hey guys. I finally got internet and back online. Just saying hi to the folks that know me. Hey Vincent!

My hi flow cats have gone out and I'm just going cut them out. I felt that i have lost some torque since i installed the hi-flows from lack of back pressure. Would adding a bigger pulley help with lost or should i just stidk with a 4 pound? was thinking about going with a 6 or 8.

later

 

NateTrun2 - do you have a build lower or build motor??? running a 6 or 8# with a 100 shot = BOOM....????

 

no, i think its an 03 block with 02 heads in an 02 truck. Or it could be just an 02 block. stock bottom end. it handled whats i had to over 140 on nitrous running it for around 5 - 10 minutes full thottle. it did burn up some of my plugs though. they weren't cold enough. now i just have the motorcraft from the dealership. hrmmm...but i am wondering if i should even get a bigger pulley. on motor this winter i'm probably making 390 to the wheels. when i ran it that hard in the summer i was pushing around 470 to 475 to the wheels on nitrous. The re-flash though is pretty tame... and with the exhaust setup i lost some hp and tq...pretty sure of it. so im just thinking why not compensate with a little more boost and running the mild flash.

 

Nate, how is Arkansas? I am getting a 4lb should be here in a few days. I am glad to see that you got the transmission problem sourted out. With the lost of back pressure how much boost are you seeing?

 

Think of an engine as an air pump, the more air that flows through it, the more power is made.

Increasing backpressure is counter productive to this.

 

back pressure is essential for low rpm power. like on a launch...higher speeds do not require back pressure. if you have ported heads then you have more flow. i think street production vehicles need back pressure. i'm only going by my dyno numbers and my truck...I still know of some people running stock cats and lost hp like i did from high flows.

hey vincent...i'm not sure on how much boost I'm running exactly. I don't have a boost gauge and don't plan on running one. I'm just going by my base hp and what I want it to be. I remember i think i made 375 rwhp on the bad dyno this last summer...so, maybe 380 or 385 ...maybe... i would like to see 400 hp on that flash with a bigger pulley...so why not more boost...


I burned up my plugs with the nitrous and thats the only problem i had. no tranny problems . how are you doing? arkansas is nice...but can't get a good job..

 

Hang in there, tell Kelly we said hello. When you coming to visit?

 

Nate, Welcome back, I had wondered what happen to you. I see you say that you have a 03 Block with 02 Heads Does that mean that in this post https://www.f150online.com/forums/sh...hreadid=124673 your motor was toasted after all ? If so I assume Team Reflash saved you when the dealer checked for a chip and you simply removed all your mods

 

hehe. thanx Vince. Man, soot me you phone number and email. sorry. my connection went out when i was about to ask that.


hey bigfan
its a long story about the dealership. but i paid them to change my plugs. They checked out my computer and reset my KAM.The only problem were burnt up tr6's. They weren't cold enough. Should have ran br7's i guess. .their was no damage to the motor. my block doesnt have a date sticker on there. At the dealership they gave me a service record of my truck and it showed that a new motor was put in at 4,000 miles. i bought it with 4,000 miles on it from the dealership, so heh.... i guess with a fresh motor. whoever owned it previously must have tortured it.

 

That is only part of the picture and only applies to high rpm situations. At lower rpms cylinder scavaging is very important. And this backpressure is the key to it.

It's all a balancing act though. Do you want to maximize low/mid range torque, like for purley street driving? Or just maximize high rpm hp (torque) for all out racing? Or do we want to fall in-between somewhere? This becomes more and more appearant on our SC motors too. More so than a NA motor.

Anyone whos messed around with tuning 2 cycles will know what I'm talking about. Just by changing the backpressure you can tune where the sweet spot is in your torque curve.

Rich B

 

when I replaced my high flow cats with um, pipes without kittens in them... I actually saw a little increase in boost...

No problem though!

BTW: Nate, I sent you an email! Visit the ARLOC forum under the local clubs on the nloc.net