If you look down at the turbo and wastegate actuator you will see a pipe coming from each, up to a T-piece If you follow the rubber pipe from the T-piece up towards the rear of the engine bay it plugs on to a solenoid. Pull this pipe off and there is a plastic grommet/sleeve/restrictor. You will need a sharp thin object to carefully prise it out, be careful not to loose it as it is very small. The other pipe from the solenoid goes to the intake pipe. I would only recommend removing the grommet if you have the Sport ECU as you may experience fuel cut when OAT is low. This causes a lot of stress on the engine.
there are several threads on this, I think claudius started it all, but then got his nuts chewed because it induces fuel cuts (i think). not an expert but i think the general oinion of those in the know is..don't touch it.
I am sure that you will have some replies giving you the true facts.
For some reason the E6 gets the fuel cut but not overly sure its just gromet removal as other have it with gromet still in.
I have had mine out on my E4 for 2 years and no problem at all.I have a decat exhaust and blitz filter.
and the perameters of the E4 ecu are far less than that on the 6.its a case of try it and see,but nocible increase in accelaration from a p!ssy plastic gromet.
I used to get fuel cuts with the grommet removed but I also have a HKS Hyper Muffler with the GT extension kit, ie. the whole exhaust system. If you remove it with the std exhaust on, no pbs. Best is to have complete exhaust, grommet removed, Sports ECU and boost controller.
If you remove the grommet you will have more booost pressure, but you can have fuel cuts also with the grommet.
The ecu use the fuel cut when the boost pressure is above 1.3/1.4bars, and if you have a special exhaust and air filter fitted the boost is already higher than std, so when you remove the grommet you get the ecu limit.
Another reason can be the wastegate that is damaged and this raises the boost.
Fit a boost gauge so you will know if your boost is too high.
'Before the removal I had a peak of 1.27 boost, after 1.35...no fuel-cuts till now.'
Are you getting fuel cuts now?
If you are then put the 'grommet' back in, don't live with fuel cuts they will destroy your engine. Not only are you putting great stress on the engine but it is well documented that upgraded con-rod bolts are needed for that sort of boost level and that is even before you take into account possible fueling problems.
I am afraid if people have to ask what the restrictors do then they shouldn't even think about touching them. 'A little bit of knowledge is a dangerous thing'.
removing the grommet will give higher boost
removing in-line restrictor will reduce it again, so obviously a smaller hole in the restrictor (as vell as grommet out) will give more boost,but this will probably get you into fuel cut problems.
remove grommet and try,some cars cut ,some run for months without problems
hh,i for one am not convinced about the conrod bolts,as are many others.
Surely better to err on the side of safety with the con-rod bolts? I think there are too many knowledgeable people and companies saying to upgrade the con-rod bolts to dismiss it completely.
Some cars can run for months without fuel cutting because the cut limit is related to air density which varies with the weather, temperature and height above sea level etc. (also each car will have a slightly difference set up). In summer when the temperatures are warmer the air is less dense and you may be cut free for a while, when the temperatures drop in winter then the air is more dense and fuel cuts may occur. I got the occansional fuel cut below about 12C-14C with a completely standard E6 until I sorted the restrictor out as it was overboosting. Don't even think of touching the restrictors without a boost gauge of some sort fitted.
Basically I don't tell people how 'modify' the restrictors because I would hate to have it on my conscience if someone destroyed their engine due to fuel cuts after I told them how to do it (and believe me you can kill your engine through fuel cuts).
As I said I was getting a slight overboost situation that resulted in the odd fuel cut. I worked out how the Boost Control system worked on the Evo with the help of some books as I wanted to know exactly why and how it works rather than just to be told how to do it.
I even wrote a 2 page article on how to 'correct overboost' with a complete explanation of the Evo Boost Control system (including diagrams) but I decided not to submit it to the MLR magazine as it was too easy for people to go the other way and raise the boost which wasn't the point of the article.
I am not saying people shouldn't touch the restrictors at all its just that when someone comes on here and asks 'How do I remove the grommet?' then people really should explain all the possible problems associated with it and then let them decide whether they think it is worthwhile doing it.
I know some people have said about fuel cuts above but only really CliveW came up with the best answer I would only recommend removing the grommet if you have the Sport ECU as you may experience fuel cut when OAT is low. This causes a lot of stress on the engine.
Even one fuel cut is a fuel cut too many in my book.
When I was experimenting with manual boost with the grommet removed and a 0.9 restrictor I was boosting to 1.6 to high ,replaced the grommet and I was boosting 1.4 ish.What you have to watch out for is that every time you improve and modify your induction it raises your boost.A electronic boost controller makes it easy to programme boost to suit current mods.I believe from my experience its the best way to go.
There are also some good mechanical boost controllers on the market which are easy to fit and adjust and allow you to control peak and held boost, oh and they are about a fifth of the price of an electronic boost controller. Also for the price of an electronic boost controller you could buy a programmable ECU, eg LINK, which has a boost control function in itself.
I went for the Apexi Boost controller £450 and I believe its the best there is.With a sports Ecu ,uprated fuel pump,and FSE Fuel regulator you can run 1.5 bar safely .Give Clive a ring at RC Developements 01925 575 290 he set up my car ,he is very knowledgeable and will always be happy to give advice I trust him with my new TME and theres many I wouldnt.
Clive is not wrong in what he says it is a matter of taste and what you can afford.WE all have our own ideas on tuning and I would never say Im an expert because Im not.I just listen,research ,and form my own opinion ,I have learnt a lot from this board and will continue to do so.
I agree with Clive and HH6 that gromet removal is best not done on its own, there are plenty people who reported fuel cuts after doing this and at least one person who has needed a replacement engine very probably as a result of this. I did not remove my gromet after hearing about the risks but got fuel cuts anyway gunning it on a cold wet night in March with a decat exhaust as the only mod at the time! (see Wazuptommi's comment about breathing improvements upping boost).
Best way to go IMHO is to have a remap or aftermarket ECU in conjunction with modification of the restrictor to get the desired level of boost. Removing the gromet costs nout, but the cost of a bent conrod is thousands.
I did not have any fuel cuts after the grommet removal, but I got sort of scared anyway...
Soon I will go for an aftermarket ECU and prob. an EVC. I think I will go for the RALLIART Sports ECU, bc here in Germany it is not easy to find someone who really knows to programm a re-map ECU.
Anyway, I still have some questions.
1. The grommet is the little plastic cylinder in the solenoid (right?), but what is the metal pice in the tube?
This pice restricts the flow much more than the grommet it self? When you are talking about grommet removal , are you just talking about the plastic pice that sticks in the solenoid?
2. Is the Sports ECU plug and play ? Can you recomand it with the HKS racing suction kit and just a de-cat original exhaust?