Pinto Upgrade

[ChrisL]

I think you make a good point David T, bikes TBs end up costing more because of all the hidden/forgotten costs.

Re Flow rate, I thought it was simple a case that a bike engine spun twice as fast but had half the capacity so the av flow rate is roughly the same, hence you can use TBs and carbs of a 900 cc bike engine on an 1800cc car.

As for through lengths that just a case of getting the gearing right, i.e. how far from the pivot the cable attaches. Admittedly my set up up bike carbs has a short peddle movement, but I figure it's quicker to WOT, that and I have such finesse as a drive I can control/modulate and the required finer detail

Some interesting points being made though... and I'd be interested to see where Dick (&team) end up

[scotty]

How "bad" are bike tb's at low revs then? If not set up perfect? Annoying or undrivable?

[Dick]

Just to add to the chat lots of bikes now use 2 injectors one for low rpm and then bring the 2nd one in at high rpm the position of the 2 are well apart as well.

[hearntd]

I'm With David T as well to be honest. when I did my swap out I was in 2 minds what to do but you get a complete kit from Webcon and it just works, no extras or hidden costs. And now you can get the Pro 5 so you can still "play" with the settings if you want to.
These guys spend many months setting up the map for each ECU rather than just a couple of hours on a rolling road.
They estimate about 195BHP on a standard Durated and as David say about 175BHP on a stadard Zetec (not to shabby).

[Dick]

Must say plug and play is the easy option and yes what you get will work from the box as you say . But im sure that the map you get is one that has some scope for improvement as no 2 engines are the same even if they are new. Its nothing to do with being tight as I have a complete set of the alpha webcom inc ecu, This is something I want to try and make work as good as jenvy's or better than . I understand the movements required to open the bitb's and the citb's but having driven different kit cars lots of people have no idea about peddle ratios and how they effect the throttle (Q RUSS)
The position of the butterfly in the tube is easy to overcome as is the peddle ratio the issue is the injector im not sure if many people have looked at the many types of injector nozzles that are available and by changing these the characteristics of the fuel system can be changed to suit different cars and im not taking about the flow rate. This is the area we will be working in.
Im hoping to do a back to back test with a car that has been set up with jenveys and an omex 600ecu if I can I will put the results up be they good or bad

[russtik]

...people have no idea about peddle ratios and how they effect the throttle (Q RUSS)

I have some idea Just wasn't sure what to do about it

I have to say I'm finding this thread pretty interesting so far and intrigued to see the results of Dick's experiments. The only point of reference I have to this is the Jenveys on my (Zetec) Tiger and I was very happy with them. My SR2 is a turbo set up but if I was going to build something my first choice would be a Duratec with ITBs so this discussion is on the money.

[Fury1630]

If the car TB's manufacturers started with a clean sheet of paper and designed the car TB's, why did they end up with what they did? They didn't end up with something that looked like bike TB's.

They didn't - they started with a Weber twinchoke & modified it incrementally. The direct-to-head ones are probably a clean sheet design. Personally I don't think there's as much science in it as people think. With a carb there was science aplenty as the choke size had to be optimised to have a high enough flow rate at idle to pull fuel through the jets (no fuel pressure in a carb remember), but not be restrictive at WOT. With injection it's all about smooth flow into the cylinder, so while you don't want steps & angles, the flow rate through the TB is much less critical because the fuel will be squirted in whether it likes it or not. There will be gains to be had by playing with the details, but many cars run just fine with one injector in an inlet plenum.

I've never understood the theory that BTBs "designed wrong for cars" it's a tube with a butterfly in it, there's not a lot to design really. I'm sure the Jenveys are much highter quality & that may be the difference, equally there are some quirks with some BTBs like the GSXR where the cable drives a shaft which drives a spring which drives a shaft which drives a spring which drives a shaft which drives a spring which drives a shaft which DRIVES THE THROTTLE POT, so the ECU only finds out the throttle's been opened after all the butterflys have started moving & No.1 could be some way open when that happens - so that may make them difficult to set up if it's not engineered out.

Also with BTBs folks invent thier own throttle cable set-ups & that's not as simple as it appears & it's at low throttle that any problems will show up, it took me a couple of iterations to get it working right.

As I say I can definatly see the advantage of the fit & forget, everything in a box set up, but I wanted to fiddle with the details, I also had space limitations which made jenveys look iffy & it's a lot of money to spend only to find you can't fit them in the space.

You pays your money etc.

Dick, if you want to see what I've done I'll be at Brands on Sat.

[Pistol]

Agree with Tony, the parallel TB are made to put the air filter in exactly the same place as it would be if using carbs. Direct to head TB look much more purpose designed and result in having a very long inlet track/trumpets.

While speaking with a fellow WSCC member, I have been advised that if converting from carbs to FI, there is no reason to run a return fuel line from the fuel rail back to the tank. Most production cars now now just bleed the excess fuel off straight after the HP pump - so in a westy that can be all performed in the boot

[Dick]

Please understand that we are taking on-board every thing that is being said and we have spent a lot of time resourcing this, its something that we want to make work not for financial gain but more for the oh it cant be done when all you need is vision and time with patients to work it out. If any one has photos or any info that can help us out then please forward it to me .
Please remember we are talking injection and not forced induction or carbs as these are a different ball park

[David T]

If the car TB's manufacturers started with a clean sheet of paper and designed the car TB's, why did they end up with what they did? They didn't end up with something that looked like bike TB's.

They didn't - they started with a Weber twinchoke & modified it incrementally.

I did think that about mine, but forgot to write it. It also explains why the whole mechanism that converts the motion of the cables to the motion of the butterfly spindles that is on mine is the same one that was fitted to the twin carbs in the past. The pairings are also reflected in the twin K&N style filters.