got dyno time booked for tomorrow morning with Ron at RS Motors and we'll see what the car does.

 

where was the leak?

 

It wasn't a leak, it was related to my initial attempt to hold more boost. My second method worked much better, and the car is now capable of holding a small bit more boost.

Unfortunately the new HKS 280s don't seem to work well in my car at all; When I hit the dyno late Saturday, I dropped 35 whp and 15 lbs of torque from the run posted above with my Pipers. I'm in the middle of re-installing my Pipers right now to head back to the dyno for a back-to-back test. I'll keep the same cam timing and boost, but will adjust the AFRs as needed.

I guess we'll see what happens...

 

Warning- Please forgive the this post if it seems to be negative. BUT it is not. Just a slight comparison.

We have a similar dyno in the Mustang just the newer gen. We just finished a car two days ago with just basic mods, including Buschur FMIC kit and 272 HKS cams.
Boost was 24 psi and tapered to 17 psi at 7000 rpm. The car was tuned with an AEM and nothing else. 325WHP and 325 WTRQ
Again this is just a slight comparision with the dynos. Your numbers do not seem right to me at all. Please let us know how you make out. You have an intersting issue and I am wondering if it is a tuning issue or the hardware being used to tune with.

 

No offense taken. I'm all for straight information without agends.

The numbers seemed really low to me as well. My car had put down 292 whp with just the Piper Rally cams and a 3" full exhaust before the ported head, 10.5 hotside and and HKS 280s. At the time my car was peaking to 23 lbs and then doing a flat taper to 17 lbs of boost. Seeing 310 on a bad head gasket seemed reasonable as I figured the 10.5 hotside and the head work should be worth more than 18 whp.

I have the Pipers back in the car with the cam timing set to match the -2/-2 timing I used with the HKS cams. The car feels more responsive and definitely has more low rpm driveability. It also feels like there is good power to be had by re-tuning the maps - the mid-range is missing slightly under full load and the top end sounds too tinny.

Later this week I will be putting the car back on the dyno and adjusting only the fuel curve to match the settings I used with the HKS cams - it will be an honest back-to-back comparison. I'm really interested in seeing how everything works out. One posibility is that the head porting I have just likes the high lift and steep ramp of the Piper cams better than the HKS configuration.

I do know the dyno isn't whacked; earlier that same day I watched a stock Evo MR put down 220 whp.

 

Are you using the Piper cam gears? I remember reading on MLR that the Pipers use a different pin position on the cams which can really screw w/ your results w/ the HKS 280's.

Also, you can't trust results from dyno to dyno. Hopefully, Precision dyno understands that. I do find it interesting that your torque curve is so flat. It looks like you tuned out the boost spike really well. Have you installed the pressure bleeder that Vishnu uses?

 

The top set of charts was with with the Pipers set to 0/0 and no boost bleeder. I will post up both the HKS and Piper charts after I get back from the dyno - hopefully tomorrow or Wednesday. For the new charts I will be comparing I am using a modified bleeder and my Pipers are set to -4 Intake/+1 Exhaust. This should be equal to -2/-2 on a set of HKS cams - the same settings I used when I dynoed them. The cam gears I'm using are from Vishnu.

I owe Ted B a big thanks for mashing the details of of Piper vs HKS cam timing into my over-tired brain. I was so sleep deprived from work that I made him repeat himself .. alot .. before I finally got it.

 

Yes I understand that the numbers will vary , but vary very little from Mustang to Mustang. It isn' t the peak numbers I am concerned with. It is the Gap between peak torque and hp in relation to cam timing that is stated above. He has a nice setup and I was interested in knowing how he made out.

 

I will be hitting the dyno (again) about 10 AM this morning. The first order of business will be to dial in the AFRs and replicate my HKS cam runs with my Pipers cams re-installed to provide some idea of the differences. The cams are the only change on the car so it should be a good back-to-back comparison.

After that I'm going to try some things to limit my boost taper some and see what kind of performance that will provide. My 3rd goal is to try out some different cam timing settings to see what my car likes best. Hopefully everything will go well!