924Board.org

[Rob the plumber]

I read in Shaggys intercooler post about "switches" on the throttle body, and how they may need to be cleaned. What do these switches do? My car seems to make the best power at part throttle. At wide open throttle it kinda lays down a little bit.

My car is an '81 with an oxygen sensor. Is this something worth looking into, or am I just getting carried away?
_________________
1981 931

[924RACR]

I have the same sense with mine... but no, our cars (S2's) have only one main pseudo-TPS switch, not the many switches that the S1's have. I've checked mine before, though I might check them again for adjustment... or not.

I still wonder if the mix might be a bit off at WOT...
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[morghen]

i had the same feeling with mine....and i investigated a bit. Couldnt find anything clonclusive. As 924RACR said...the S2 has only a two position reader...IDLE and WOT. I opened mine to check it out...there was some oil inside..i cleaned everything up...torgued the copper blades and fitted it back....i didnt realise any difference...i recently replaced the vacum hooses to try and figure out why my exhaust manifold is getting a bit red when WOT-ing it....nothing conclusive yet and the car still "feels" slower when i WOT it.

The "feeling" comes from the fact that the cars are fast when launching in an overtake or doing 120 and accelerating (and you dont WOT them)...and you would expect them to be faster if you press the pedal more...well they are...but not much more faster...with a NA this pedal to power thing is linear...but with the turbo is not.

This is an interesting issue that could be caused eigther by human differential sensing or something related to the turbocharging system...gas speed.
_________________
Supercharger and EFI kits
https://www.the924.com

[Rob the plumber]

Mine feels like it makes a lot of torque if I roll on the throttle. But like you said, it does not feel much faster when all of the throttle is applied. Maybe something like the restrictive cylinder head is limiting air flow?
_________________
1981 931

[Rasta Monsta]

With increased boost, I think the stock WUR is over-enriching the midrange mixture at WOT. Read more HERE and HERE
_________________
Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[Rob the plumber]

An overly rich condition does make sense. I guess one of the first modifications should really be a wideband O2 to see where you are at in the first place.
_________________
1981 931

[Rob the plumber]

What about making an adjustable one yourself?

http://forums.pelicanparts.com/showthread.php?s=&threadid=218814
_________________
1981 931

[Rasta Monsta]

How does it not make sense? The WUR gets a boost signal from the manifold, and decreases control presure to dump more fuel. In order to work, it is "curved" from the factory. Getting more boost, sooner, makes the system respond with a richer mixture at a lower RPM level than when it is actually needed.

As for that other guy's thread, looks very interesting. If you did a little before and after with a dyno/AFM run, you'd be coming up with an important thread.

Oh, and BTW, I realize that Vaughan isn't running higher boost, and I also recall Morghen having a similar complaint about his 931 (feels stronger at less than WOT). Could be a limitation of the WUR, beats me. But, as I said, very worth investigation.
_________________
Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[ideola]

My SI running stock boost feels the same way.
_________________
erstwhile owner of just about every 924 variant ever made

[Rob the plumber]

[Rasta Monsta]

_________________
Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[morghen]

[Rasta Monsta]

Actually making fun of myself for misreading Rob's post.
_________________
Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3