Engine/Transmission (1998.5 - 2002) 2700RPM defuel??

[Wyatt 1]

Can anbody tell me what this feels like, I think it happened to me but I was paying more attention to the fuel and boost and egt to look at the tach, but I saw 40psi and it started cutting out, maybe the 2700rpm defuel?? Didthird and fourth, box was on 4-4. Henry

 

[ToolManTimTaylor]

Which truck? The 02 or 99

 

[Devan Manis]

If you watch your boost gauge if and when it does it your boost should start to drop off.



On edit: It shouldn't start to just cut out like when a gasser hits the rev limiter they should just cut back the fuel so there will be less power.

 

[Double J]

My hesitation feels like a delayed shift and I always thought it was my transmission but I guess it was just the defueling. It's not going to totally fall on it's face, but like I said... a delayed shift. I watched my boost go from 40psi to 30psi during that delay also, if that helps. I'm anxious to see what kind of a difference a drag comp will make at the track vs the regular comp. I'll know on the 31st

 

[Wyatt 1]

Which truck? The 02 or 99

It was on the 02.

Had the box on 4-4, I know if I would have had it on 5-5 it would not defuel above 2700, but I found that out after the fact.



I think that is the only difference between comp and drag, no defueling above 2700rpm, ..... I think, that could be my first mistake,

 

[Wyatt 1]

Double J,



This was a noticeable difference, did it to me in third and fourth so I backed out of it. I have a 5spd, the feeling was like a gasser when hitting the rev limiter just cut out and back on. It was more than not the RPM's because it takes some time to spool up but when the twins start spoolin they come on quick, I am just curious thats all,

 

[Devan Manis]

Double J, yours is probably defueling while it shifts and you probably can't build over14-15psi while you are "Staging" right? your fix is probably a BD racer's anti defueler

 

[Double J]

I don't know about building more than 14-15psi at the line, I try to hold it at 10psi for launching... . lacking the billet output. I'll give the "drag" a try next week and see how it acts but I'm afraid I'll still be a candidate for the BD RAD.

 

[Double J]

Double J, yours is probably defueling while it shifts and you probably can't build over14-15psi while you are "Staging" right? your fix is probably a BD racer's anti defueler

Well BManis, you hit the nail on the head. I tried to launch a little harder today but building around 14 psi and stabing the throttle at the light caused a really bad hesitation (defuel) so I had to keep my launches around 10psi.



On a another note, the "drag version" shaved 3 tenths off my 1/4 mile time and I could have probably done a little better with a few more passes. I'd say seeing the pyro buried at 1600 limited the number of passes I was willing to make. :-laf

 

[Devan Manis]

Yeah the drag keeps fueling on the top end to keep the horsepower about the same as peak. Sounds like the BD RAD could do you quite abit of good. hope your trans can handle it.