budget throttle bodies management

ime sure ive seen a bmw with this setup in a scrappy?

 

golden's idea seems like a good way of combining a linear throttle pot with a rising rate linkage to allow you to get better driveablility at part throttle


also - if you could use the GSXR ecu with the GSXR throttle bodies would it be possible to *double* the speed input? so the ECU reads double actual RPM - that way the ECU could believe it was revving to 14k, when in fact the engine is doing 7k, this way you would have twice the sensitivity through having twice as many RPM sites?

or how does this sound - use a throttle pot with an ecu working off the manually operated butterflies, then a seperate ECU with a map sensor to control the secondary butterflies - just a very simple closed loop system that aims to keep a fixed vacuum in the throttle bodies for up to (for example) 50% of throttle opening (taken from the manually operated butterlies throttle pot) then progressively open the secondary butterflies in line with the manually operated butterflies once the manual ones exceed 50% opening?

if you wanted to be really flash you could even make the secondary butterflies *track* the manual ones faster at higher revs than at lower?



OR...


plug in the suzuki ecu so that it has all inputs connected (with the 2xrpm input) but only connect the outputs that control the secondary butterflies - then use the standalone (pug) ecu controlling the injectors, sparks, and getting a throttle pot and true speed input

that way the suzuki ecu *thinks* it's controlling everything, but will in fact only be running the secondary butterflies, while the pug ecu will run the engine and be *unaware* of the existence of the secondary butterflies.


have i bored you yet?

 

no more than usual dex

tt

 

I think that would simply be a case of cutting another gap on the crank speed sensor wheel. That way, 2 gaps would pass the pick up every revolution rather than one, giving the impression that the engine was turning twice as fast.

 

This could alos be done eletronic fashion that wouldnt need much.

 

What about this - its dead simple and wont cost a penny ...

Put baseball cap on at a slant

Tighten 6 point harness

And just blip the throttle and slip the clutch for that loverly noise !

 

Fair one

 

The control algoythms for electronic throttles are very complex indeed gents and besides, why do you think you need it? The 'Suki has it because with the size of it's ports and the cams it runs if you wind too much throttle on the power disappears and that leaves the rider trying to balance the bike on a throttle that it not linear in its operation. The electronic throttle essentially keeps the throttle partially closed even though the rider has it fully wrung. DBW throttles do feel a bit pup so Suzuki have decided to keep the 'feel' by having a 'real' throttle but ECU intervention keeps the motor from bogging down at low rpms with too much throttle on. Best of both worlds.

To 'double' the speed you would have to double the whole crank image. So if it is a 13-2 format toothed wheel you would have to make it a 26-2-2 with the two gaps opposed. Trouble is the transients would be all to cock in the ECU and it is very unlikely to be on a regualar type of EPROM and is most likely to be on a bespoke microcontroller, emulating which will be very difficult if possible at all.

Just get something that is known to work and save youself a whole heap of grief and wasted dyno time- it's not cheap you know, a couple or three hours wasted and you could have bought some shiny new throttles.

For a 16v motor, you might just want to check out some E36 M3 items..... plentyful, cheap (they do blow up) and they'll fit better than the Suzuki ones by a heap. I once heard that VW motorsport used M3 throttles on their F2 rally cars....

Once again- 'Parts left out cost nothing, weigh nothing and can never break' they don't need complex setting up either......

 

You can't use the suzuki secondary throttles to control idle as the fit in the bore is not good enough.
Bikes use them to control power delivery in lower gears and improve driveability by slowwing down throttle response.

Best to throw the secondary butterflies away and rely on throttle quadrant progression. If off idle operation is a bit lumpy due to large throttle angle changes, generally there isn't enough TPS sites around idle to give good definition (either due to poor resolution on input to ECU or bad setup of sites as Mr. Schofield suggests) or spark tables ramp in too fast or fuelling jumps around too much (Down to calibration - Mr. Schofieldis quite right about the worth of quality calibration time).

My guess is that most bike throttles would be OK though- remembering that bikes are MUCH more sensitive to light throttle openings than cars due to lack of flywheel inertia and the increased likelyhood of falling off int he engine has a bit of a cough....

