Throttle Set Up

Hello all,

I'm new to EFi tuning, in fact I'm a complete novice. I have recently converted my Triumph TR6 from mechanical fuel injection to EFi and I'm now at the tuning stage, where I've found myself completely out my depth. Please be patient with my inexperience and questions. First question as follows.

I have fitted an aftermarket intake manifold & throttle body. When the throttle cable is connected "pedal-linkage-throttle body" I can only get around 85% full throttle. To achieve 100% I would have to carry out some modifications to to the pedal assembly, eg; cutting, bending and perhaps welding, I really don't want to do this.

The car is intended only for street/road use, so my question is should I tell the ECU (MAXX Mini) that the 85% is WoT (100%) or leave as is? I'm usure what effect this would have on fueling.

Thanks in advance,

Richard.

What, exactly, is the throttle body you're using? It should be possible to either find one with a slightly smaller arm, or radius, that will fit or fabricate one.

In the meantime, you can either leave it at 85% to simplify it when you do get 100% opening, or reset the values so 85% open is considered to be 100% by the ECU, which will give the option of slightly tigheter mapping for the throttle.

Personally, I'd go with the former, and sort out the linkage(s).

Thanks Gord for your advice,

I'll take that onboard and leave it at 85%. My thinking is that for my intended use, street, long distance cruising etc, will I ever actually use WoT?

Richard.

You just need a slightly smaller diameter cam or if the installation allows you might get away with a straight arm pivot, although that would generally lose you a touch of control resolution off idle.

If it's a large throttle body you probably aren't losing much anyway.

Thanks Slides,

I don't have access to the car right now (working away from home), but from memory I think the throttle plate diameter is 70mm(?). The part# for the throttle body is "XH206682". I've searched the web for this item and can't seem to find any information on it, manufacturer etc.

Richard.

You most likely will have no gain from opening a 70mm throttle on a naturally aspirated 2.5l engine more than what it already is, you most likely will gain driveability from the engine with a smaller opening and you will get to a point where the throttle opening is providing all of the airflow that the engine can consume, and going further makes no difference. Case in point, I had drivers going quicker, and being happy with the driveability of a car that I changed the throttle mapping to not fully open the throttle on.