Well, I finally got the truck back this Wednesday form new IC. Have been driving and weather is great so I took it to finally get dyno done. I was the 5th Gen 2 L this place has done; about 25 - 30 pulls ahead of me have been recorded. My first run netted only 315.5hp and 402.9lb torque. I was a little disappointed at the numbers but the really bad thing is this ungodly spike in the curve at about 4300rpm. I actually saw the RPM needle on the computer flutter at his range. So we did another 2 pulls and the exact same thing. We then ran through almost all the other dyno graphs and not a one of them came close to mine. The gentlemen said it felt like it was slipping in the shifts on the dyno as well. I thought I had noticed a slip when I first got it, but I guess I have grown use to it and dismissed it since then. So what to do now? I took it to my uncle who builds race car engines for outlaws and older muscle cars. He drove it and really worked the truck and said it seemed to slip under hard acceleration at around 3500rpm and 4200rpm.

So guys I am asking for any expert ideas, guesses, prayers or anything. I am planning on visiting Sami again Monday at the dealership but wouldn't mind hearing someone else had this same trouble and got it fixed.

Thanks in advance.

Eric

 

My dyno runs do the exact same thing, I get the spike at 367 foot pounds.

If you look at my dyno runs it happens all over the place because of all the dyno runs with different mods.

Stock it happens at 4300 rpms and with a chip and MAF at 3700 rpms, both times at 367 foot pounds.

That's when the torque converter locks up and fools the dyno into thinking that you're making more hp than you really are. I don't fully understand it, but thats the explanation from my dyno pilot.


[This message has been edited by lgogether (edited 03-24-2001).]

 

Yeam the dyno pilot said the same thing here but they also believe as do I that this isnt correct. The converter should lock in way before that, as is aparent by the other stcok dyno graphs we compared mine too. I am fairly sure that my converter is meesing up and have the other mechanics think, I am just hoping I can convince Ford of this too.

Eric

 

Mister SVT,

There are a couple of different dyno types, but if yours is like mine (with a lot of resolution) you're just seeing the converter lock up.

There are a ton of dyno runs around the internet that show the same thing, just be sure that you're looking at one created with an automatic transmission. BTW I have had 2 different L transmissions and when they let go you'll know, both had the converter lock up spike also.

Search around this forum and you'll see the spike in other dyno runs. Be sure that it's a high-resolution run, or you'll see 1st, 2nd, and 3rd gear on one plot. Looks like a big wave, others have confused the transmission shift points as converter lockup on this type of run.

Below is a dyno run with spikes in mine, this never works?

 

Thanks for your time and info on this. The dyno graphs were from stock 99 and 00 L the y had run on their dyno, the same I just ran on. I wouldnt have thought much of it tho if they hadnt said they noticed a slipping and then my uncle, who also builds race cars and outlaw engines, said he noticed a slipping.

I was just curious if any else had trouble with a slipping and have/had that replaced.

Eric