Disappointing dyno results
That was my thought too on transmission/converter slip but when I posed that question to my tuner his thoughts were if the trans was slipping the numbers would progressively get worse - which they were not.
It is possible the tires are spinning- I will bring that up to him today.
It is possible the tires are spinning- I will bring that up to him today.
If it's using 1000+ hp worth of fuel/air then it has to be drive line related. How was this calculated? Injector duty cycle? MAF flow? Seems really strange the dyno operator couldn't have pointed you in that direction, then verified what the converter was seeing slippage wise on the dyno.
Thread Starter
Staging Lane
Joined: Sep 2012
Posts: 79
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From: Saint Petersburg, FL
If on any of the pulls he has a mph reading and an rpm reading from the dyno it would be easy to tell if trans was slipping or converter was to loose. We have had to put people in the trunk on cars so they didn't spin. We have even used the chute mount and pulled the rear of the car down to the dyno with a strap to get traction.
Thread Starter
Staging Lane
Joined: Sep 2012
Posts: 79
Likes: 0
From: Saint Petersburg, FL
If it's using 1000+ hp worth of fuel/air then it has to be drive line related. How was this calculated? Injector duty cycle? MAF flow? Seems really strange the dyno operator couldn't have pointed you in that direction, then verified what the converter was seeing slippage wise on the dyno.
A/F was pretty much 11:1 on boost, timing was 10* and around 4600-6800rpm's detected some spark knock so he pulled 2* out and that solved it with measly 14psi boost.
Thread Starter
Staging Lane
Joined: Sep 2012
Posts: 79
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From: Saint Petersburg, FL
We haven't done a compression test nor pulled the plugs as of yet - I will check the plugs tomorrow. It is a fresh built motor, engine was broken in prior to Dyno testing, oil/filter changed. Cam was degree'd in by Nelson Competition.
9 Second Club
Joined: Nov 2003
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From: Norn Iron
Those turbos are bound to be screaming their **** off trying to make 1100hp or so on a motor that size, especially on pump
When you say dyno wheel speed matches output shaft speed, are they also in sync with engine rpm ? ie no slippage anywhere ?
What camshaft is in it ?
If the engine had been working great until it went bang, why were so many changes made ? What was actually wrong with it when it made decent power ?
Is it being tested on the same dyno ?
On the road, does it drive like 600hp or 1000hp....that would be an easy giveaway.
When you say dyno wheel speed matches output shaft speed, are they also in sync with engine rpm ? ie no slippage anywhere ?
What camshaft is in it ?
If the engine had been working great until it went bang, why were so many changes made ? What was actually wrong with it when it made decent power ?
Is it being tested on the same dyno ?
On the road, does it drive like 600hp or 1000hp....that would be an easy giveaway.
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TECH Fanatic
Joined: Jun 2013
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From: Avon, Ohio
That was my thought too on transmission/converter slip but when I posed that question to my tuner his thoughts were if the trans was slipping the numbers would progressively get worse - which they were not.
It is possible the tires are spinning- I will bring that up to him today.
It is possible the tires are spinning- I will bring that up to him today.
You would know if the wheels where spinning. I short-unless the tires are wet or the roller is polished smooth you should not be spinning at 650 whp.
If the tuner is sure it has timing in it-I'm going to go with F'd cam timing. Most times I see "motor runs great but stops making power" its the cam.
Thread Starter
Staging Lane
Joined: Sep 2012
Posts: 79
Likes: 0
From: Saint Petersburg, FL
Those turbos are bound to be screaming their **** off trying to make 1100hp or so on a motor that size, especially on pump
When you say dyno wheel speed matches output shaft speed, are they also in sync with engine rpm ? ie no slippage anywhere ?
What camshaft is in it ?
If the engine had been working great until it went bang, why were so many changes made ? What was actually wrong with it when it made decent power ?
Is it being tested on the same dyno ?
On the road, does it drive like 600hp or 1000hp....that would be an easy giveaway.
When you say dyno wheel speed matches output shaft speed, are they also in sync with engine rpm ? ie no slippage anywhere ?
What camshaft is in it ?
