I took my truck in to get dyno tuned yesterday, this is the first time this has been done on my truck. I had my truck on they dyno a few weeks ago and it put down 219 horsepower with my vortech but I did not get it tuned at that shop. Since then I put in an electric fan and the base run yesterday put down only 219 horsepower. I got everything tweaked shift points firmed up and picked up about 17 horespower with the tune but I still only made 233 horsepower. I do not understand? I have the 5.4 V8 with vortech supercharger. I really need some advice here!?

The only thing the tuner suggested is that my CATs might be plugged and they may have melted down since my truck wasn't tuned properly. He also said I was making anywhere from 10 to 11 pounds of boost yet I my stock vortech pulley is supposed to be 7-8 psi and the higher boost could be back pressure from a restricted exhaust. He did the pulls in 2nd gear because he didn't want my tires spinning too fast on the dyno being 35's he said it could be unstable. I have the stock gears in as of right now if that makes a difference. I just would have expected over 300 rwhp with my setup.

I highlighted my lines because they are hard to see. Green was base run 219 HP 262 torque. Blue was final tune 233 HP torque 274

 

second gear would mean more torque and less adjusted HP

put some factory wheels on and run it in 3rd

 

Where are you measuring boost at?

You have to have something MAJORLY wrong....

Plugged cats might could cause that, but still...dang...

at 12psi i was making 450rwhp on a very conservative tune...

 

they had it hooked up on the vaccum line where i supose it would normally be hooked in at under the hood. It doesn't make much sense to me. He said he had a built mustang with something like that happen once and they pulled the exhaust off and horsepower went from 350 to over 500 so I hope it's that simple.

I don't know much about exhausts and I don't think there are any shops that will just take my cats out for legal purposes so I guess I better start reading up on what to do.

 

Ask the guy that tuned your truck where to go that is "friendly".

 

buy some magnaflow Highflow cats then go to the exhaust shop and tell em to put them on.

 

I dunno I've delt with quite a few clogged cats and after driving a while they will go gutless and fall on their face. I would be more inclinde to think you have a vac/boost leak some where

 

I should have mentioned that when I ran it the first time on the dyno a few weeks ago I had a boost leak test done and it held 20 pounds with no trouble.

 

Lightnings run the same cats as NA, so a functioning cat is not the problem. Now if your cats are clogged thats a differnet story, but then you should be getting a CEL!!!

 

well I can personally say that my vortech setup clogged one of my cats and blew out the other and caused my truck to do funny things...

There is a thread about it on this forum somewhere...

edit: https://www.f150online.com/forums/20...tock-cats.html

 

Would agree that the "setup" could have done bad things to the cats. The combination of parts and the tune can have catatrospic effects on everything.

 

what gears are in the truck?

with the 35's you aren't going to dyno the same as someone with a 28-30 inch tire, take a alook at z7what's truck, he's got the same mods and many lightnings and he consistantly dyno's less power same eufrin's truck

 

this might have something do with it


https://www.f150online.com/forums/su...aking-oil.html

 

I wouldn't fully agree with that, im on 35's and 9 lbs and dyno out at about 385/450...

The thing with z7w is he tire and wheel combo are much much heaver then a stock lighting.. Most stock 04-08 truck come with a 32-33 tire stock so 2"s more wont be a big difference unless weight is dramatically increased. But even so, im rolling around on a 135-140 combo per wheel and tire and my numbers are significantly higher.

 

Few questions, maybe i missed it but:

What year truck?
How many miles?
What was the A/F?
What was the Timing?
What were your IAT2?
what was weather like that day?