Losing power

[justbob]

I have been on the dyno three times in 2 1/2 years, all dynojets, and keep getting lower numbers.

First tune: 2 1/2 years ago, Kurgan. 49* and rain, she made 445 11.4 boost

Second: just a Dyno day at Deans Performance about six months ago. Probably 80* sunny, very low humidity, she mustered a lowsy 428?? (No other mods done since last) 10.5 or so boost.

Third: Last September at Mr. Norms Garage and only to verify my AFR from the work I had done and a possible detune (so I thought..) 85 and not a cloud in the sky. And a WTF! 409 at just under 10 pounds boost. This is after I fabbed up MAC long tubes, ditched the kitties, and fabbed a 2 1/2" system to the tail pipes (X pipe and Magnaflows), and I also scrapped the stock zip tube finally and installed a JLT for now.

Tim Barth raised a good point that the more free flowing exhaust robbed me of a pound or so of boost, plus major difference in temps. He did not have an answer as to why my new exhaust didn't make some good power though? Everything looked beautifull in the tune and he just said take it to the track and I might be surprised. So I did, I ran it twice, at 85* and this is where it gets interesting.

First run on street tires blazing up the pavement, let completely off and pound it again I got a 1.80 in the 60, second time with stickies another 1.80 with either bad wheel spin or she pulled timing, I honestly couldn't tell. Here's the kicker. My best EVER with COLD temps, stickies that stuck like glue, 1.76! A couple short weeks later I fried my clutches, so could these clutches have killed power in any way on the dyno??

I have now scratched THIRD gear TWICE. She has never even contiplated that before. This new set up pulls HARD and doesn't let back down at all, any speed. It feels like a centri has kicked in. So?? Torque converter? Trans? Clutches? Where could it be hanging up at? The boost drop I get, but not the H.P. I don't even know what to say anymore when asked about numbers...

[guspech750]

Hey. You and I will go over to Deans soon and have ourselves a dyno day. See what the numbers are and see if Hans has anything to suggest if need be. :burnout:

I think some of the power loss is possible just from different people running the dynos.
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Eaton Swap + 4.10's = Wreeeeeeeeeedom!!

[DOOM]

That's weird Biscuits

When I. Put on my KOOKS I went from 425RWHP to 473RWHP!!! without changing a damn thing on the tune! I actually had them cut it back to 460RWHP because I was on my stock motor at the time.

Never heard of anyone losing power AFTER installing headers!

Maybe time for a blower rebuild!

[boatmangc]

Interesting that your boost went down each pull, the second pull you lost .9 psi and had made no changes.
Maybe belt slippage?

[Bradley G]

The stock tensioner is no match for your set-up now.I know I need one too.
Lonnie sells one that will keep you from losing power on top.

[Black&Gifted]

I understand the difference in power and boost between the first and second dyno runs. 30 degrees in air temp makes a huge difference. However, the second to third dyno pulls really makes no sense. Sounds like she is a beast on the 1360....that's really all that matters.

could it be just be that each dyno is set up a bit differently (not sure what my numbers looked like from different dynos but I'd have to look at old dyno sheets to see)?!?!?!?!

as for if people ask about numbers, I'd go with "its stock...pinks?"

[justbob]

Hey. You and I will go over to Deans soon and have ourselves a dyno day. See what the numbers are and see if Hans has anything to suggest if need be. :burnout:

I think some of the power loss is possible just from different people running the dynos.
---
- Sent from my iPhone
Eaton Swap + 4.10's = Wreeeeeeeeeedom!!

Yeah, I'm thinking this needs to happen. Maybe bring my 2.8 pulley along as well. Still thinking about getting the T posi ported as well over the winter, building a cornfed fuel system, along with a snow system. Might be time to drop in the cobra block, but I would really like to not put the mileage on it as it will be quite awile before I can fork over the cash for the 4.0 whipple, trans and converter. This whole next step in power is EXPENSIVE! I am just wanting to run with the stock engine for as long as I can, but not hurt it as it is a STRONG and healthy little 4.6 and would make for an awesome 4.6 Trilogy motor for a newer Explorer family car!

I really need to get back to the track on a cool night and get her to stick so I can compare numbers. Dyno is one thing, real world is another.

[Krytin]

After doing a complete overhaul on my rear axle I would like to sugest that IF you have the car up in the air AND you want to pull the drive shaft just to give it a close once-over, try turning the pinion yoke by hand. I couldn't believe how f'ed up the bearings were in mine when I did this before we opened it up! I had to have lost (over time) and regained 10 rwhp!!

[guspech750]

Yeah, I'm thinking this needs to happen. Maybe bring my 2.8 pulley along as well. Still thinking about getting the T posi ported as well over the winter, building a cornfed fuel system, along with a snow system. Might be time to drop in the cobra block, but I would really like to not put the mileage on it as it will be quite awile before I can fork over the cash for the 4.0 whipple, trans and converter. This whole next step in power is EXPENSIVE! I am just wanting to run with the stock engine for as long as I can, but not hurt it as it is a STRONG and healthy little 4.6 and would make for an awesome 4.6 Trilogy motor for a newer Explorer family car!

