Suggestions

[NP_00'T/A]

Ok I just had a few mods done to my car and I had soemthing interesting happen to me the other day... I was on the open highway and decided to open her up real quick to see how she did at a higher speed. Well at about 120 the rev limited kicked in and shut me down. My question now is a LS1 with 3:73 really only going to do 120 mph or is there something wrong ? My friends mustang GT with 3:73 does 130+ and god knows he only has like 210 hp and stuff so i'm kinda concerned. Its not like I every really go over 80 but if the car is running poorly or something is wrong i'd like to try and head it off before it gets worse.

My mods include:

QTP long tubes
QTP ORY
SLP LM catback
SLP lid/filter
3:73 gears
Dyno Tune


Now at the track I ran a 13.5 @ 103mph on street tires with only the lid and catback. At this time the car Dynoed in at 310hp and 333 TQ. With the full exhaust , gears, and tune on MT drag radials i ran a 13.29 @ 106mph. With the new mods I dynoed in at 322HP and 333 TQ. I don't really know whats wrong but I would like some suggestions on what it could be cause i'm pretty lost atm. Thanks

[ar0ck]

Who tuned it?

[foff667]

speed limiter...if the car wasnt optioned for the better rated tires you'd hit the speed limiter at 118mph...thats how my Z28 was setup before tuning. Sounds like your tuner just didnt know what he was doing :shrug:

[Tru2Chevy]

:stupid:

- Justin

[enRo]

LS6 intake and call it a day

[qwikz28]

with 3.73s and granted a redline of ~6000rpms your theoretical top speed should be 175. i would assume TTP didnt take out the limiter if your car wont pull past 120.

[NP_00'T/A]

the car did alot faster then 120 before the new mods :) Oh well

[foff667]

odd either way...many of the origonal 2.73 geared cars had the 118 speed limiter...wonder if yours was one of these or what now that your saying you could go over 120 before mods :shrug: I'd really need to view the tune to see whats going on inside its little brain hehe

[Tru2Chevy]

If it hits 120 and stops pulling like you hit a wall, then it's got to be the speed limiter. Maybe something got changed by mistake when they tuned for your gears?

- Justin

[NP_00'T/A]

Well it was kinda like the rev limited went off like when its being dynoed. It felt like it was up towards 6k and the whole car just back off like it shut down from a real high RPM. The car was cruising around 3-3.5k rpm at 80mph ( used to be 1.8-2k rpm with the 2.73 gears) so i'm assuming it was up towards 6k to get to 120 mph.... wasn't really looking at the tach since i wasn't expecting to get shut down but I could also hit up Rt. 78 and check it hehe

[foff667]

yeah it would probably be at the top of 3rd gear with 3.73's

[NP_00'T/A]

I had it in (d) so it was able to shift into overdrive but we shall see :)

[foff667]

yeah but generally dynotunes are done in 3rd gear since its a 1:1 in autos...4th gear 1:1 on m6's

[V]

this may not apply... but maybe your trans wasn't going into overdrive? You mentioned a while back you thought you may have been having trans troubles, pehaps its getting worse? :shrug:

[qwikz28]

my saturn has a limiter at 99. it hits the limiter in 4th gear and refuses to go into 5th while at the limiter. thats probably what you were experiencing. your car had a whole other gear left, its just the limiter said no thanks i'll stay where i am

[NP_00'T/A]

Ah ok makes sense... oh and the trans thing was fixed it seems the guy who did the tranny service knocked off a electric selenoid when he was putting the pan back on and it was shifting really sloppy which gave it the feel of gears slipping in and out. Once they reconected the selenoid it was perfect so you probably right about the whole dyno tune thing and third gear...

[WildBillyT]

speed limiter...if the car wasnt optioned for the better rated tires you'd hit the speed limiter at 118mph...thats how my Z28 was setup before tuning. Sounds like your tuner just didnt know what he was doing :shrug:

Yep, this could be it. :shock: What tires were originally on the car?

[foff667]

Followup:

its not the tune why he's limited to 120mph...Im not sure what it is exactly but its not in the tune.

[r0nin89]

To my knowledge a speed limiter will cut your fuel drop your rpms then kick it back repeat until you either shift or let off. A speed limiter feels like you just slammed the breaks. its you car saying wtf do you need to drive so fast for. Which one did it feel like?

[foff667]

thats it!!! he's hitting his rev limiter in 3rd gear!!!...the 3-4 will not shift at WOT as commanded by the computer, THANKS! See in stock form with 3.23's or 2.73's in an auto this wouldnt necessarily be an issue cuz 3rd gear would pull clean to 140, but with 3.73's he'll top out at ~120mph in 3rd gear & it would need to shift to 4th...easy fix, but I probably wouldnt have thought twice about it even if I were tuning it, seeing as how I generally dont go nearly that fast hehe.