Throttle Body

Post by **Shug** » Tue Jul 25, 2006 1:21 pm

GregR wrote:pah - I wish he always beat me soundly with a halibut, round the buttocks

[awaits comic replacement of "off" for "to it"]

What?

GregR · Post by **GregR** » Tue Jul 25, 2006 1:23 pm

Shug wrote:
GregR wrote:pah - I wish he always beat me soundly with a halibut, round the buttocks

[awaits comic replacement of "off" for "to it"]
What?

proper tea laughed down nose moment there

mac · Post by **mac** » Tue Jul 25, 2006 1:24 pm

Personally I was thinking along the same lines - not a technical though - but I know to cure the surging I should go onto to dthtb's but that requires a full remap of the ecu or an emerald both of which double the cost

worth a try

Post by **Shug** » Tue Jul 25, 2006 1:30 pm

mac wrote:Personally I was thinking along the same lines - not a technical though - but I know to cure the surging I should go onto to dthtb's but that requires a full remap of the ecu or an emerald both of which double the cost

worth a try

/dons parka for geek mode

What's happening is that because there is a volume of air after the TB, that the valves can move (wilder cams, so valves making wilder movements) they build up resonances and pulses in the plenum. This means the MAP sensor is seeing a constantly moving target and that the air going past the injectors does so in a pretty erratic fashion. It smooths out when the throttle opens a bit, as there's no standing air to resonate.

DTH TB's remove this big slug of air, as the butterflies are mere centemetres from the valve heads. Obviously, they also flow much more air, much faster giving better top-end power, but that's why they help the idle

/toddles off to sadgiffers.com

mac · Post by **mac** » Tue Jul 25, 2006 4:58 pm

Ptp are suggesting that the fitting of verniers will help with the part throttle issues that I have - they say the 52mm might help but that they prefer the 48mm.

Mac

Post by **Shug** » Tue Jul 25, 2006 5:00 pm

mac wrote:Ptp are suggesting that the fitting of verniers will help with the part throttle issues that I have - they say the 52mm might help but that they prefer the 48mm.

Mac

You know how much verniers cost?

Believe it or not, you know who also has a set (in a spare engine)

Tho, TBH, I'd rather keep them and you'd be better off with shiny new ones anyway....

mac · Post by **mac** » Tue Jul 25, 2006 5:01 pm

Yeah - in there reply was a link to the page selling them!

Mac

Post by **Shug** » Tue Jul 25, 2006 5:03 pm

mac wrote:Yeah - in there reply was a link to the page selling them!

Mac

They are likely right though.... Pikey version is to work out how much you need to move the cams and do a mod on the standard pulleys to rotate it exactly that amount....

DVA's K series page gives a good guide to doing this if you're brave.

Rich H · Post by **Rich H** » Tue Jul 25, 2006 5:05 pm

I'm going to need verniers too...£160 + VAT FFS. I'm exploring the options for modifying a couple of standard ones I have knocking about...

Post by **Shug** » Tue Jul 25, 2006 5:09 pm

RICHARDHUMBLE wrote:I'm going to need verniers too...£160 + VAT FFS. I'm exploring the options for modifying a couple of standard ones I have knocking about...

From what I remember - it's actually quite simple to use the standard ones. You just remove the woodruff key (as it's not really what the camshaft drives off, it's the clamping force on the bolt that attaches the pulley)

So, you can then rotate the cam and clamp the pulley at the right point. It's just not as easy as doing it with verniers, as you have no reference to how far you've moved it (therefore how to go back to square 1)

DVA's page wasn't loading for me there, but it's all on there.

Rich H · Post by **Rich H** » Tue Jul 25, 2006 5:11 pm

He has offset dowels to replace the role pin, no woodruff here, that's the crankshaft....!

My plan is a little more involved than removing the pin (Of course!) and will hopefully be a bit more accurate.. Will keep you updated if I ever manage to get it sorted out.

Victor Meldrew · Post by **Victor Meldrew** » Tue Jul 25, 2006 5:11 pm

Shug wrote:
mckeann wrote:the bigger throttle body will make your drivability issues much much worse. Basically, for the same throttle opening at the peddle, the TB will flow more air, and the car will be even jerkier when just trying to manouvere slowly or in traffic jams.
Unless the slow speed mapping is overfuelling like a b'stard. Either it could do as you say, or the increased airflow will damp down the pulses from the bigger cams in the plenum and give the MAP sensor a more stable signal to work with.

It's worth a try, as the fuelling will be varied by MAP sensor as the PTP uses a piggyback ECU - so the MAP functions of the standard ECU are still trying to read pressure from a manifold that's now filling with pulses from the harier cams....

I will be fitting a 56mm thottle body in the next few weeks.. I know it may be a little more interesting at slow speed but it wont cause any fueling issues that could damage to the engine will it?

Ok I want a little more umph and one that doesnt stick but I dont want knack the engine.

Post by **Shug** » Tue Jul 25, 2006 5:16 pm

John Reid wrote:
Shug wrote:
mckeann wrote:the bigger throttle body will make your drivability issues much much worse. Basically, for the same throttle opening at the peddle, the TB will flow more air, and the car will be even jerkier when just trying to manouvere slowly or in traffic jams.
Unless the slow speed mapping is overfuelling like a b'stard. Either it could do as you say, or the increased airflow will damp down the pulses from the bigger cams in the plenum and give the MAP sensor a more stable signal to work with.

It's worth a try, as the fuelling will be varied by MAP sensor as the PTP uses a piggyback ECU - so the MAP functions of the standard ECU are still trying to read pressure from a manifold that's now filling with pulses from the harier cams....

I will be fitting a 56mm thottle body in the next few weeks.. I know it may be a little more interesting at slow speed but it wont cause any fueling issues that could damage to the engine will it?

Ok I want a little more umph and one that doesnt stick but I dont want knack the engine.

Shouldn't, as it's still using MEMS management.... If it runs, the MAP sensor should adjust for the extra air. Might be tempted to check the plugs a couple of times (hot) a wee while after fitting, just to be on the safe side..... Even better would be a double-check with a wideband lambda kit.

You sure the opening in the plenum is big enough for 56mm? It probably is, I've not looked at one in ages - the standard TB has a venturi shape, doesn't it?

Post by **Shug** » Tue Jul 25, 2006 5:20 pm

RICHARDHUMBLE wrote:He has offset dowels to replace the role pin, no woodruff here, that's the crankshaft....!

My plan is a little more involved than removing the pin (Of course!) and will hopefully be a bit more accurate.. Will keep you updated if I ever manage to get it sorted out.

D'oh

You got what I meant though..... Been a while since I read it!

Victor Meldrew · Post by **Victor Meldrew** » Tue Jul 25, 2006 5:22 pm

Shug wrote:
You sure the opening in the plenum is big enough for 56mm? It probably is, I've not looked at one in ages - the standard TB has a venturi shape, doesn't it?

Might not be but its the alloy VVC one so I have some scope to open up the inlet a bit and smooth out the flow as best I can.