If the engine had been working great until it went bang, why were so many changes made ? What was actually wrong with it when it made decent power ?
Is it being tested on the same dyno ?
On the road, does it drive like 600hp or 1000hp....that would be an easy giveaway.
I'm answering what I was told by my tuner. Again he's a noted tuner around here and has experience with high horsepower forced induction setups so I trust what he tells me.
I don't know what camshaft is in it. The motor was built by another reputable race engine builder - Nelson Competition of St. Petersburg, FL. I will have to get the specs from them.
We changed the fuel plumbing and re-engineered the headers, turbo setup/piping because the shop before had no clue what they were doing. I'm not trying to slam the other shop as that's not my intention but had anyone of you had done on your own car what was done to this customer by said shop - you would want to shoot the f&€ker. Let's just say it was **** poorly designed turbo system and the customer got taken for huge amount of money. Other than reduing the fuel system, headers - turbo piping, radiator and new Pistons & rings (same compression as before) everything else stayed the same - same transmission, convertor, 22" wheels, turbos, wastegates, blow off valve, intercooler.
No it's not being tested on same Dyno / tuner. I'm aware of the variances of different Dyno's and how one will give you xxx amount and the guy across the street will read another but not 200hp different.. Also if you saw the abomination that was originally setup in here that put out 800whp and what's in here now you would be pulling your hair out as I am.
No the car hasn't been street driven yet. I wanted to get the motor broken in, tuned before we drove it and I still have a couple more things to finish once the tune is wrapped up.
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From: Scottsdale, AZ
I just don't believe 14# is going to make more than that through an auto. You need more boost. I'm guessing 18# will give you around 850rwhp or so and 20+ to hit 1k wheel. A little different setup but my old 427LS7 took 22psi through a 6-speed for 1072rwhp for example. Add a converter and you're looking at ~800 tire?
He said according to the amount of air being ingested + fuel consumption - the math equated to roughly 1100hp but didn't say that's what the motor was actually making. He didn't say the convertor was slipping. We're both stumped as we know the combination & engineering from what it was to what it is should be significantly more than 650whp..
A/F was pretty much 11:1 on boost, timing was 10* and around 4600-6800rpm's detected some spark knock so he pulled 2* out and that solved it with measly 14psi boost.
A/F was pretty much 11:1 on boost, timing was 10* and around 4600-6800rpm's detected some spark knock so he pulled 2* out and that solved it with measly 14psi boost.
I understand that your running pump gas and pulled a little timing out because of some spark knock but 10 degrees of timing still seems pretty low for 14psi. Seems like that could be were your loosing some of your power. Maybe you got some bad fuel?
9 Second Club
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From: Norn Iron
Really there are so many variables here. Without actually driving it before and after to see if it genuinely is heavily down on power, everything else is pissing in the wind.
I know the dyno should be some sort of indicator, but it just sounds like an impossibly low figure for the amount of boost ( compared to some other numbers flying about the forums...but then some of them you could say were dubiously high ).
Surely the tuner has some thoughts themselves ? They have all the info to hand and can feel what the motor/car is doing when under load etc ?
For it to be so down on power, the engine must be exhibiting some other strange behaviours too ?
I know the dyno should be some sort of indicator, but it just sounds like an impossibly low figure for the amount of boost ( compared to some other numbers flying about the forums...but then some of them you could say were dubiously high ).
Surely the tuner has some thoughts themselves ? They have all the info to hand and can feel what the motor/car is doing when under load etc ?
For it to be so down on power, the engine must be exhibiting some other strange behaviours too ?
Do a compression test and give all the plugs a good inspection. Get the exact specs on the heads, compression, cam. Even at 8.5:1 I'd think A 427 with decent head/cam should be making 550+ at the crank. At 15-16lbs it should double that if it's not out of turbo. Minus 15% or so for driveline losses. You're down a ton of power. Ask your tuner what math he used to get his 1150 chp figure.
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Joined: Jun 2013
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From: Avon, Ohio
TECH Fanatic
Joined: Jun 2013
Posts: 1,163
Likes: 16
From: Avon, Ohio
