Adam M

If I recall correctly my car has never made anywhere near 350bhp, and will never make near 350bhp.

My comment was a dig at the 350bhp boys, one of whom I am not and never will be.

Homer Simpson

Edited as requested by Adam

[Edited by Homer Simpson - 28/05/2002 14:17:32]

dowser

Surely, the risk of fitting injectors that are too big are that your low rev/load spray patterns will be horrible and fall straight onto the manifold....?

At what point is it sensible to be looking at a 2nd injector? Spurner - are your 740's really OK on idle/low revs/load now?

Richard

Adam M

richard, a second injector?

do you mean a fifth?


homer,

thankyou for editing, I appreciate it. If you want to know what that was all about, mail me offline and I will be happy to tell you.

[Edited by Adam M - 28/05/2002 14:26:10]

dowser

Adam - no, a 2nd....per cylinder

Richard

Adam M

8 injectors sounds like overkill to me.

If you dot he calculations, as simple fifth injector in the central plenum makes an enormous difference and is sgnificantly easier to control/wire in.

To my knowledge even the M48pro cannot run 8 injectors, dont know about gems etc, but I suspect not.

You are talking M800 or pectel T6 money to control that kind of thing, whereas a fifth injector can be controlled by a simple home made add on gizmo.

I might add, that the simple gizmo is beyond me, but I know pat could be persuaded to make one if necessary.

R19KET

Richard,

There will be VERY few people who will actually "need" 740cc injectors.

Trout could safely run 550cc's, and still be getting circa 85% idc.

Spurner's example of 50% idc on a 740cc, equates to about 85% on a 440cc injector, or 68% on a 550cc.

Idle on big injectors will vary car to car, and will also depend largely on how good the ecu is.

Adams suggestion of using a 5th injector, similar to the old RA's is a good alternative, but it's probably easier, and as cheap (in the long run) to just fit 550cc's.

Mark.

Mo

Adam,

I was on about running 380s with a TD05 and cr@p slanted intercooler. Mine is OK upto 1.2bar but struggles with anymore.

I believe that Andy was running 380s on his RA with no real problems (other than his urge to run more boost than a Scania!) I was wondering if this was to do with his fuel rails. Hence my post on 22B.

Adam M

andy has the early ra with 5 injectors though, which surely must explain how he can run the extra boost.

It also makes his achievements of performance on less than £1000 more difficult for tohers to replicate!

David_Wallis

Dont count on it... Im going to beat him

David

dowser

Thanks Mark,

When you say clean idle will 'depend largely on how good the ecu is', do you mean it must be fast enough to react to the imminent stall it's seeing? I assumed the issue would just be that there wasn't enough airflow to atomise (is that the right word?!) the charge correctly.

And....a 5th injector basically needs to be fired every cycle and the spray thrown in the right direction - I'd have thought 2nd injectors would give much better control. While harder to mechanically fit and align optimally, I guess the elctronics wouldn't be that hard to engineer (WOT above 3.5k, for example). Or am I just being inane? Or, more likely, not wanting to admit that Adam may be right

Richard

spurner

Katana, the 740's were ~NZ$330 each. They wouldn't fit the older style injector rails, but I picked up some v5 ones for NZ$100 which were fine.

Dowser, the 740's really are okay on idle, and low rpm response is awesome. Getting off the line is bit of a mission at times, but that is more to do with the lightened flywheel and a clutch from hell(think it's either on or off).

Katana

Cheers Spurner. A bit too expensive for my pocket. I'm a student.

R19KET

Richard,

Some ecu's have better granularity, and react more quickly to change than others.

Like Spurner pointed out, most things are achievable, with time, but I don't know which ecu Spurner uses, and it may cope better than others.

Using 8 injectors is a very nice way to control the fuelling, but it's a LOT of work, expensive, and as Adam pointed out, very few ecu's have the ability to do it correctly. As for bringing in the second set, commonly this would be done on IDC/IPW, not rpm.

Using a 5th injector really isn't that bad. It's mounting position is important, but since it was fitted as standard on the early RA's, and seems to work pretty well on Andy's car (Cosie Convert) it's not a big issue.

Whilst Pat could make a 5th injector controller, there are various "off the shelf" options available. One of them being the ERL MF2 controller.

You haven't said what power you've got, or are aiming for, and unless you are intending to go internal, and run in excess of 380bhp, 550's should be fine, and if they are marginal, increase the fuel pressure.

Mark.

dowser

Cheers Mark.

I won't need to worry about this issue for a while yet

Richard

ric

I am running my MY98 (Uk-spec) with the OEM ECU and fuel cut defender and a Dawes at 1.15bar boost (VF23 turbocharger and exhaust system).

The car goes really well, but I think it is on the limit of the fuelling, as you can see brown on the exhaust tailpipe and before I used to get black.

Do you think, by upping fuel pressure by 0.2bar and fitting an upgraded fuel pump I can go up to 1.3bar of boost?

thanks for any information
ric

R19KET

Ric,

I suspect that the 380cc injectors are just too small. An uprated pump "may" help, and a .2bar prssure increase will be very marginal.

IMO, if you want to run 1.3bar, you would need an uprated pump, and 440cc injectors, to be safe.

Mark.

Adam M

I like your fuelling tester!

I am going to do away with wide band lambda and fit an exhaust dirt colour gauge! wicked

Very seriously, I wouldnt want to go to 1.3 bar on a standard ecu.

the standard map cannot be fuelled to anywhere near that boost on a standard turbo, never mind on a vf23 which flows so much more!

the fuel pump is a good idea anyway, as it willprovide the fuel that is expected. You may find the car improves with that at current boost.

But to blindly up the fuel pressure and hope the fuelling will be right is seriously optimistic.

for the sake of all these mods, I would rather go with a link and a gems, and bite the cost of the extra. Your fuelling will already be way out as it is.

You could extract so much just by getting a proper map in there that is meant to deal with your turbo, which your map isnt. You will be spooling up much later than it should be, and starving it of the gas it needs much earlier than it should be, effectively narrowing the useful range of you turbo.

Get yourself a secoond hand link, or save for a gems, is all I can suggest.

ric

Thanks for your answers.

I know that fitting a Link would be the best way to go. But there isn't a mapper here in Switzerland.

There is a company in Germany that maps the Unichip for Scoobs.

Or I could come to UK to have my car mapped, but a Link mapped with everything is VERY expensive. Maybe PE can map my car with the OEM ECU - I think they are able to map the MY98??

My aim in future is to run the VF23 @ 1.4bar.

thanks for any suggestions/help
ric