I have had a good experience with the DBX85, have run it for a year or so and 10k miles with no problems.

It is really easy to adjust and a very nice feature is you can program 8 curves and pick them with the switch on the meter. I found this really handy for fine tuning, to program a series of similar curves and be able to test them all in one drive session.

If you do go with the DBX and are interested, I can send you a starting calibration curve. It won't be quite right for your car as mine is an AJ34 but it should be in the ballpark and saves having to start from scratch.

Avos has a copy of it as well.

 

OMG I can believe the amount of info you guys are sharing thanks... I have to admit a small mistake on my part, it has all become a bit of a blur. Below are the actual readings, quite different from above. I hope this make more sense to you now...

Direct quote from an email I found....

The 4.2 injectors with the increased flow and pressure that we run is capable of providing a good air flow ratio mixture. When you are driving a car hard i.e. full throttle, you need a fuel to air ratio of 12 to 1 to 11 to 1, you are running at 14 to 1 with the big air flow meter. This is too lean. Andre is adapting another air flow meter and with upping the injectors we should be Ok.

You guys have so much knowledge I will be putting all your suggestion forward before changing the ECU...

 

HI, I have 4.2 injectors and 2 x 90psi fuel pumps.

 

Hi, Tom advised that He was going to add Normans setup to my car as he knew that worked.. no idea what Normans setup is but will ask about your DBX85 thanks

 

4.2 injectors at 55 psi, is more than enough not to peg the MAF on your setup if you would have a 90mm TB (and to right filter as suggested). The stock pumps will not manage this though, you need at least uprated pumps, or the KB boost a Pump. What setup do you have now?

I have put now a DBX97b on my car as I am preparing for a big jump in power again. This one allows more airflow, but is basically the same unit in how you program it as the DBX85 (please note, this MAF is not needed for 600 bhp, it would be overkill). I have also now 530cc injectors, for which I have of course adjusted the DBX97B to, and this works very well (8K miles iirc, or even more now).

Anyhow, I can’t see a reason why the 90mm TB on your car wouldn’t work, especially now that you are already using a higher flow injector with the tunable DBX85 MAF. It may take some tweaking, and if you come to Belgium I am more than happy to support you.

 

Had a look at

Mustang Performance Parts by Anderson Ford Motorsports

Found the 85mm and also a 97mm. As I've gone to the expense of a 90mm TB any ideas what would happen if i got the 97mm version fitted... sounds like it should work based on what Avos has typed..

Do i need the 530cc injectors?

I know i had up-rated fuel pumps fitted, up to 90psi. No idea about the KB booster Pump!

Thanks for the offer of a trip to Belgium.. lets see.

 

You certainly do NOT need the DBX97 or the 530cc injectors, unless you want to shoot for 700 bhp or more as I am working on right now. My setup with the 90mm TB, 4.2 injectors (at 63 psi) and 3.5"maf gave me already a comfortable 600 bhp+.

Stay focused now 1st on getting the 90mm TB to work with the setup you have now (after the pumps are verified) with the dbx85.

 

Hi if I fit the dbx85 I will be limiting the air flow and the whole point of me going to the expense of the 90mm TB was so I got as much power out of the car as possible with resources to hand.
What would be the issue if I fitted the 97.
What's the difference between the 97 and 97b and do they even sell the 97 now?

 

The amount of vacuum the SC would create thru the intake is determining the power loss. So a 20% large intake does not mean a 20% increase in power as an example, it all depends on how much vacuum you have, and from that you could guess the power difference. On my original setup (600 bhp+ and 90mm TB), there would only be a tiny difference between the DBX85 and DBX97 based on the vacuum measurements, possibly 5 hp or so, meaningless on these sort of power levels. The difference in flow between the DBX85 and the 90mm TB would also be very small, as the butterfly would create more drag then the sensors of this MAF, so it’s not a straight diameter comparison you can do here.

It mainly depends on how far you want to take the hp levels, i.e. how much power/pressure you want to run at. Based on that I can make some recommendations. If you stay with the stock pulley size (3”) a 90mm TB and DBX85with suggested filter would give you about 20 psi which would be the max I would recommend for street use (98 ron or higher fuel) .

If you go for smaller pulleys (so upping the boost and thus increasing the airflow), then pending on what level you select, you at least need more protection, so higher ron fuel or water/meth, and adjustments to the fueling system (though you have some room now already).

The disadvantage of the larger MAF (DBX97b) is that it is less accurate at low flow levels, I took me some good time to tune that part when installing the bigger injectors, but it does work. It is a very big unit, it barely fits in my bumper and I am not sure if it would even fit a pre 2004 bumper. It is also difficult to get at when you want to do tuning or want to switch one of the 8 settings. For now I have a cable directly attached in case I want to play with it.

The 97B version has a large bellmounth, which aids the airflow again.

You’re free to choose what you want, I don’t dictate anything, just give my opinion.

 

Hi, Avos

I am after a bit of clarification after your last comment about the HP difference between 85 and 90mm MAF, you say only 5hp?
Below is a snip it from your page;

https://www.jaguarforums.com/forum/p...59/#post243827

Kits available:
Supercharged 4.0 (AJ26) XKR and XJR's (with stock bored out 82mm TB)
Supercharged 4.0 (AJ27) XKR and XJR's (versions with Stage II 90mm TB)
Supercharged 4.2 XKRs up to 2006 (steel bodied versions, Stage II 90mm TB)
I think I have a combination of all 3,

AJ26, 4.2L with a 90mm TB…..
I ordered a Stage I Kit from you but with a 90mm intake – I think..
- 2.6LH Large Bore High Compression Twin-Screw
- Extra power range about 120 HP to 180 HP.

