Well I asked Cambo and Moscow Leaper, bad news is that the chip data in the mopar TB can't be accessed. Good news is that the PCM can pe calibrated to take into account the larger TB. Right now I am very likely to buy the sechtor 83mm TB on Jazzyjags' former XJR, and have it sent to maxbore, to see how large he can go. I don't think 90mm is in the cards, but 86-87 is an achievable goal.

Andre, do you have some data of the hp delta between different TBs on your setup? Or did you go 90mm from the start?

 

Maxbore don't handle larger TB's for at least a couple of years, he told me that's why he stopped doing Jag ones. Maybe he's bought a larger lathe since.
As to boring out the Sechtor one, I understand it's pretty close to the limit in places.
EDIT:- Try emailing Cristian, who organised it, for his opinion on the wall tolerances.

 

I went in steps, difficult to say, for your setup I could make an estimate if you know the vacuum at full throttle (so close to 6000 rpm), ideally it should be 0, any vacuum is costing actual hp.
The latter is even the case for the stock 75 mm intake/TB, so the 83mm is already a very good improvement, though when you again spin up the supercharger (or have a KB), then 83 is becoming restrictive again leaving hp on the table.
Here the area differences, going from 83 to 90 provides already about 19% more area for flow, and to 88 already 13%.
(key remains what vacuum you pulled to determine the gains)

 

I bought jazzyjags XJR as a basketcase with the Sechtor throttle body... It also has the ProM MAF sensor... If somebody has this set up I would love to talk to you! I have some pictures of how the wiring should go but it's somewhat inconclusive... If somebody thinks they can get me through it I'll be glad to pay a consulting fee and maybe do a facetime session...

 

Hi,
The car is finally with tuner and fault code coming up with Throttle Body putting into limp mode. I installed the Sechtor 83mm TB as discussed in this thread. Any help would be much appreciated!

 

On what your car?
I can tell you we have done a few 06+ cars were throttle opening needed to be adjusted on ECU, no check engine lights no limp modes of any kind . This was on stock but Ported tb including the larger butterfly....

 

Hi,
It's a 2003 X100 XKR so has the AJ34S 4.2 engine. We transferred the TPS and actuator from original TB over so been advised that the butterfly opening will have to be adjusted on the valve to control the air opening to within the ECU permitted range of air flow. Any info would be much appreciated!

 

Sorry iv only done this on 06+ cars with the newer ECU

 

The 03-06 cars are called "orphan ecu/tcu" for a reason...

06+ are easy to work with. My 2003 build 4.2 is currently undergoing mapping for 850cc injectors, 4" MAF & ported stock TB. I have Moscow Leaper & Cambo to help me, I am using the Russian Scanmatik interface (doubt you can buy it now I got mine just before the war started). You then use a Russian made software that has a module for our 2003-2006 to write the ECU. But again, you need the Russian interface.

This however is custom tuning(i.e. not cheap), and progress is quite slow, but I am soo happy finaly somebody could crack the Denso 32bit ECU!

I believe the easiest route would be to revert back to the stock TB, perhaps maxbored. Guaranteed that the stock setup will work. I had my maxbore 81mm stock unit without tuning, and has worked flawlessly.

I would be very interested in buying the 83mm Sechtor from you, please let me know if interested.

 

Maxbore states they don't do Jaguar TB anymore

 

When I was in contact with him, he said he will do it but for an extra charge as its very time consuming

 

When was this, please ? When I spoke to him he said that the replacement lathe he bought wouldn't accommodate the large Jag TB's.

 

23rd December 2021

 

That's good to hear & worth me contacting him again. My last contact was June 2020.

 

I will have to check as well...I'm thinking of selling my 83 Sechtor...

 

Actually the last time I spoke to him this summer, to ask whether he would port the Sechtor (yeah, I am greedy!), this is what he said:

Hello Matt.

Sorry, I don't work with aftermarket TBs.
They do not follow standard design and manufacturing, so they are a complete pain to disassemble and reassemble.
I work exclusively with Original equipment throttle bodies.

Thank you
George
Maxbore.com throttle body boring service and repair

So he confirms he ports our OEM TBs. If you look on his site, you can see the 2003-2005 Jag TB.
What you may have heard about him not doing it anymore may refer to the more complicated process of boring to 81mm, which envolves epoxy, and the risk that the TB cracks in the process. Also About 5 years ago I remember him saying that he would only do the simple boring to 78.5mm, without the epoxy.

Still, from stock to 78.5mm is a blessing to the engine. However, keeping in mind the Eaton is already close to maxed out, going up from there would adhere to the law of diminishing returns. Now why I am smooth-talking myself into buying a sechtor is that the 3.0 Kenne Bell supercharger is no longer the bottleneck, nor is the 102mm MAF, nor the 90mm piping, it's the TB.

Mine is the epoxied 81mm, to which I have overground the shaft, so that one of the screws which holds the blade doesn't fasten it fully - thus It vibrates at very low idle. To me, any additional mm would mean huge benefits.

If/after I get a Sechtor, I am willing to let go of my current 81mm TB - the case is intact, but it would require either a shaft replacement (the stock one), or some jb weld to keep the the throttle blade in place.

Best thing would be to ask George directly. 100% he can go to 78.5mm, and if you really want to go 81, ask him if he'll reconsider. But even if you only go 78mm, the most benefits are to be had at the beginning.

Yes, a Sechtor would be a great Christmas gift to myself, so please PM if you're willing to let go of the one you have

 

I thought some of those following this thread may be interested that I have recently been able to get a hold of a 83mm Maxbore throttle body, and am quite sure that I would be able to replicate the process of boring a standard throttle body and rebuilding with a new butterfly

I understand that there are quite a few superceded part numbers for the TBs on the STR/XJR and that some of these have varying wall thicknesses. We will therefore bore as far as we safely can, within the limits of the factory casting.
​​​​​​
If anyone is interested in a bored TB for their XKR, STR or XJR, please PM me as costs can be reduced if the TBs are prepared in batch.

 

These 83 mm throttle bodies are nothing but headaches... I bought my XJR from jazzy jags and he never got it to run quite right either it was always some issue with it... fast forward to when I bought the car, I gave up after about 3 days of dicking around with it... From a performance standpoint the gains are absolutely not worth it take it from someone who knows!

 

I think you're referring to the Sechtor 83mm TB which was a completely new unit - you are correct in that many of those who purchased it experienced issues.

I'm however referring to a stock Jaguar TB which is simply bored and rebuilt with a new butterfly. This will work just like the standard TB (because it is in essence), and many have used and continue to use Maxbore TBs without any issues. Also on twin screw cars like mine, the ported TB is absolutely worth it as the TB becomes a bottleneck when higher vacuum is pulled.

 

Yes, you're right. That does make sense! I would say most cars would not see much of a performance gain unless it was pretty heavily modified like yours