I really need to get back to the track on a cool night and get her to stick so I can compare numbers. Dyno is one thing, real world is another.

Wooooooo hoooooooo!! Lets tear that sh$t out man. Like as of last month!!


---
- Sent from my iPhone
Eaton Swap + 4.10's = Wreeeeeeeeeedom!!

[Da Dark Jedi]

Hey JB, didn't they make a song about you??? I think it's called "Life in the Fast Lane"!

[justbob]

Hey JB, didn't they make a song about you??? I think it's called "Life in the Fast Lane"!

Video response from JB. NWS!
http://www.youtube.com/watch?v=gN3KLL64mkI&feature=youtube_gdata_player

[DOOM]

Blower belt.

How much play does your belt have?

[sailsmen]

There are too many variables in the 1320 to make a comparison. Are you Standard or SAE? Can you post the Dyno Graphs?

[flyin_hawaiin]

3 things come to mind..

#1 belt stretch... belts are made of rubber and eventually stretch over time... replace it
#2 tensioner spring losing tension!!
#3 lockup... when i tuned the car on the dyno, i can LOCK THE CAR IN GEAR and lock the converter... when you try and dyno an auto car without locking it, the converter will not always lock..

[justbob]

Blower belt.

How much play does your belt have?
The tensioner is near max but hasn't yet slipped (that you could tell) on the dyno. It does squeal every now and then when I let off. Belt is a hair too long.






There are too many variables in the 1320 to make a comparison. Are you Standard or SAE? Can you post the Dyno Graphs?

SAE IIRC I unfortionately am very bad with paperwork... Let me see if I can dig up the first two. I left without a copy on the third. I agree on the variables, but know the local tracks very well and even moreso know this car like the back of my hand. I know in the first 6" what numbers I will make.





3 things come to mind..

#1 belt stretch... belts are made of rubber and eventually stretch over time... replace it
#2 tensioner spring losing tension!!
#3 lockup... when i tuned the car on the dyno, i can LOCK THE CAR IN GEAR and lock the converter... when you try and dyno an auto car without locking it, the converter will not always lock..
Thanks for stopping in Bob. Heard your coming to town the same timeframe this black money pit will be in getting new 31's and a gear at Deans. Maybe a coincidence?;)

Belt is a green gates and fairly new, but I agree on the tensioner. It is probably about 6 years old with 60,000 miles. Could slippage and a drop of only 2 pounds or less of boost cause this though? I should have been going in for a detune after the LT's, X, and CAI.

I realize weather and a different dyno will always dictate a different number but damn, 36 RWHP loss AFTER exhaust and CAI? I didn't want to even talk about it at first, but I am ready to get this girl back into shape.

[Vortech347]

Depending on the mileage the rings could be wearing out and allowing excessive blow-by.

[flyin_hawaiin]

The tensioner is near max but hasn't yet slipped (that you could tell) on the dyno. It does squeal every now and then when I let off. Belt is a hair too long.







SAE IIRC I unfortionately am very bad with paperwork... Let me see if I can dig up the first two. I left without a copy on the third. I agree on the variables, but know the local tracks very well and even moreso know this car like the back of my hand. I know in the first 6" what numbers I will make.





Thanks for stopping in Bob. Heard your coming to town the same timeframe this black money pit will be in getting new 31's and a gear at Deans. Maybe a coincidence?;)

Belt is a green gates and fairly new, but I agree on the tensioner. It is probably about 6 years old with 60,000 miles. Could slippage and a drop of only 2 pounds or less of boost cause this though? I should have been going in for a detune after the LT's, X, and CAI.

I realize weather and a different dyno will always dictate a different number but damn, 36 RWHP loss AFTER exhaust and CAI? I didn't want to even talk about it at first, but I am ready to get this girl back into shape.

ive seen a slipping belt lose 15psi on a 30psi setup....

remember, each psi is TYPICALLY good for about 15rwhp.... 2psi x 15psi = 30HP

[justbob]

Good info, thanks.

What do you think of this one? It is the only listiing that specifically says Trilogy Marauder, although it appears that it also fits the accessory serpentine on 03-04 Cobra's.

http://www.blueovalchips.com/index.php?l=product_detail&p=311

Only problem is it claims good for 500 RWHP and I plan to exceed that number by around 50 horsies very soon.

[sailsmen]

I have a Thump and so far so good. I have only heard positive things about them.

Only that model has an HP Limit. I would contact Peter Mitas @Thump Racing.

[justbob]

I have a Thump and so far so good. I have only heard positive things about them.

Only that model has an HP Limit. I would contact Peter Mitas @Thump Racing.

Just sent email. Thanks Sailsmen.