8 replies to this topic

[leebrine]

HI 

I am rebuiling a 98 mpi all totally original one owner on refitting the throttle body i noticed on the max throttle position there is a L shaped bracket on the bottom of the throttle body that serves as max throttle stop.  However when you manually open the throttle by hand to this max stop teh butterfly valve is not fully vertical i would say it is around 80% open.

Was this done for a reason

would reducing the size of this l bracket to let butterfly valve fully open improve airflow and thus performance

or would teh engine management system not cope with it?

Just seems a very odd design but as i say it is all original never touched so it is definately as teh factory intended

regards

Attached Files

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[Midas Mk1]

I took the bracket off when I ran standard mpi setup. 

[leebrine]

Thank you midas MK1.  So you removed teh bracket entirely and it ran ok, correct? di you feel it improved performance at at beacuse teh angle teh butterfly opens to with the bracket on is very restrictive on airflow.

thanks

[Steve220]

It's not about whether it opens fully, its done to aid throat velocity. It's why i roll my eyes when people fit a 52mm throttlebody to an MPi.

[FlyingScot]

If your are thinking this will give more power or better pickup - sorry not going to happen. It’s set for a reason remember Rover were cheap skates.

 

FS

[leebrine]

HI thanks for the response the comment to assist velocity in the induction makes a lot of sense i will try it both way abut #i am leaning to leaving it on.  I agree why to people fit larger throttle bodies the inlet manifold is so badly desgned i dont see how that would make any difference

[sonscar]

Fit a vacuum gauge and at full atmospheric pressure see how much throttle travel you have left.This may be a bit simplistic but I found it interesting.In my experience Max power is OK for the track and boozer but mid range driveability is king on the road,intake velocity helps this.Steve..

[bogstandard]

It's not about whether it opens fully, its done to aid throat velocity. It's why i roll my eyes when people fit a 52mm throttlebody to an MPi.

I am not an expert but can only talk owning an MPi for 18 years and my experience of it. Had the usual stage 3 kit fitted with the Burlen 52mm throttle body and a complete waste of time. Yes it sucks in lots of air but does feck all. The biggie is the ECU which needs swapping. I eventually went with the SC MPi Throttle Body kit and mappable ECU and wow wow wow. If you want to buy my old Burlen Throttle Body let me know.

[Steve220]

It's not about whether it opens fully, its done to aid throat velocity. It's why i roll my eyes when people fit a 52mm throttlebody to an MPi.

I am not an expert but can only talk owning an MPi for 18 years and my experience of it. Had the usual stage 3 kit fitted with the Burlen 52mm throttle body and a complete waste of time. Yes it sucks in lots of air but does feck all. The biggie is the ECU which needs swapping. I eventually went with the SC MPi Throttle Body kit and mappable ECU and wow wow wow. If you want to buy my old Burlen Throttle Body let me know.

Good real world review 👍🏽
An engine will have a governed VE depending on the mods, you could have the biggest throttle in the world, but the engine will only take in so much air per cylinder stroke. The job of the tuner is to find the best ratio of stack velocity Vs restriction...



Or just shove a turbo on it.