The Stage II kit with a 90mm TB gives between 140 HP to 220 HP.
So this where I get confused!

If the difference between an 80mm TB and a 90mm TB is 20-40BHP, why would I only get 5 extra HP moving from an 80mm to 85mm air intake? The two must be linked somehow. Surly if you fitted a 90mm TB with an 80mm MAF the 80mm would reduce the max possible BHP due to air flow. And if as you say there is only 5BHP between 80 and 85 how can there be 20-40BHP between 80 and 90?

I’m not trying to be difficult but I don’t understand and maybe I never will!! Can you explain?

I'm always happy to listen to peoples opinions and then make my own mistakes ..

 

I compared my 90mm TB with the 2 different MAFS (so all else the same), so the DBX85 and DBX97b, and that would at most give about 5 hp with the 3”pulley.

When you increase the airflow (so change pulley), then the difference will get bigger obviously.


So getting back to your example:

Results:________80mm_______90mm______Flow Rate % increase
L/s____________40.86_______51.71_________21%

If your engine is only sucking in 40.86 ltr/s. Going to a 90mm makes no difference at all, the engine will not need more, so the added capacity is overkill.

If your engine is sucking in 51.71 ltr/s and you would use the 80mm setup, it’s obvious at a disadvantage, as there is more restriction in this size pipe. This restriction is going to cost power, as you will create some vacuum (engine needs more then you can get in via the pipe). Now you are not limited to 40.86 ltr/s by the 80mm pipe, as that was a measurement based on a certain restriction (or without, pending on how it was measured). So instead of the 51.71 ltr/s you would probably get more like 48 ltr/s or so with the 80mm setup (figures are just to illustrate).

That is why I asked how much hp (air flow) you want, as that determines how big everything ideally should be.

Hope this helps.

 

Hi. I think I am starting to get this. 3" pulley only needs x amount of air. And an 80mm MAF system is sufficent. Correct?
So if the pulley is changed to y then the SC will pull more air and require a larger bore MAFS correct?
On your spec I could see a 3" pully with the 80mm setup but not a smaller pulley on the 90mm setup. What size pulley should I have fitted to take maximum advantage of the 90mm TB And would it be different if I fitted a 85 vs 97b air flow meter?

Just seen this.

http://www.andersonfordmotorsport.com/pro-m-mass-air-flow-meter-92mm-80lb-injectors-fits-89-93-5-0l-mustang/

This is about the right size so not over kill like the 97 and not undersized like the 85. Thoughts?

 

I am not aware if a 80mm MAF, the stock one is about 75m (little less iirc), and the DBX85 is 85mm.

The Stage I (for AJ27 engines, which I discontinue due to no interest) is making use of the stock MAF and a 75mm TB.
As you can see in my sig, I am going to go for 700 bhp next, and I will still use the 90mm TB, where ideally 95 or 100 would be better. The 90mm may not be the most efficient (where it is for 600 bhp) obviously, but the costs to change that again would be too high for low gain.

The ProM one can't be custom tuned, major disadvantage, and they only have a tune for the AJ27 and AJ34 engines.

You may call the 85mm MAF undersized, but remember I pulled 630 bhp with it on my 90mm TB.

 

Which pumps do you have?

 

I've mailed Tom as I don't know exact model and don't have access to the invoice due to being on holiday and out of the country, hence time to update things on this forum...will advise when I know. But from memory Tom said they would give up to 90psi...help?

 

Hi I feel like we are going round and round in circles and I'm just not getting it..

Maybe start with something more basic than basic for me....If you don't mind answering the couple of questions below this may help me..

A SC with a 3" pulley only needs X amount of air and an 80mm MAF system is sufficient. Correct?

So if the pulley is changed to Y then the SC will pull more air and require a larger bore MAFS correct?

On your spec I could see a 3" pulley with the 80mm setup but not a smaller pulley on the 90mm setup. What size pulley should I have fitted to take maximum advantage of the 90mm TB?

I now have in my mind 3 things that need to happen in order to get the highest BHP.

The SC must be wound really quickly by the engine, hence different size pulley's. The smaller the pulley the faster the SC, the faster the SC the more air it needs, hence larger MAFS 85-90mm. The more air the SC takes the more fuel required to give the correct fuel to air ratio, hence higher PSI fuel pumps.
The air flow meter helps the ECU know how much fuel to add at different speeds. Is this about right?

If yes then why when I have a 90mm TB an and 80mm MAFS do i not get any where near your 600BHP. if 5mm bigger MAFS will only give 5 BHP should I even bother changing it, or do you think the problem somewhere else? Or will having the DBX85 fitted give a very different set of results due to its programming?

Once again thanks for your input on this topic.

 

Not sure if Tom told me or not, 90 psi as such doesn't mean a thing, how much flow at that pressure is what counts, at least at 80 to 85 psi.
So I need to know which pumps to be sure.

Am enjoying a holiday as well at the Côte d'Azur, but unfortunately without my car...

 

Sorry can't help you more on the flow part, I would have to repeat myself again.

You might want to browse the kennebell website, and study the hp figures they show for different setups.

You are at least mixing up efficiency with maximum possible flow. Think in efficiency only, maybe that helps?

 

Hi. Tom has just confirmed
2 x Bosch 0580254040.

 

These are perfect, I use them myself as well.