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Aug 1, 2010, 9:49am

The MGF/TF Register :: General :: Technical :: Throttle Body - Not 48 or 52mm

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Topic: Throttle Body - Not 48 or 52mm (Read 1,132 times)

Tony Williams
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Throttle Body - Not 48 or 52mm
« Thread Started on Jul 31, 2006, 11:38pm »

Hi I found these while looking on eBay, they are for a K-series for the Lotus. I assume these can be fitted to any K-series, what effect would they have on the car?

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?V....AMEWA%3AIT&rd=1

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Steve White
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Re: Throttle Body - Not 48 or 52mm
« Reply #1 on Aug 1, 2006, 6:49am »

They can be fitted to a K-series but they are designed to be used in conjunction with a modified engine (i.e. a ported head and hotter cams) and a remappable ECU. Bolting them onto an otherwise standard K would almost certainly result in more problems than benefits.

There are some RR stats around that show on a standard engine 52mm is about the optimum. The 56mm TBs that are sold on ebay have been shown to reduce power over the 52mm, which shows bigger isn't always better. I suspect slapping these MTBs onto a standard engine could have even worse results as the ECU simply wouldn’t be able to adjust the fuelling enough to match the increase in airflow.

You also need to be careful when buying MTBs that youi buy short ones, as some require the front boot wall to be cut out to gain the room needed to fit them (take a look at a Cup Car for example). In addition to the MTBs you will also need suitable new filter, backplate and airbox, which will set you back the best part of £300-400.
The ones in the ad also dont seem to be complete, they dont have any linkages or fuel rail, so you can add another couple of £100 to buy those

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Yigit
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Re: Throttle Body - Not 48 or 52mm
« Reply #2 on Aug 1, 2006, 8:13am »

It is really expensive to get performance in the F/TF after a point. Damn

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andrew
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Re: Throttle Body - Not 48 or 52mm
« Reply #3 on Aug 1, 2006, 8:22am »

I have to agree the best bang for bucks seems to be the air filter, 52mmT/b and an free flowing exhaust, all this was worth 118.5bhp at the wheels. Now to go the next bit, remaping, reworked head new fuel injection system, better exhaust manifold plus,plus, plus

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Re: Throttle Body - Not 48 or 52mm
« Reply #4 on Aug 1, 2006, 4:17pm »

Direct To Head Multiple Throttle Bodies - DTH MTBs are a proven way to increase performance, at a cost in terms of fuel. The standard set up uses a single throttle body mounted in line between the air intake and air filter and the inlet plenum and manifold. DTH MTBs replace all of these items and consist of 4 individual throttle bodies, mounted as the name suggests, directly to the cylinder head.

They work firstly because the intake route is simplified to the max, being a set of 4 individual trumpets mounted directly on the head and also because they replace the precise fuel dosages provided by the fuel injection systsm with a cruder, larger dose of fuel meted out individially to each cylinder - that's right you loose your fuel injection.

The upshot of this is that they can give up to +15bhp, but at a cost that is felt at the petrol pump in so far as they result in reduced fuel efficiency.

Steve has rightly pointed out that they work best in conjunction with other mods, particularly with cylinder head porting. He has also stated that you will need to replace the MEMS to get them to work. The MEMS is programmed to deal with a fuel injection system and as such cannot run DTH MTBs - but there are aftermarket engine management systems that can - Emerald is probably your best best in this regard. To get them to work to thier best then you also need to factor in a little rolling road time - just to get the map in the aftermarket ECU spot on for your car. Lastly, due to the confined engine bay in the F, shorter trumpets are needed to get them to fit (without boot bulkhead modifications). Short trumpets result in less power from the MTBs (this is why the Cup Cars have the bulkhead cut away - longer trumpets). You also need an air filter to cover the trumpets - this can be expensive and normally results in a box to cover them all that acts like a plenum and an air intake pipe routed to an external source.

Despite all this, personally i think they are a good way to go and know of a couple of Fs where they have been used to good effect, but it is not a simple bolt on and go solution - as with just about all reasonable power increases on the 1.8 K4 there is more than meets the eye to resolve when fitting them.

« Last Edit: Aug 1, 2006, 4:33pm by Scarlet Fever »

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Tony Williams
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Re: Throttle Body - Not 48 or 52mm
« Reply #5 on Aug 1, 2006, 6:45pm »

Thanks guys.

I wasn't looking at buying it for my F, I've seen these around and really wondered if they make much difference and would it be worth considering as a future mod. Seeing that one on eBay reminded me to post asking about them.

I think I'll give it a miss for a future mod to put on my list.

Thanks

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Bruno
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Re: Throttle Body - Not 48 or 52mm
« Reply #6 on Aug 2, 2006, 11:38pm »

Nice TTB's , but as Andy say, they wouldn't fit on our K-engine, they are designed for VHPD-engines, fitted in the Exige.
There is not enough room to fit these. :'(

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Re: Throttle Body - Not 48 or 52mm
« Reply #7 on Aug 15, 2006, 12:45pm »

hi the next thing you need to do is replace back box. I did this and was v/happy with result
also chiping AFTER you have done box helps

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