MAF options
Author
Discussion

8bit

Original Poster:

5,418 posts

178 months

Wednesday 25th September 2019
quotequote all
A friend of mine recently upgraded the supercharger on his Jag XJR, the late 4.2 V8 model. He was advised to purchase an aftermarket MAF from a US firm (who I won't name here), which he did, but it's not working out and they're not responding to his repeated requests for support. The supercharger came with larger injectors and 92mm intake pipework (including the tube with the MAF sensor boss).

Given the whole lot is supposed to work with a 92mm MAF tube am I right in thinking that any MAF from a car which would have had a tube of that size should work, given necessary wiring adaptions? Or, can anyone suggest some other brand of MAF that would work?

stevieturbo

17,967 posts

270 months

Wednesday 25th September 2019
quotequote all
No, it will need to be exactly the correct MAF for the application, and the ecu will need re-tuned to suit this and any other modifications by a competent tuner.

GreenV8S

30,999 posts

307 months

Wednesday 25th September 2019
quotequote all
8bit said:
am I right in thinking
No. The person who is going to calibrate the ECU for you would probably be able to advise on the appropriate sensors and injectors. Don't try to guess.

8bit

Original Poster:

5,418 posts

178 months

Thursday 26th September 2019
quotequote all
Thanks for the replies. I think I phrased my original post a bit clumsily though.

So the supercharger was purchased with larger injectors and the MAF was purchased at the same time as recommended for the type of charger and injectors. It's a programmable MAF (not quite sure how that works exactly) and can be calibrated to work for a given intake tube size. Once all the hardware was installed the car ran poorly so was taken for tuning and the tuner found the MAF readings to be all over the place. The car was taken away and the owner tried to take it up with the manufacturer of the MAF, who have not responded to multiple emails and phone calls. The tuner was not asked for an alternative MAF at the time because the owner of the car thought he'd get the one he had bought sorted but that has not happened.

So yes - we're aware that correct tuning is going to be necessary to get this working but my question was really around getting some other type of sensor that would work. From my admittedly limited understanding of these things a scaling factor can be applied in the mapping, given support from this in the ECU but obviously the MAF needs to be giving consistent readings for this, so I wondered if another MAF, perhaps from the same manufacturer as the one the car was built with (Denso in this case) which was designed to go in a 92mm sensor housing tube would work as a starting point and enable the car to be mapped to work with the new hardware.

Sounds like it'll have to be some other brand of aftermarket part I guess so we'll wait and see what the tuner says.

Sardonicus

19,326 posts

244 months

Thursday 26th September 2019
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Re-scaling of the MAF table should be possible within the ECU's software/operating system to allow an alternative MAF to be used

8bit

Original Poster:

5,418 posts

178 months

Thursday 26th September 2019
quotequote all
Sardonicus said:
Re-scaling of the MAF table should be possible within the ECU's software/operating system to allow an alternative MAF to be used
OK, thanks - could the same thing be used to allow the original MAF to be used in a larger tube?

stevieturbo

17,967 posts

270 months

Thursday 26th September 2019
quotequote all
8bit said:
It's a programmable MAF (not quite sure how that works exactly) and can be calibrated to work for a given intake tube size.
This really does sound like b u l l s h i t

GreenV8S

30,999 posts

307 months

Thursday 26th September 2019
quotequote all
8bit said:
OK, thanks - could the same thing be used to allow the original MAF to be used in a larger tube?
If it has a removable sensor element and you are capable of physically mounting it in the bigger tube, then yes. MAF sensors sometimes include an upstream mesh which allegedly smooths the flow out - if the original MAF sensor needed that you would probably need to retain it in the bigger tube.