6 replies to this topic

[Kerrin]

My dad's Mk 1 Escort is fitted with jenvey throttle bodies with injectors from a rover 620.

D3184GB

They also seem to be Mini MPI injectors.

Anyone know what the CC rating is.

Cheers

*Please help because the damn car is stuck in my garage and The mini is outside*

Edited by Kerrin, 31 March 2008 - 11:37 AM.

[mini13]

approx 460cc

[Sprocket]

MJY100460 - 480cc as tested

[Kerrin]

Dammit

I have been on the Zetec forum, The calc for cc is apparently (cc x 5) /4 = max hp

so (480 x 5)/4 = 600hp!!

I think they are too big

something like 200cc would be ample.

How come an MPI has injectors so big I am confused, is it to help with the Siamese ports and quick pulse times or what?

[Sprocket]

The Large cc injectors are designed for sequential injection where there is only one squirt per engine cycle, per cylinder.

These 480cc injectors at a BSFC of 0.5 , fuel pressure at 3bar and max duty of 80% would give an estimated max BHP of 290 when used in sequential. If you are using semi sequential, multiply that by 2, and by 4 for batch fire.

As an example, i am using four MJY10029 injectors, same design as the MJY100460 but almost half the cc. This gives me 145bhp max on sequential injection. The ECU I run can run sequential injection without a cam sync sensor and has 8 injector drivers if i wanted to use them. Some ECUs just have two injector drivers, in which case you would be restricted to semi sequential and yes the 460cc injectors would be too big but the 230cc would be more suited.

What ECU are you using?

The Mini uses these injectors as because of the timing involved, it needs to squirt a lot of fuel in a very short period of time. Also remember its running sequential injection and only two injectors. Yes they are big, and not being used to their full potential, but the way the MPi fueling works, it needs them. At a BSFC of 0.5 fuel pressure at 3bar and duty cycle of 60% (Low because of the nature of the MPi system) two of these injectors are good for a Max bhp of 110, so you can see that the 63bhp Mini, the injectors are adequate but not overly large. However, id be surprised to see an MPi mini with more than 90- 95bhp.

[Kerrin]

Hi

Yes I understand the theory now.

by the way i think i messed up the post above it should be (380cc /5)x4 which is 304 BHP (two injectors on a mini is theoretically 152).

We are running a Emerald ECU with Jenvey Throttle bodies DCOE style. The ECU will drive two injectors per cylinder, so we could go dual and have a more complicated setup but I am having enough trouble getting my head round this one. I have been advised to aim for 80% duty cycle, but with possible future engine mods maybe we will aim for a bit of spare capacity.

I have been advised 310 cc injectors would be more suitable, so will change to them.

[Kerrin]

Update,

I changed the injectors to the new 310cc ones

What a difference. It seems the front two inectors weren't working anyway, the paint had burnt off the rear two exhaust manifold pipes but not the front two, I knew there was something wrong as the wiring for the coil and injectors are paired 1+3 2+4 so it couldn't be wiring.

As soon as it fired up with the new injectors in, the front two cylinders burnt the paint and it zinged like a 16v should.

Hopefully not long till the Mini is back in the garage.