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Discussion Starter · #1 · (Edited)
After hearing so many good vibes about the 160TB I had to try it myself. Managed to get one from SHARKYMGF on the 'for sale' board for 70 quid second hand, bargain!

Took about 20 mins to fit, an easy mod with an 8mm ring spanner! Done the old reset trick with the accelerator pedal and ignition at position II, seemed to do the trick, started first time and idled a bit high to start but calmed down to the right speed very quickly once it had been ticking over for a while.

The difference was instantly noticeable, nicer looking in the bay, no more sticking throttle, a different firmer feel to the accelerator, more responsive, smoother acceleration and overall worth every penny. In conjunction with the K&N and zorst it is worth every pound note!!!:cloud9:

Soon to be r'roaded (taken with a pinch of salt of course!)

Cheers:beer2:
 

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Mike400 said:
contemplating it myself, however as i only have a 1400 k series im wondering if it would be worth the cash?
Don't bother mate fitted one to my ZR 105, wast of time if you ask me made the tick over crap & no diffrence to the performance.
One plus for it tho,sold it for 15 pounds more than i paid for it.
:cool:
 

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mgf
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Have you had it set up on Testbook?

There is an adjustment screw on the throttle body which controls the amount of air in the bypass circuit to the IACV (stepper motor). Without running the car up to temperature on Testbook, you can't see how much air the IACV is getting, if it is out of spec then this can cause idling problems and also rob you of some bhp gains, the MEMS gets confusing signals from the IACV and the Throttle Position Sensor.

I have a Trophy TB on my F and was 'underwhelmed' by it when it was fitted, i only recently found out about the bypass screw and after having it adjusted the difference was quite noticable.
 

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Just fitted one to my R25 1.6
Fitted a viper last week and that improved high-end power and a bit of low-end torque, but the throttle body has made a huge difference to the car. I wouldn't say it's improved power at all- but a few extra horses at 6500rpm aint that important for everyday use, but it has changed the whole feel of the car. The throttle's a lot more responsive- it's hard to explain how that improves anything until you've tried it. It also sets off better and smoother- more like what i would have expected the 1.6 to do in the first place. So with the viper for peak power and the TB for improved normal use the car's feeling great now.
 
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I know it's old hat, but I read some time back about using the throttle body off the 220/420/820 engines - anyone have experience of this?

One of those for £20 from a scrappy may be worth a try.
 

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I've been told that the reason that it makes so much of a diferance is that the vacuum inside the inlet manifold causes the plastic butterfly to deform meaning the accelerator has to be pushed further to increase the revs. When changing to the metal one less pressure is appled to accelerate the same ammount which is why people think the car is more powerful.
 

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Scarlet Fever said:
Have you had it set up on Testbook?

There is an adjustment screw on the throttle body which controls the amount of air in the bypass circuit to the IACV (stepper motor). Without running the car up to temperature on Testbook, you can't see how much air the IACV is getting, if it is out of spec then this can cause idling problems and also rob you of some bhp gains, the MEMS gets confusing signals from the IACV and the Throttle Position Sensor.

I have a Trophy TB on my F and was 'underwhelmed' by it when it was fitted, i only recently found out about the bypass screw and after having it adjusted the difference was quite noticable.
Where did you get it set up?
 

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mgf
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I had mine adjusted by Brown and Gammons, but any MGR dealer can do it, they just need Testbook is all.

The reason the 52mm TB feels better are 2 fold:

a) The standard TB has a 48mm diameter choke point, and the Trophy TB has a 52mm diameter one. Because the butterflys are circular, to find the cross sectional area you need to go back to your school days and apply pi.

48mm diameter = 24mm radius - Pi x r2
Pi x (24 x 24) = 1809 mm2

52mm diameter = 26mm radius - Pi x r2
Pi x (26 x 26) = 2124mm2

This is a 17% increase in cross sectional area, therefore for a given throttle position you are getting up to 17% more air into the engine, making the car more responsive.

b) The other reason is less scientific. It has been my experience on MGF/TFs that very few of them have the tension in the throttle cable set correctly. There is ususally too much slack in the cable, meaning that there is an increased pedal travel before the throttle butterfly starts to open.

When you fit an alternative TB, you have to disconnect the throttle cable and then refit it to the new throttle cam. Doing this means you have to re-adjust the cable tensioner and thus your new TB has a correctly adjusted throttle cable.
 

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mgf
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chris_dpg said:
Is it true that it has to be set up on some sort of dyno though?
No.

Technically you don't have to calibrate them at all, but a poorly calibrated TB can lead to idling problems (the example i was given was that after a fast run on a motorway, when you come off on the slip road and stop (say for traffic lights) a poorly calibrated TB can cause the car to stall rather than idle. Note this has nothing to do with the speed the car idles at).

Here's how the TB works.

It is basically a tube, with a circular flap in the middle (butterfly) on a spindle. Outside the tube, attached to one end of the spindle is a semi-circular 'wheel' with a groove around the outside. The throttle cable attaches at the end of the groove and then sits within it around the wheel. When you depress the accelerator, the cable pulls the wheel round, rotating it thus opening the flap.

Now, when your foot is off the accelerator the butterfly is fully closed. However to maintain an idle, the engine needs some air, so there is a bypass pipe the takes air from one side of the butterfly to the other. The amount of air in this pipe (and thus the idle speed) is controlled by a valve in the bypass pipe called the Idle Air Control Valve (IACV or Stepper Motor) and this is controlled by the engine management system.

Still with me?

Basically the engine management system expects the flow capacity of the bypass pipe to be at a certain level so that it can calculate how much to open the IACV to maintain a steady idle and there is an adjustment screw on the throttle body to set this max flow rate.

However, because the adjustment screw doesn't directly affect the idle speed of the engine (the IACV / MEMS does this) as far as i am aware there is no way you can tell if the screw is set correctly without seeing the flow rate in the pipe and this requires the car to be plugged into Testbook at a dealership.

The proceedure is very straightforward, the car is plugged in and run up to temperature. Then the appropriate screen is selected on Testbook:


Sketch of the Testbook display for calibrating a throttle body

The shaded are represents the target air flow through the bypass pipe, the needle shows the actual flow rate. You then simply wind the adjustment screw in or out until the needle sits within the zone. All in it takes about 10 minutes to do and most of this is waiting for the car to come up to temperature, so it shouldn't cost a lot of money.
 

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3 for 2 fuel pipes

:eek: I'm think of doing an MPI conversion on my 1992 J 214si (currently an SPI)
so i can fit the 160TB but i see the MPI engine has 3 fuel pipes coming up against the firewall but mine has only 2 does it matter.:spanner:

WHYS THAT. PLZ
 

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Personally, I wouldn't bother with such a conversion - it's a fair bit of hassle for little gain (IMO)


There are only two fuel pipes to the engine, be it SPI or MPI - a feed and a return.

Unless I'm missing something?
 

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On the subject of the Trophy throttle body. Recieved mine Friday, fitted it in quickfire time on saturday and am much much happier with her now.

Pickups faster, much smoother, I really feel I'm getting the most out of the other bits and bobs i've fitted.

For the VVC it's a must have IMHO
 
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