I'm working out the requirements to inject a V12 jaguar, using bike ITBs, and an extraefi suirt.

The inlet ports are 34mm, the sweapt volume of each cylinder is 442 cc, about the same as a 1.8L 4.

Is there any point having TBs with a bore larger than 34mm?

Also what are the popular TB's to use on 1.8 4's, I'll need 3 sets from 4 cyl bikes.....

four sets from a speed triple then

Any 600cc should be well upto that.

Thats going to be fun ballancing that lot

As usual my ears prick up with the mention of Jag v12

Il be watching this thread as it may come in handy for a future project

May i ask what project this is for?

Simple answer is no theres not any point in having TBs with bigger butterflies than 34mm.

To be honest most bike throttle bodies are 36-42mm so any of the common ones will be fine. I would just go for what is readily available and cheap.

Thanks guys.

Its the next project, the new owner drove my Zetec MGB away this morning, with a massive grin when the rear end let go when he changed up into 2nd.

I'm off work next week and the objective is to find a V12 2+2 eType, got 6 to look at and about 1500 miles.

Not a locost car, but the performance mods will be.

Not tempted by the magnificent sound of 6 webbers then? Kits available off the shelf...

I worked on a Jag V12 with these once - fantastic

Extremely tempted, but at two and half gand...

Its cost me a new kitchen to get approval to buy the car...

How about early GPz 1100 TB's ? Cheap , easy to re-space (I've done loads for crossflow's) , and about 35mm choke ?

That is going to be awesome. I assume you have seen this site and thread. TBI details link
It might be useful for deciding your TBI's.

If you go the "standard" GSXR600 route, then you need to be aware that the 4 TBI's are different to one another (actually the middle two are equivalent), so glueing into 2 rows of 6 will require 4 sets of 4 as the ones with the TPS are different to the others.

Regarding balancing. I think it would be easiest if you have the throttle link near the middle of the row of 6, but as stated you will require a few minutes to get it perfect.

Please post some photos as you go along.

Matt