Bikes do use both MAP and TPS as the load inputs to the ECU though, but the MAP sensor should be included in the throttle body setup so you should be able to set that up in your ECU calibration, esp if the throttles stick out forwards like that too as there are lots of turbulence issues sticking them out in the airstream like that (Good ones though if you can account for them in the calibration)

 

Great write up mk1 - can you now do the same for a VR6 please? Cheers.

 

VW used modified M3 bodies on the MK3 kit car. They are really nicely engineered. I looked at using some E30 ones on the Polo but the spacings were too wide. With some butchering they would have gone on though. The spacings on the E36 may be different - not sure. I know someone who runs them in a really horrible Datsun.

 

How many peeps have just joined the m-power forums?

 

these look cheap with the exchange rate at the moment
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd= 1&item=7939604737&category=46098&sspagename=WD2V

 

can a mod please make this a faq with a link to this thread?cheers

 

Bikes use Alpha-N or, simply put throttle angle v rpm, as the primary load reference. The MAP is only a correction device, mainly to account for a little ram effect at the high speeds they can attain. BTW Dynamic pressure in Pascals is 'half x rho x (U squared)' where rho is the density of air in kg/m cubed and U is speed in m/sec for those wanting to know how much affect 'ram air' has. In a perfect world it's around 4% increase in pressure at 200mph, which many bikes can do these days, so that pressure has got to be taken into account for this fairly considerable variable. MAP is not used as the main load reference because there is simply not a strong enough vacuum signal with throttle bodies, typically as low as 5" hg, which leaves little scope in the way of achieving good load definition, especially at low engine speeds.

Bike size motors, giving bike size power, run with much larger relative throttle openings at low rpms due to the very volumetric efficiency, and therefor low vacuum, low down the range. They are also much higher geared than cars, relatively speaking (how many cars do 70+mph in first?), they are thus much less sensitive to throttle openings low down. If this wasn't the case I am pretty sure the chaps at Suzuki and Honda would make the throttles a little differently as a little dicky bird told me that they actually do know what they're doing!

The sites can be bunched up in most ECUs around the closed and off idle positions to give better definition in that area but why make any compromise at all when a simple, mechanical, tweak will have it hunky-dorey? The transients are also more difficult to get right, thus taking more time, costing more money.....

E36 throttle centres are at about 93mm port spacing. The ports are oval and 27x51mm. The plates themselves are 46mm. The TPS mounts on the actuation shaft on the E36 so its opening is initially faster than that of the throttle spindle itself. The port has a downward bend between the throttle plate and the head face of about 25deg. The port axis is at 90 deg to the head face at the flange.
E30 throttles are at about 101mm centres and are of slightly greater area, but are a bit of a queer shape. They are straight, give or take, and the port axis is not at 90 deg to the port face but about 30 deg downwards as the port face is vertical. The throttle switch, which can easily be replaced by a TPS is directly on the throttle spindle, unlike the E36.

It's not a Datsun any way, it's a Nissan. The same as the fastest four pot car in the world with it's 7.7sec 1/4 mile!

At least it wasn't named after a silly game that plonkers like Prince Charles play!

 

great info once again Wayne

 

Yup, straight line cars! Yours is about as quick as the budget at the minute though eh!

 

hows the polo coming along nick?

 

Erm, slowly. Six weeks off work and a Government grant into the Needy Nick fund would help. The engines together and sitting in the kitchen with the box, so thats a step in the right direction. Target date is Easter.

 

Hi guys this is my first Post on this forum.Ihave a 1.4 16v Lupo i plan to do this sort of Tb conversion in the future. After reading threw the full post over and over i think th cheapest solution other than a set of jenveys(sp) would BMW E30 M3 S14 Throttle Bodies?Orif im willing to put up with a ruff ride i could go for some bikes ones? Ivcompiled a list of what i think ill need to get the car going properly:



Tb's off some sorta high end bike ie GSXR600 THROTTLE BODIES INJECTORS gsr1100 etc orBMW E30 M3 S14 Throttle Bodies
Custome Exhaust system
Decent Manifold
Intlet manifold adaptor
Old Pug ecu and loom to connect the ecu(magnet marelli 8P)
Front crank trigger wheel(pulley)60-2 of a V*uxhall 1.4 mpi engine(astra/nova ect)
crank sensor from the same V*uxhall
Temp sensor,found on a variety of cars,metro,escort,mondeo
Coilpack
A couple of relays and holder,found on a mk3 polo


Am i headed in the right direction?





Paddy
Edited by: LupoSport