3rd gear pull, rpm hump

[isnms]

blue line is rpm: 10psi boost, 3rd gear, 3500rpm
i don't notice it in 2nd gear. don't have anything for 4th yet.

the start of the hump, where it starts to shoot up, is about when it first hits 3500rpm. that is the first point of correction on my safr. could that be it? should i move it up further in the rpm?

i'll try to get a log with the safr out of the loop.

i've attached two zt-2 logs in the zip file.

edit:it doesn't seem to be when i lay on the throttle. the one at the bottom, i'm already into the throttle for a while before the hump

 

[rakkasan]

blue line is rpm: 10psi boost, 3rd gear, 3500rpm
i don't notice it in 2nd gear. don't have anything for 4th yet.

the start of the hump, where it starts to shoot up, is about when it first hits 3500rpm. that is the first point of correction on my safr. could that be it? should i move it up further in the rpm?

i'll try to get a log with the safr out of the loop.

i've attached two zt-2 logs in the zip file.

edit:it doesn't seem to be when i lay on the throttle. the one at the bottom, i'm already into the throttle for a while before the hump

Two thoughts: How is your clutch? It could be slipping a little, but you would see it in 4th gear too. Is there a chance that you're losing traction??? I'm by no means offering reasons, just bits of info to jog you thought process....

 

[isnms]

clutch was one if my first thoughts too. wouldn't i see it in 1st and 2nd too?
would it be more prominent in 4th?
i'll have to take some 4th gear data to see.

it's a new clutch, but that doesn't mean much. the last clutch started to separate on me and gave me a terrible vibration in my pedal, and it was new too.

 

[jbsupra89t]

I was just gonna say clutch... someone beat me to it though. Look into it in more gears as well, low RPM pulls.

-J

 

[isnms]

here's a 4th gear merge onto the highway this morning. i had to lighten up on the throttle @~3000, the dip in the pink line.
i don't see the rpm hump though. (this log is from my pocketLogger)

 

[rakkasan]

here's a 4th gear merge onto the highway this morning. i had to lighten up on the throttle @~3000, the dip in the pink line.
i don't see the rpm hump though. (this log is from my pocketLogger)

You didn't notice a loss of traction did you? The only thing I can think of that would cause your RPM to spike & then drop like it does in the first graph is a momentary loss of friction at either the wheels or the pressure plate.

 

[isnms]

i didn't notice that. i did hear/feel the engine race and settle back down, but no traction loss, that i noticed.
it would be nice if that's what it is. replacing tires is better than another clutch.

 

[shaeff]

you most likely wouldnt feel the clutch slipping in first and second, as you're more likely to break the tires loose in those gears. when you hit third, it's a crapshoot, fourth, you'd feel the clutch slipping. that's how many people find out if they have a slipping clutch, is a hard fourth gear pull, because you're putting a LOT of stress on the drivetrain, but it's too tall of a gear to break the tires. (in most cases)

-shaeff

 

[moorman]

I'll have to echo the clutch/traction response. One note though, is that unless you have an open diff, you should be able to feel wheelspin w/ the butt-meter. It could be either, but unless you have poor tires or were on a slick surface, I wouldn't expect 10psi to break traction in 3rd.....especially if it isn't doing it in 2nd.

I have traction issues in 1st & 2nd, but by 3rd I rarely see it.

Here's a small zto clip from some 2nd gear wheelspin, but I get off the throttle because it's very apparent by feel.
http://members.provalue.net/moon/2nd_gear_wheelspin.zto

 

[MK3Brent]

Now that I see that was the RPM line, there's no doubt in my mind that's a little slippage.

 

[isnms]

could it be that i reached the limit of the stock clutch?
it downshifts fine. i didn't experience any of this before this weekend when i finally configured my s-afr.

shaeff - are you still using the clutchmasters stage III ? how's it holding up?

thanks for all the info guys

 

[cjsupra90]

most likely clutch issue. as stated before, tire slipage in lower gears and clutch slipage in higher gears.

On a side note, if you look real close to the 2nd gear run, you can see that it is ever so slightly starting to happen and the 2nd 3rd gear pull seams worse.

In a later post you did the 4th gear pull and you didn't notice it, but you also said that you had to lift off the throttle at around 3000 and the problem seems to be at around 3500 according to your 1st post. Try another 4 gear pull that you dont have to lift on. If it is the clutch, if should get worse in 4th and or in 5th.

Another option is to try it is 5th, you dont need to do a full pull, just cruise up to around 3000rpm and the lay in to it and shoot up past the 3500rpm range. if its the clutch, it should be worse then in any other gear. Just remember, you will be most likely going above the posted speed limit, so I am not responcable for and tickets that you my receive if you so choose this test.

 

[shaeff]

could it be that i reached the limit of the stock clutch?
it downshifts fine. i didn't experience any of this before this weekend when i finally configured my s-afr.

shaeff - are you still using the clutchmasters stage III ? how's it holding up?

thanks for all the info guys

the CM stage III is still holding fine. i wasnt sure if it would hold over 300rwhp, but it's doing so like a champ! (i'm assuming i'm a bit over 300rwhp, i havent actually dyno'd yet, but i've got more mods, than many others on my healthy motor, pushing 15psi, so i figure i'm thereabout)

also, something to remember, i'm still on the w58 tranny. the r154 CM stage III might hold more torque than the one for the w58. but anyway, i love it. the pedal feel is identical to stock, super smooth engagement, and no issues with my fidanza FW either.

-shaeff

 

[isnms]

today's logs
i only noticed it once today. it's in the last 5th gear run.
it's like you described cjsupra90, but it's not in the other 5th gear run.

I'm attaching the logs. they are pocketLogger files and can be viewed with the PLViewer. Make sure to save it as a .jar file. Windows will want to change it to a .zip.
edit: oh, it has to be the PLViewer for PocketLOGGER ZT files.
http://www.pocketlogger.com/viewer/zt/PlViewer.jar
website:
http://www.pocketlogger.com/index.php?pid=utilities

 

[bigal0043]

what does that pocket logger hook up to? your wb?

 

[isnms]

^yes. It's for using a pda, to log the zeitronix zt-2 wideband, instead of having to haul out the notebook every time i want to take logs

 

[bigal0043]

thats really cool.. i wish i could get something like that for the aem unit...

 

[hottscennessey]

sorry.. i know i'm no help to this subject.. but isnms, is the pocket logger the program that zeitronix shows on their main page? If not.. details? And how do you like it?