New Remanufactured Engine low on Power? Can you help?

[Banshee06]

I had bought a KB 2.8H LC and had it installed on my 03 Cobra with about 48,000 miles on it.
I had it dyno tuned on a Mustang Dyno and it put out 605 rwhp and 541 tq and It was Crazy Fast.

I had to buy a new motor because it stopped getting oil to the head on the drivers side and caused the cams to freeze and broke the timing chain

So I bought a Remanufactured long block from Ford.
Then I went and had this motor dyno tuned.

This motor only puts out 584 rwhp and 524 tq on a DynoJet dyno which should show more than the Mustang Dyno.

You can feel that this new motor with everything else the same is lacking the horsepower that is had with the old motor.

Do you have any ideas why this would happen.
It had about 3500 miles on it when I had it Dynoed and currently has about 8500 on it.
Ford installed the motor and reinstalled the supercharger and everything else.

PS and it is still putting out 20.5 lbs. of Boost.

 

[s351]

What fuel are you running 20.5 pounds of boost is a lot for pump gas??

And lots of things can contribute to a slightly low reading dyno. You went from 605 to 584 which isn't really a lot. Different temp, different day, different dyno... Lots of factors.

If your on a stock motor, with stock heads and cams, 20+ psi is a lot on pump gas I bet you make the same on 18 psi, with more timing.

 

[masterjr33]

ill guess.
wrong heads . no the real 03-04 cobra heads .

or you got bad/unlucky cam timing.and now you have a 20/20 cobra.

 

[Banshee06]

I am running NOS racing octane booster 1 can per tank
Same as before the car is down about 80 rwhp from before the Dyno jet should have my car at 650 rwhp.

 

[Banshee06]

20 20 Cobra??
Can the cam timing be checked or changed?

 

[s351]

Remember there are low reading dynojets, don't just think because it's a dynojet its gonna make up 45whp.

Have you done your compression test and leak down? that's pretty much the first thing to check.

 

[Banshee06]

And I can feel the difference in power it's more like when I had my ported Eaton now..

 

[s351]

Did you get it re tuned?

 

[Banshee06]

Yes car has been retuned
Since it is a new motor I haven't had a compression check done and I have no idea what a leak test is or who could do one

 

[s351]

A leak down test basically tells you how well your pistons/rings are sealing, or how much blow by, you have. It's a similar process to a compression test, they usually go hand in hand.

 

[s351]

For example, I had my car tuned once, after a fuel system upgrade. When I was supercharged, I made 514rwhp, after the retune it only made 437rwhp.

Took it to a different shop, got a leak down test done, and I had 80% blow by, on 4 of my pistons and 60% on the other 4. All my pistons where melted, my heads were screwed. I'm not trying to scare you just giving you advice.

 

[Banshee06]

Oh okay well its run the same since the motor was new and after break in it hasn't gotten any stronger

 

[MG0h3]

Im doing the math and its 21 RWHP difference........EDIT: Saw your sig numbers of 650rwhp. Guessing the 605 in your initial post was a typo.

Were in the dead of summer, so the heat could easily do it.

I know my car feels totally different in the winter vs summer so that may be what you are feeling? Not sure what time of year the first dyno was done. Like others said, the dyno could be difference in numbers.


What surprised me more is your HP vs boost on either engine. My car made 590 on 15 psi which is pretty normal. Most cars in your boost range should be upper 600s I would think.

 

[s351]

Im doing the math and its 21 RWHP difference........

Were in the dead of summer, so the heat could easily do it.

I know my car feels totally different in the winter vs summer so that may be what you are feeling? Not sure what time of year the first dyno was done. Like others said, the dyno could be difference in numbers.


What surprised me more is your HP vs boost on either engine. My car made 590 on 15 psi which is pretty normal. Most cars in your boost range should be upper 600s I would think.

This is why I said why are you running 20+ pounds of boost there has to be absolutely 0 timing in it. I would be running 17/18 pounds with way more timing and making the same if not more power. I tried explaining the hp difference do to weather and different dyno's. He needs to do a compression test and leak down if he thinks hes low on power.

 

[Banshee06]

This car did put out 660 rwhp (mustang dyno 605+ %10 = Dyno jet rwhp approx)
Now makes 584 rwhp

 

[s351]

^^^^^^ This is where you are misguided. Not every dynojet reads 10% higher. Guys have gone from a mustang dyno, to dynojet and make the exact same amount or less. Usually dynojets read higher but it's not always the case. A dyno is a tool and can be made to read whatever a person wants it to. 605 on a mustang dyno means it made 605. Until you find a dyno that reads 660, your car makes 605.

 

[Banshee06]

Kenne Bell just sent me an email saying it looks like the new motor is way down on power also

 

[s351]

That's because your telling them it made 660! when it never has. If you told them your car made 605 and then 584, 21rwhp a hot day could do that. I've tried to help you, your first step is checking the compression and then doing a leak down to see if your motor is hurt in anyway. After that it's your tune running 20+ on pump gas with octane booster still isn't that great. On 18 psi you should be in the 590-625 range. I can almost guarantee ur tune has zero timing in it because your running so much boost with poor fuel.

 

[Riddick]

Who tuned your car? Was it the same person that tuned it before? Also, do you know how much timing you are running or what your A/F ratio is (your old tune vs new tune). Your numbers really dont seem all that low, you could have a tune on your car that is running low timing since you are on pump gas and it could be running rich as well.

If you suspect something in the motor get a compression test done at a minimum. If a cylinder reads low then do a leak down test. You can pick up a compression tester fairly cheap and if you can change spark plugs you can do a compression test.

Please dont go off dyno numbers aloe, THEY ARE JUST NUMBERS and mean nothing.

 

[Banshee06]

That's because your telling them it made 660! when it never has. If you told them your car made 605 and then 584, 21rwhp a hot day could do that. I've tried to help you, your first step is checking the compression and then doing a leak down to see if your motor is hurt in anyway. After that it's your tune running 20+ on pump gas with octane booster still isn't that great. On 18 psi you should be in the 590-625 range. I can almost guarantee ur tune has zero timing in it because your running so much boost with poor fuel.

No your wrong here is my email to Kenne Bell

I had bought a KB 2.8H LC from you and had it installed on my 03 Cobra with about 48,000 miles on it.
I had it dyno tuned on a Mustang Dyno and it put out 605 rwhp and 580 tq.
I had to buy a new motor because it stopped getting oil to the head on the drivers side and caused the cams to freeze and broke the timing chain
So I bought a Remanufactured long block from Ford.
Then I went and had this motor dyno tuned.
This motor only puts out 580 rwhp and 540tq on a DynoJet dyno.

You can feel that this new motor with everything else the same is lacking the horsepower that is had with the old motor.
Do you have any ideas why this would happen.
It had about 3500 miles on it when I had it Dynoed and currently has about 8500 on it.
Ford installed the motor and reinstalled the supercharger and everything else.

here is his answer:
Same tuner both times? The new more is WAY down on power, Mustang Dyno’s read a lot lower of a # than a Dynojet. Compression ratio, timing etc. The only thing that was changed is the engine?