calibra injectors and vr6 maf before map?

[jamie16v]

just bought some yellow LET injectors along with a VR6 maf, the car is off the road at the moment, would it be ok to fit injectors and maf before remap and mot or would you advise fitting them on the day of the remap?. i need to get the car taxed and mot`d before i consider driving up for the remap so that kind of explains my issue. would the car run fine and give reasonable emmisions on current map with said injectors and maf?.

[Chris#101]

R-tech did you get my message I sent you!? As theres no 'SENT BOX' im unsure whether it got sent or not!?

cheers

[Chris.]

Id just fit them when you get there mate.  not the hardest of things to swap over!

[jamie16v]

Id just fit them when you get there mate.  not the hardest of things to swap over!

True, but its a long drive to leicester. less time pissing about under the bonnet when i get there, the the earlier setting up on the rollers, the sooner i get home..
if it`s not going to be o.k then fair enough..

[MaXXeH]

i think ur find it will run ruff mate,  overfueling ect.  Just change them when your there 20min job   ..... or install them and run with the maf d/c it may be ok.

[jamie16v]

 ..... or install them and run with the maf d/c it may be ok.

if anything i would say that would make it run rich as the injectors are not suited for the limp mode map?. being that the limp mode calculation would then be taken from the throttle position sensor if the maf was found to be disconnected(as the ecu is programmed to open the injectors at a predermined % duty cycle for the amount the throttle is opened).what i am saying is, wouldnt the % upscale of maf vs. %upscale of injectors  be needed in order for the fueling to level out?. i know it wouldnt be spot on but i close?..

[MaXXeH]

when i installed larger injecters in my car it run far better with the maf d/c.   Your have no boost so it wont create u many problems... reads from lumbar sensor also..

I think if you run it with the maf connected, it would not know the injecters are larger so it would over fuel all over the place under boost. Then put it self into limp mode...

just my thought mate 

[jamie16v]

when i installed larger injecters in my car it run far better with the maf d/c.   

when you fitted the larger injectors did you fit a larger maf too?. which injectors did you fit and what maf was fitted at the time?.

[jamie16v]

i think this answers my original question  and confirms my theory!

so bigger injectors always means bigger MAF?

AGU / cable 1.8T / motronic 5 ecu / m3.8.* ecu

The AGU uses a narrow band ecu which every thing in the mapping ie primary fuel, timing and load is ALL based around the reading from the maf.  The injection on-time is made up from maf reading, rpm and engine load.  If you fit bigger injectors then the engine will run too rich and the ecu can only trim a small amount of the extra fuel by using the narrow band 02 readings.
 If you change the MAF housing % size to the same % increase as the injectors then the ratio for injection ms and air drawn will be about spot on or within an ideal range for the ecu to trim by around 5-10%, then when is comes to mapping all we have to do is rescale the load axis on the ignition maps and fine tune the injection ms map, which can take a round a whole day to dial in from scratch. There is a way of just adding bigger injectors to the ecu but this mean changing the main global konstant ratio map, but doing this off sets all the map load axis and can take days of logging to rescale and get correct and will cost £100s.

AUM ARZ AUM ME7.5 ecu

These ecus allow just for the injectors to be fitted and just one map to be changed. The map KRKTE which means constant factor (K) for air flow (RK) to injection time (TE) just by changing this one map in the correct ratio to the injector size will allow the fuel to be near enough 100% bang on,  The only other time the KRKTE map should be changed is when running a 4bar fuel reg, I would say 99.9% of all tuner who are mapping car with 4bar fuel regs are not doing changing this map which lead to high fuel trims and loss of power due to too much fuel lower down in the rpm range....


So dont just go and fit a 4bar reg... it wont work right unless its been added in the mapping (check with your tuner that the KRKTE is set for a 4 bar reg. 
 A lot of the Seat 1.8t boys are just wacking 4bars reg on there car and making less power.. .  Going for 600cc+ injectors then a few more map need to be chnaged to get it bang on.

In theory.. a cheat just by adding 30% bigger injectors and MAF will give 30% more load request which could work out to be around to 30+bhp with just stock mapping.  It wont kick like a remap and the N75% mapping wont change enough and the load map in the ecu is still on a linear scale.

I hope this helps..   sorry to bore you all

[RTechUK]

You can scale to air flow to fuel flow increase % so fit vr6 mf and c20let yellow you should be fine fuel trims around -8% . But if your car is mapped and the  16x16 part load fuel map has been adjusted then you can get a fuel dump in the midrange and on fuel enrichment and trims -20%

IMO best get everything done and leave fitfing maf and injectors until the day of custom remapping.  As long as you mock the MAF up to the TIP/ air box prior then is only a 15 min job to fit them on the day.

Nick