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jay71 jay71 is offline
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Join Date: Nov 2005
Location: Evergreen, CO
Posts: 170
Throttle response issue

Hey folks. Bought a 930 last fall and basically tore into it without doing much driving because it was leaking oil and had a tired turbo. Now I've got a nice running car that seems pretty fast to me with the following engine ancillary mods:

GHL Headers
RarlyL8/M&K center outlet muffler
934 center outlet WG pipe
Tial 46mm (0.8 bar spring- gauge holds at about 0.9bar @ max boost)
K27 7200 from IA
Kokeln long neck IC
Cheap plastic BOV provided by Kokeln
Leask adjustable WUR w/RPM solenoid

Because I haven't driven a rear-engined car and I plan on attending some DE events when I can fit them into my schedule but until then I'm just learning as I go. I've had some sphincter clenching moments here and there as I figure out things like, "...jeezus...that guard rail sure looks close...guess I shouldn't brake in the corner...stay on the gas.." etc. I imagine I'm a bit touchy with the throttle and tentative- which might be my worst enemy at this point.

One thing that I've noticed which doesn't seem right is when I'm on boost in the 0.6-0.8 bar/5-6000k rpm range and I come off the throttle it cuts out dramatically and feels like I'm running into a brick wall. I've tried to modulate the throttle with slight movements and am having a tough time working with this characteristic. It's a bit worrisome as it abruptly unweights the rear of the car and it feels like I'm not in control...this makes me very hesitant in the corners, around other cars in high speed sweepers, etc. I've already had a few involuntary lane changes due to this issue. Not sure if this is the nature of the car- perhaps newby driver error...or perhaps there's something not quite right in the engine bay. I've noticed a considerable improvement in throttle response since I've eliminated the factory BOV assembly- things happen when I want them to acceleration-wise...but deceleration-wise the cutoff is amazingly abrupt with the slightest of pedal movement. I'd appreciate your thoughts on this one (normal behavior/driver error vs. mechanical issue) as it seems to me that it's only a matter of time before I spin out at an inopportune moment. It's unfortunate as I seem to be "white knuckling" as opposed to attacking the road and having fun. I have an LM1 and am beginning to fine-tune afr's...but I don't think this is an afr issue; seems more related to fuel supply/boost....or sucky driver!
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Jay
'86 930
'60 Land Rover Series II SWB

Last edited by jay71; 06-26-2008 at 05:21 PM..
Old 06-26-2008, 06:57 AM
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