boost

3rd December 2005, 20:50

i have been told by john at gmc that it is possible to turn my boost up myself with out using a rolling road,but need a very long road,he said just to keep an eye on the afr meter and take the mf2 in the car,is this possible,as i think it will be very hard to do

3rd December 2005, 21:42

not entirely sure of the ins and outs of it, but i assume once you've turned the boost up, you then use the MF2 to adjust the fuelling going by what the afr meter is reading.

3rd December 2005, 21:45

Dont know if ur talking about the same thing exactly, but in my mates mk2 golf turbo conversion, he can increase the boost by a twisty thing (lol) its a like a light dimmer!

With me?

can u use that on urs?

3rd December 2005, 22:06

gaf you will need to remove or make the restrictor smaller, or change the bottom pully etc.

With the MF2 its piss easy, just get a mate to drive your car, and watch the AFR and the REVS, if the car starts to go lean on boost, look at teh revs and adjust on the MF2 accordingly until the AFR is showing good.

Since your s/c is linear its alot easier than trying to sort it on a turbo

Do you have 2 injectors?

7th December 2005, 00:32

yes i have the 2 extra injectors,i was thinking about removing the restrictor,but i dont want to run out of fuel.i was hoping toget about 220 at the wheels before it runs out of fuel,what do you think,i do not have dastek on this

7th December 2005, 00:42

dont need a dastek,take it for a run watching the AFR (as said best to do with a mate) write down roughly where the AFR shows in say 4th from low revs upto close to rev limit.

then remove the restrictor, open the mf2, there are 8 potometers (spelling) that you can turn, ranging from 2k to 8k, turning them clockwise puts more fuel in, so with restrictor gone, do the same test watching the AFR, if the car starts to lean out, look at the RPM and adjust it between the 2, ie if the car starts leaning at 4.4k, then adjust the 5k first, if no difference then move the 4k mark slightly, then retest.

Keep doing above until fueling is spot on, if fueling is dropping off higher up the revs you might need to try upping fuel pressure or put a smaller restrictor on etc.

7th December 2005, 00:46

where abouts do they normally put the mf2 as i have never looked

7th December 2005, 01:18

normally stuck on top or to tucked down the side of ecu

9th December 2005, 23:54

what exactly do i have to adjust on here then.

9th December 2005, 23:58

from picture the round white circular things at the top?

10th December 2005, 13:17

thankyou

10th December 2005, 17:28

goo guess

13th December 2005, 16:54

Yes its the small circular jobs that u need to adjust. My MF2 is in with the fuses under the bonnet.

16th December 2005, 19:50

is it true that getting this turned up will just up the power and not the boost,this is what the local performance garage told me.i thought by doing the this the boost would be turned up,had a bit of an argument with him about this

16th December 2005, 20:00

not sure what you mean gaf but you cant jsut up the fueling as it will make the car run more rich. You need to up the boost (remove or make restrictor smaller) then adjust the MF2 to put more fuel in (match boost with fuel)

16th December 2005, 20:05

this local'performance' garage said they cant see how adjusting the fuel and making or taking restrictor out will up the boost,they said it will just up power,i really dont know where they got it from

16th December 2005, 20:22

well the restictor stops the amount of air the charger can pull in and push into the engine, so removing or making the restrictor smaller or removing it allows the charger to pull more air in and compress more. Think of a coke bottle with the small 1cm end but its 5L capacity, if you tip it upside down it takes ages for the liquid to come out as its only a small hole (bottleneck). if you were to make that hole larger then the liquid would come out faster which applies the same as the charger, your restricting the amount of air it can suck so once it gets to a certain RPM it cannot flow more than .8 bar due to the restriction. Removing this allows it to flow more.

But once you get more air you need to add more fuel, make sense?

PS id stay away from that garage lol

16th December 2005, 20:24

your local performance garage are a bunch of idiots then.

By removing the resistrictor (if there is one) your allowing more air to enter the supercharger and as such will up the boost. Then to stop it runnign lean you will have to adjust the mf2 to match the fuel to the new upped boost

16th December 2005, 20:32

wont be going to the garage again,i like how you compare to a coke bottle

16th December 2005, 20:34

easiest example, I was gonna use milk bottle honest

16th December 2005, 20:47

bloody sparrows and blue tits get into milk bottles though, the boost could be upped without knowing

atl least the coke bottle has a hard plastic top and no birds can mess with the boost...

ill get my coat

16th December 2005, 20:52

ill help you