View Full Version : The Grommit removal question...

06-12-2000, 11:47
I thought I'd post this here too, in case anyone misses it in the other monster thread [img]http://www.ltregister.force9.co.uk/graphics/Wilk.gif border|EQU| 0 align|EQU| middle >

At this point I'll make an offer here...
If someone can knock up a drawing of this bit, showing the internal (hole size) and external dimensions, I'll make a load of these (I've got a machine shop) out of brass with various different hole sizes (again, let me know what you want to try), and supply whoever wants them with a bag containing as many varying hole sizes as you want in each kit . Nominal charge for material and minimal labour only (CNC Machinery...don't ya love it) and you certainly won't have to spend anything like the cost of the Solenoid.
Let me know [img]http://www.ltregister.force9.co.uk/graphics/Happy.gif border|EQU| 0 align|EQU| middle >

Alan (just trying to be a helpful Evo owner...NOT trying to make money here...)

06-12-2000, 21:35
I'm a draftsman so I'll gladly do a drawing if someone gives me the exact sizes - I've got a gromet to look at but no means to measure it (micrometer etc.)

06-12-2000, 22:04
Alan you diamond geezer!
I am a draughtsman, with a grommet and a micrometer!!!! I will see if I can knock up a drawing and save it as a jpg with dimensions to post on here. I have no means to measure the internal diameter of the hole though so if anyone knows what it is and what other sizes they want to try then post them on here. Hopefully I can sort something at the weekend but my Mk1 MR2 is a bit sick so that needs sorting first (It has got upset because I'm selling it and its jealous of my EVO VI!).
Btw I don't seem to have a problem with my grommet removed.

07-12-2000, 13:08
.DXF, .SAT, .IGS, .x_t, .par, whatever, any format can be read this end [img]http://www.ltregister.force9.co.uk/graphics/Wilk.gif border|EQU| 0 align|EQU| middle >

08-12-2000, 09:50
Do you think coordsport will refund me £70 on the solenoid valve? http://www.ltregister.com/graphics/Wilk.gif <!--e3-->

Seriously, I've got the grommet, but have no way of measuring it. Size does matter!! http://www.ltregister.com/graphics/Happy.gif <!--e1-->

I do have the brass jet from the turbo end which I will send to you so you can make some of these as well if you want.

I'm not sure how all this is done, but someone posted about drilling the turbo jet as well as the solenoid grommet. Email me you address and I'll post it tonight nbc66797@glaxowellcome.co.uk



08-12-2000, 10:10
I'll email you the address now.
I can measure the grommit thingy and make from the results.
The IMPORTANT factor here is: what size holes do you guys want in them apart from whatever is standard ?
Remember, I'm only making them, I'm not a tuning expert by any means!
Same goes for the Turbo jet too...tell me what you need [img]http://www.ltregister.force9.co.uk/graphics/Happy.gif border|EQU| 0 align|EQU| middle >



08-12-2000, 11:50
Will heat be a factor in the gromment?
Just asking because obviously the original gromment is plastic (ABS or whatever?) so making a brass one will be effected by heat expansion and thus reduce the hole size?
Mind you I only had a quick look at the removed grommet so perhaps I'm talking B*****ks.

08-12-2000, 18:59
I'd suggest making the restrictors from brass, used the same way as those used elsewhere in the system. That way you will have far more flexibility with the number of sizes, and get finer control......until the weather changes again.

It will be a case of tial, and error, to see what size is best for each car. Guessing that the hose is about 4mm idia', a 5mm brass rod, cut into about 5mm lengths, with a selection of holes (1.5mm~3.5mm) would do for testing.

Or, you could even get a cheap bleed valve, and fit it inline. That way you could start with it fully open, and close it down until you get the right balance. This will always be safe, based on the fact that the worst it can be, is with no restrictor in the first place.

Can't believe I'm suggetsing bleed valves ......wish I'd got a Hotmail acc' before I posted this http://www.ltregister.com/graphics/TooHappy.gif <!--e13-->


09-12-2000, 13:54

My experiences are with an E5 GSR. I am now convinced that the E6 ECU is less tolerant of boost increase than that on the E5. I also think it likely that there are differences in the waste gate and solenoid boost control system that perhaps explain the different results experienced by owners of the E6 when removing the grommet. Grommet removal resulted in a small increase in boost on my car ( and amp;lt;2 PSI).

On my E5 when the solenoid is closed ten pounds of boost will open the stock waste gate. The solenoid lets the ECU “dump” some of the air otherwise supplied to the waste gate. Removing the grommet wastes more air effectively allowing the ECU to set higher maximum boost. A needle valve installed inline after the solenoid will give you very fine control of how much air is thrown away and perhaps let you lift boost only to what is tolerable to the E6 ECU when the grommet is removed.

09-12-2000, 21:02
Practical experience tells me that the E6 ECU will go into fuel cut mode just shy of 1.4 bar

10-12-2000, 22:54
Sorry people I can't find my micrometer anywhere! Hunted high and low today but with no luck. It looks like you have sorted the sizes out anyway so lets hope it works.

14-12-2000, 11:31

Sorry for the delay, but I've been away. I've posted the brass turbo jet to you today. I'm not sure if anyone needs a replacement for this, but if they do I guess you can provide one?

As for the Solenoide grommet, have you got the information you require? (This is the bit I am interested in).



18-12-2000, 13:08
Just posting an update after playing with this grommet thing.

I got the new solenoid valve and sized the internal diameter of the grommet by inserting a 2mm drill (which was a tight fit) into the hole (no funnies please)

I put the new solenoid and grommet onto the car and joy of joys no cut out Although I didn't notice the car was faster when I removed the grommet, boy did I notice when it went back in. Even My missus remarked that her neck didn't feel like it was snapping as I mashed the carpet with my right foot http://www.ltregister.f9.co.uk/graphics/Happy.gif <!--e1-->

Armed with the old solenoid valve, I hunted high and low to find a tube thingy of the right size to use as a grommet. I found that the inside of a used Bic biro was ever so slightly larger (the 2mm drill slid up easily) - Perfect I thought, just enough to max the performance.

Fitted the oid solenoide with home made grommet and the thing cut out!!

I guess I'll live with the £90 hit and put the whole thing down to experience http://www.ltregister.f9.co.uk/graphics/Wilk.gif <!--e3-->


18-12-2000, 22:17
Why drop your car back to stock power? Work around the fuel cut problem instead. Give Dragon a call and get the fuel cut fix.

I spoke with a friend this weekend that says that a voltage regulating diode can be used to limit the signal level produced by the MAS to prevent fuel cut. I worry that this would result in under fueling at high loads but thought I wound mention it anyway.

19-12-2000, 08:16
Is your acr standard?
I only ask because since removing the grommet I've only had mine cut out a couple of times. This is with an APEX airfilter fitted and as such should flow more air and therefore be more prone to fuel cut. Peeley has had his cut out more often but he has got an exhaust as well as air filter. I've purchased one of Dragon's fuel cut defencers but haven't had time to fit it yet (only 4 wires but have been busy drinking at weekend). I think a boost gauge would be a good idea also so that the fuel cut point could be increased gradually using the gauge to set it just above max. boost.

I'll let you all know how it goes over Xmas.