Technical seicento on bike tb's (question)

[madmike87]

hi all just wondering if anyone has done this? i would love to do but would it work on a standerd ecu or even gsxr carbs or something?

any help would be good

oh my car is the spi so i also need help with what i need to swap it to mpi

cheers mike

 

[clock34]

spi - mpi just splice the wires from the four injectors you use onto the two wires origionally there. there batch fire so it works

 

[craigb244]

but itbs are only any use on very lumpy cams... cams which would need another ecu to run.

you could fit itbs on and maybe bodge the ecu to work but it would be a huge waste of money and most likely loose power and be crap to drive

 

[madmike87]

sweet, what inlet fits? without grinding the head for injectors

so its pointless even trying to put them on with itb's

cheers for the help

 

[Todger182]

Punto 75 inlet fits, but I think the inlet ports on thd head are round so wouldnt it effect the spray pattern of the P75 inlet?

May be cheaper and easier to get hold of a punto 75 engine and sell the bottom end.

Would a 75 cam with a vernier be able to run the itb's?

Thanks.

 

[jimbro1000]

hi all just wondering if anyone has done this? i would love to do but would it work on a standerd ecu or even gsxr carbs or something?

any help would be good

oh my car is the spi so i also need help with what i need to swap it to mpi

cheers mike

Yep - done that, on an 8v engine and a 16v engine. In both cases used a set of hayabusa throttle bodies. The inlet manifold had to be fabricated as the throttle bodies are fitted through flexible bellows and clamped in place instead of the usual nut and bolt setup that most people expect on cars.

It definitely wouldn't work with the standard ecu and provide any useful advantage over a well tuned single body setup.

As already said above to convert to mpi you just cross wire the injectors to fire as a batch. Without some very clever engine management and high engine speeds there is almost nothing to be gained from sequential injection (proven a long time ago).

The 16v engine did run a modified cam profile but not significantly different from standard and no vernier pulley there (pointless on a 16v). The 8v engine is another matter - very aggressive cam profile and a vernier pulley is essential.

 

[craigb244]

Without some very clever engine management and high engine speeds there is almost nothing to be gained from sequential injection (proven a long time ago).

off topic but I do not agree with that, I ran batch on my megasquirt which was fine, then I went sequential, idle became super smooth gained a good few extra miles per gallon, boost came in quicker/smoother. basically everything under 3500-4000 rpms became a lot better. (anything above was unchanged as valve open a close so quick that timing does not matter from what ive read/felt)

 

[madmike87]

so its pointless even trying then without aftermarcket ecu

cheers for your info though

 

[jimbro1000]

off topic but I do not agree with that, I ran batch on my megasquirt which was fine, then I went sequential, idle became super smooth gained a good few extra miles per gallon, boost came in quicker/smoother. basically everything under 3500-4000 rpms became a lot better. (anything above was unchanged as valve open a close so quick that timing does not matter from what ive read/felt)

Then I would argue that you didn't have your batch firing set up as well as you thought you had. I've had long discussions on this matter with some of the country's top tuners and they all had come to the same conclusion. The only caveat on this is that has been several years since I last investigated the subject. I certainly agree that on paper it should be better but actually finding those gains was proving very hard and when they were found the gains were not as significant as we would all like.

Typically idle is on a closed loop system so provided the lambda sensor is working and the ECU has correct readings it is pretty much self managing.

 

[craigb244]

running batch was fine. im just saying it turned out better with sequential
i have rather large injectors and have them timed to shoot all the fuel it needs before the valve open.took a while to find the sweet point

kritip has the same (even has sequential ignition) and he said it was much better too