WOT Rpm spikes at high MAP but not part throttle ?

ae1969 · Post by **ae1969** » Mon Jun 12, 2006 7:40 am

Problem: RPM spikes at WOT at high MAP. 200 kpa. 3K rpm + and then flattens .....and then spikes up again.

At 200 kpa. The minute boost jumps up to 200kpa we have the spikes. Very noticeable while driving. Wideband does not pickup any fluctuations. I am still logging wideband even thought the scale is off but I still don't see any fluctuations. It feels like its going lean, rich, lean.....etc.

Set up:

- 2.5L Turbo running MS2 and EDIS
- running conservative AFR's 12-11.5 at bull boost ~3K rpm to redline (ignore any afr readings I have on the charts, the values don't match my visual display)

Partial Solutions:
At PART throttle and if I get it up to full boost very little if any boost spikes at 200kpa.
At part throttle at 170 kpa and if I throttle it up to full boost slowly. NO spikes and perfect flat rpm.......

We did notice some AE that was causing some pulsating. I have now tuned map AE and throttle AE both working well until you hammer on the full boost. I have the threshold set at the maximun for both MAP and TPS. ~200kpa/s and 25.5/s. We tried setting the enrichment to 0 on the cells of AE just to tune of the VE tables at WOT.

I am looking at any and all suggestions of what could be causing these spikes.

Thanks

ae1969 · Post by **ae1969** » Mon Jun 12, 2006 7:41 am

Chart example....[/img]

mops · Post by **mops** » Mon Jun 12, 2006 12:19 pm

ah 944 turbo... i always wanted one... are they really that great in terms of handling as they say ?

anyways, to the point... well... you do get rpm spikes/dropouts...

can you desribe which ms r u running and your crank pickup setup you got there ?

then i'll be able to advice better...

you got pics of your car ? it is 2.5 or 2.7 turbo ? do they all have factory LSD's ?

ae1969 · Post by **ae1969** » Mon Jun 12, 2006 1:23 pm

mops wrote:ah 944 turbo... i always wanted one... are they really that great in terms of handling as they say ?

anyways, to the point... well... you do get rpm spikes/dropouts...

can you desribe which ms r u running and your crank pickup setup you got there ?

then i'll be able to advice better...

you got pics of your car ? it is 2.5 or 2.7 turbo ? do they all have factory LSD's ?

Handles like a dream

Here is the power plant.

some....

I am running a 36-1 EDIS. The car is running great. MS2 V2.67Beta but this problem was present with 2.35. I just wanted to try a few new features on the test mule.

Just having this lingering problem with the RPM spikes at high map.

I have searched a little and found that I should try resistored plugs. I am picking some up on my way home to give it a try.

What is funny if I throttle slowly upto full boost........ little to no spikes.

Thanks for your help.

mops · Post by **mops** » Mon Jun 12, 2006 1:28 pm

seriously, dude... i do not know...

they only think i'm thinking is in megatune settings, in ignition setting - play with predictor algorithm and normal running values there.

aswell if you run ms v3 board then you might play with vr pots and see whether thay helps you at all...

what kind of horsepower this 944 produces ? is it factory LSD ?

ae1969 · Post by **ae1969** » Mon Jun 12, 2006 4:16 pm

mops wrote:seriously, dude... i do not know...

they only think i'm thinking is in megatune settings, in ignition setting - play with predictor algorithm and normal running values there.

aswell if you run ms v3 board then you might play with vr pots and see whether thay helps you at all...

what kind of horsepower this 944 produces ? is it factory LSD ?

WOOOOOOOOO HOOOOOOOOOO it was the plugs.....!!!!

SHE IS pulling like a bat out of hell again!

She will run 300+rwhp and 300+lbft at 15 psi.

WOOO HOOOO

So happy its purrrrring like a kitten........but roars like a lion!

Yup factory lsd with hardened gears. Without it you are spinning one wheel like its going out of style....

WOOO HOO... thanks