So a few words on the subject of bored throttle bodies....

[Wabbitkilla]

Some of you know i've got one that was done by Maxbore.
The interesting thing you might not realise is that in the process of boring out the throttle body, a few protuberances are removed effectively smoothing airflow  thus cutting down disturbance.


Standard;


Bored & flowed;


Now there's been plenty of discussion and argument over on Spyderchat about the effectiveness of this modification, and obviously opinions vary. So I'll go from personal experience when describing the effects mine has had.

Throttle response is snappier, obviously you're opening a bigger hole up letting more air through. Initially this appears to the ecu as simply the throttle opening quicker than normal, but when fully open at full chat you're getting the full benefit of a larger bore.

Ste followed me up Cat&Fiddle after we fitted it and the car gave a more noticeable more purposeful noise - with standard intake plus Markiii pipe. I could also sense a tad more eagerness in the engine, but you never know if it's yourhead telling you for real, or just the added noise making you feel it's more eager. Either way i was pleased with the effect.

Armed with the lightened flywheel later on this improved throttle response further, making for a more "racing car rev happy time".

The next mod going in is an Apexi power intake, which i think is a sensible move. You've increased the ability for the engine to swallow more oxygen, but remember the standard air intake piping is a restriction too. I will be fitting a PFC at the same time.

Rob - I think the PFC will cope with the change ok, but obviously airflow -vs- TPS will be different, but the MAF should pick that up. So you can probably get away without a remap, but as with all performance modifications to make best use of it would be to have the map adjusted. May not need much though eh?

This is a great deal for everyone, and although i lose my originality i'd recommend it to anyone. I went out and bought one from a breaker to get mine done, they're not excessively expensive to obtain and you can always sell yours on afterwards to the next group of people getting the mod

[spit]

I have nothing technical to add, other than to say that Nic's TB job is a beautiful piece of work and - combined with his lightened flywheel and freer-flowing Janspeed - makes for a very purposeful and responsive engine.

Good to see that Rob's plans are to maintain the slight offset of the stock butterfly angle. this will make the mod accessible to those without additional engine management.

[Anonymous]

I must admit I'm tempted by the mod, but not convinced it's going to improve on what I've already got, when you compare the difference between Danny's car and mine, they are almost identical with exception to the induction system, I'm using the Markiii pipe and K&N and Danny's using AEM system so in theory Danny is pulling more air but producng less BHP - not much difference I know but it's still a difference.

When I spoke with Chris (Hypersport) about this he did seem to think that the standard design (well markiii + filter) was more than capable of giving good results.

Sound is not that important to me as the exhaust more than makes up for it, as well as those lovely cams  s:D s:D  

Just to remember I'm talking N/A and not turbo.

[spit]

The difference in profile of the intake is very much smoother on the bored TB though Rob (ie the other Rob   s:wink: :wink: s:wink:  ). Surely that will pay dividends?

[Anonymous]

The difference in profile of the intake is very much smoother on the bored TB though Rob (ie the other Rob   s:wink: :wink: s:wink:  ). Surely that will pay dividends?

I'm not sure Ste, maybe someone out there could comment on this - Tem what's your take on this?

[Wabbitkilla]

See what i mean about lots of discussion and varying opinion.

At the end of the day, you pays your money and you takes your chance.
For me with the standard intake plus Blitz lm panel and Markiii pipe it made a difference, subtle admittedly but i like it.

[custardavenger]

See what i mean about lots of discussion and varying opinion.

At the end of the day, you pays your money and you takes your chance.
For me with the standard intake plus Blitz lm panel and Markiii pipe it made a difference, subtle admittedly but i like it.

Like Nic said. Thats why I'm doing it. A mod for one person may transform the car, another may notice no difference. There are plenty of mods out there that add no horses at all but are still popular.

[davidhowson]

Some very interesting comments and with the likely(?) GB on the Apexi could work well.

However, does anyone know of a downside of this mod when used on the SMT set up?

[custardavenger]

Can't see there will be any difference for the SMT unless it uses a different body.

Another thing to note. If anyone is mot sure about it as a power increase then think of at as weight saving. And as its high up it will lower the CofG which is a handling mod. lol

[aaronjb]

The SMT TB assembly is different - it has all the drive by wire gubbins for the SMT.

Having said that, I don't know if the actual ally casting is the same - making the boring process identical.

[Anonymous]

Another thing to note. If anyone is mot sure about it as a power increase then think of at as weight saving. And as its high up it will lower the CofG which is a handling mod. lol

I'm sold   s:lol: :lol: s:lol:    s:lol: :lol: s:lol:    s:lol: :lol: s:lol:    s:lol: :lol: s:lol:

[ChrisH1978]

The difference in profile of the intake is very much smoother on the bored TB though Rob (ie the other Rob   s:wink: :wink: s:wink:  ). Surely that will pay dividends?

I'm not sure Ste, maybe someone out there could comment on this - Tem what's your take on this?

My recolection of GCSE physics lessons tells me that the smoother it is the sooner boundery layer seperation occurs, potentially increasing turbulence/drag - if that's an issue!? If I dig deep enough into my secondary education though, and thinking it through a bit... wouldn't increasing the diameter, increase the volume (as the velocity should stay the same - thinking N/A engines), reducing the pressure, reducing the temperature - which I think is a good thing!?

[Anonymous]

so what you are saying is that the section should be concave / convex (I can't work out which!!) to eliminate any turbulence?? I think this was the basis on which traditional carbs worked in order to create a pressure drop to draw in the fuel. I maybe wrong, and obviously thats not the requirement here but it's interesting in relation to turbulence..

[Chris]

i've found some pics of the smt tb over on SC..

http://spyderchat.com/forums/index.php?showtopic=38563

i'm thinking of maybe combining the sc mod with this one and possible a lighter flywheel..

[custardavenger]

i've found some pics of the smt tb over on SC..

http://spyderchat.com/forums/index.php?showtopic=38563

i'm thinking of maybe combining the sc mod with this one and possible a lighter flywheel..

Ooh good find Chris. I must admit I didn't realise the SMT uses a different throttle body. Erm, that may be an issue. I could really do with comparing both types to check that the tooling i'm making will be suitable for both.

Any offers to meet up and pull one off? Or does anyone have measurements or potos of the two together?

[Chris]

Any offers to meet up and pull one off? Or does anyone have measurements or potos of the two together?

Steady on now, i'm not that kind of chap!!   s:lol: :lol: s:lol:  
I don't know how long or how hard it would be to remove, but i'd be up for an experimental inspection/measuring session at some point..

It would have to be after I get back from Le Mans though, and I see you're in nottingham so not exactly close to me - maybe at a meet somewhere that we are both going to?  Jae or Anglesey perhaps?

[custardavenger]

Chris I Can't remember exactly where your based but i Drive down past Oxford all the time so if your near there? If not Anglesea. (Not sure about JAE yet.