Bigger Throttle Body, TPS reference changes!

[VX L67 Getrag]

As was pointed out to me from a very smart human being(yoda69), when changing throttle bodies on any car there will need to be a lot of tps reference tables changed (especially for transmission as it will be very pronounce), I had a look through the xdf & there A HELL OF A LOT of tables to change!

Is there an easier way of just changing a reference point in the cal file to make it 10% less sensitive for the change of all tps references?

What is a stock VT-VY throttle body? I think 65mm & then they get bored out to 69mm is this right? if so everything would need to be changed by 5,8% by my calculations?

[The1]

yeh im having similar issues, i have a 69mm TB im trying to tune for, the tps gives out the same voltage at the same TPS % as the stock one, yet im having issues with shift points being so sloppy it slips sometimes, not the case with the old one back on there!

[yoda69]

The basic issue, is that for a given amount of throttle (TPS%) the vehicle is now getting more air, and hence more power.
Everything needs to be moved down lower in the TPS readings.
It's actually about a 12.7% difference going from 65 to 69mm, as your interested in the throttlebody area.
((69/2)^2-(65/2)^2)/(65/2)^2, have ignored adding pi in as they all cancel out.

Yes there are a lot of tables (Pressures, gear up/down shift points, TCC lock/unlock points, etc.), and no, unfortunately I don't know any easy way to fix it.
The only good thing in this case, is a lot of the tables have 12.5% increments, so maybe be able to copy the data and move down one line, as this close to the calculated 12.7%.
If you do a histogram of airflow Vs TPS% with the old and new throttle body, may be able to better understand what is going on.

yoda69

[VX L67 Getrag]

AS I said smart bugger, or genius I like to refer!

I thought I was o.k. with maths & just did 69 minus what ever % until it hit 65 & thought that was it! but proven wrong yet again!

Yeah I guess it's not too hard to move them all down 1 line & then make up the % less from the given 2nd line(old 1st line).

But there is a hell of a lot of tables to mod & not just in trans either, thats why I was hoping somewhere in the cal section there may have been a tps reference that could be changed by 12.7%

Thanks!

B.T.W. I should have actually had this in the general tuning topic sorry

[Holden202T]

easy fix, put a hydraulic auto in it

[The1]

here's was a screenshot of me playing just after i put it on ages ago, but dont do anything really other than to say yes airflow increased!! lol 18-25% is a problem area with trans stuff for me.

Before


After

[VX L67 Getrag]

I thought you might be interested in this thread the1!

So did you change all of your tps reference tables for both engine & trans?

[The1]

i havn't touched anything yet, have only tuned the fuel and spark, so it's all running right, the tps has the same voltage at the same opening as the stock TB but i guess it's like yoda said the airflow at the same throttle opening is now larger which upsets some tables. So i guess just gotta figure out what ones it's upsetting, for me it was upshifts slipping so the pressures and shift points are different

[delcowizzid]

raise upshift and downshift mph by around 2-4mph at under 50% TPS normally fixes the shifting side of things 50% upwards can stay the same

[The1]

thanks delco ill try that, i noticed the issue was around 25% tps, low throttle or 50% up to wot was fine.