matt_gsxr
|
| posted on 29/4/11 at 11:35 PM |
|
|
Raz,
I can't remember which ECU you are using but....
I had a similar problem to yours, which was (in my case) due to slightly sloppy linkages, and a TPS that didn't see the angles perfectly.
Having recently changed to Speed-Density (for the turbo) it seems that this is way less sensitive to these subtle throttle position things at idle
(not great everywhere, but good at this tip-in range).
So, back to the ECU thing. If you are using megasquirt, then the ITB mode allows you the best of both worlds (Speed density at low power, and TPS at
high power).
Just a thought,
Matt
p.s. I'll try to find you at Stoneleigh as I'd like to see your car in the flesh. I still need to sort the map on mine (new engine,
different cams, turbo etc.), but the new lambda probe arrived yesterday and Stoneleigh isn't from here (only 45miles).
|
|
|
|
|
RazMan
|
| posted on 30/4/11 at 07:44 AM |
|
|
I'm using an MBE 970 which seems to have soooo many whistles and bells it can be a bit daunting to a novice like me. The density that you
mention must be the equivalent to an index map - a monotonic curve that reflects the relationship between throttle angle and airflow but can be
tweaked in so many ways. I would guess that some improvements might be possible in this area but as a complete novice I would not like to play around
too much in case I do something silly - that's a job for the dyno guys.
ps I'll be glad to meet you at Stoneleigh. I think Sunday is my chosen day - just waiting to see if SWMBO can make up her mind 
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
|
|
|
BaileyPerformance
|
| posted on 13/5/11 at 09:02 PM |
|
|
quote:
Originally posted by RazMan
Now that I have my throttle bodies all nicely set up and running beautifully I have just one niggle which spoils an otherwise perfect setup.
When closing the throttles at mid - high revs and slowing down (say for a corner) I find it quite tricky to step on the gas again gently. It feels
like the the throttles are sticking in the closed position and then 'let go' causing a rather jerky pickup. Everything works fine at low
revs so I assume it must be the high vacuum caused at higher revs on the over-run.
I have made a progressive throttle cam to give the pedal more movement in the lower part of the range but it has only made a partial improvement.
Is there any way of getting this jerkiness out of the throttle? Any suggestions would be appreciated.
Hi, are these bike bodies you are using? if so i have seen this problem before, normally on bike throttle bodies the link is done via a pair of
springs either side of the linkage metalwork, one spring has an adjustable screw used to adjust the balance between the throttles, the other has no
adjustment. The problem is on a car engine the vacuum is normally much higher than on the bike engine so one of the pair of springs is compressed
momentary putting the throttles out of balance. The throttle next to the throttle cable linkage will work OK, the next throttle is normally the worst
effected as this throttle operates the remaining throttles.
The way to check is to remove the air filters and with the engine running snap open the throttle watching each throttle plate to make sure they all
open together, then watch the springs between the throttles to see if any are compressing.
The way i have fixed this before is to drill a hole down the center of the spring (without the adjuster) tapp it M4 and install an M4 capscrew. With
adjuster's both sides of the linkage (between each throttle) you are able to balance and effectively lock off in place preventing spring
compression.
|
NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
|
RazMan
|
| posted on 14/5/11 at 09:22 AM |
|
|
My throttle bodies are not really conventional and are contructed from the original secondary butterfly castings - and I suspect that is part of the
reason for the strange behaviour.
Check out this thread for the full story
http://www.locostbuilders.co.uk/viewthread.php?tid=145114
Anyway, I can now happily report that I have got things working nicely now. It took a lot of tweaking, fettling, remapping, swearing etc but overall
I'm really chuffed with the result 
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
|
|
|
