Brains Trust Questions re Improving Offroad Performance.

**progen77** · 15-06-2014, 06:05 PM

Hi All,

Long-time lurker, first time poster. I have a 2008 Multivan w/ 4-Motion w/ 150,000Kms on the clock.

So far the car has been very reliable. We did 12,000 Kms last year with a Jayco Discovery on the back, including about 1000Kms on unsealed roads around the Flinders Ranges, Oodnadatta Track and Uluru (without so much as a flat tyre).

This year I’ve had a Bluefin remap done (like driving a new car), as well as the Seikel suspension upgrade (done by Trakka). This has been great for driving on sand. The only downside is that with the suspension raised, the 235/55 wheels look a bit small on the car - so I have the following few questions:-

1) At the moment I’m looking at fitting 245/65r17 A/T type tyres. Are there any brands and models people would recommend? Seriously considering Maxxis again. The current tyres have been very good.

2) Re the loss of torque from driving on oversized tyres, I was thinking about compensating by having the DPF removed by <redacted>, and a Provent added to increase the longevity of the motor (since I gather with the Bluefin tune there is probably a bit more of a load on the DPF and increased blowback of crap into the intake). Does anyone have any experience with these guys? How did the car perform after the mod, and is there a noticeable increase in smoke out the back end? (Please PM me if you are not comfortable discussing in public)

3) The alternative mod I was considering was the Seikel short final drive, since the Multivan gearing sucks a bit for driving on sand and towing. Wolf4x4 quoted $4K to have this done. Has anyone had this mod done to their van? What is the performance like following the upgrade?

4) If you could kindly spare me any lectures on the legality and stick to the technicalities, that would be fantastic

Thanks for listening,

Dan

**Sunny43.5** · 15-06-2014, 06:34 PM

Hope the changes work well . There was a photo recently here on the forum with a guy with those tyre sizes you mentioned but in 17's #Vancation!!!! .

**Transporter** · 16-06-2014, 11:48 AM

From the "technicality point of view", be ready that your drive shafts and diffs will suffer a bit more with larger diameter tyres and reduced gearing when you go for the Seikel short final drive.

Post some pictures and keep us updated on the progress. There is a member who has a lot of experience upgrading his T5 dual cab. He upgraded his diffs plus heaps more mods. Just search a few threads you should be able to find his posts.

I found one of his posts T5 4motion, Just how capable are they as a 4WD
Try contacting him, he is not always in the forum.

**BertieT5** · 16-06-2014, 02:01 PM

1. I have Achllies Desert Hawk A/Ts. They are quite loud road noise wise, but i got them new soooooo cheap I dont mind. Maxxis are pretty good I hear.

2.yes i got a substantial loss with the big tyres. I later did a vieuz (or whatever the brand is) re-map. this brought it back to much like it was before but the boost kicked in earlier. Coz you did it the other way round it is always gunna feel crap.
No idea about DPF delete.

3. Are the Multivan drive ratios diff to the Transporter ratios??? if so maybe a swap to the transporter ratios for 1 and 2 might be better than the 4K option.
Consider the Haldex controller upgrade. I just did mine but dont have anything to report yet since not tested on sand yet, but is said to help lots on sand coz it make it drive 50/50 power when the rears kick in not 80/20. Mine was bought on a group by and i got my mechanic to drop it in in the last service.

4. :-p

**progen77** · 17-06-2014, 11:54 AM

Originally Posted by Transporter

There is a member who has a lot of experience upgrading his T5 dual cab. He upgraded his diffs plus heaps more mods. Just search a few threads you should be able to find his posts.

The retrofit rear-diff mod sounded pretty impressive, albeit damned difficult and well outside my skill set. Are there any places that would be likely to be able to do this sort of work?

**progen77** · 17-06-2014, 11:58 AM

Originally Posted by BertieT5

Consider the Haldex controller upgrade. I just did mine but dont have anything to report yet since not tested on sand yet, but is said to help lots on sand coz it make it drive 50/50 power when the rears kick in not 80/20. Mine was bought on a group by and i got my mechanic to drop it in in the last service.
4. :-p

Did you get the controller with manual select or the automatic one? Do you notice any difference in driving on the road? Very interested to hear your reports...

**Transporter** · 17-06-2014, 01:31 PM

Originally Posted by progen77

The retrofit rear-diff mod sounded pretty impressive, albeit damned difficult and well outside my skill set. Are there any places that would be likely to be able to do this sort of work?

A good mechanical workshop should be able to handle that kind of job. You can also ask (if you already haven't) at the 4x4 shops/workshops if they have anything for the T5s

**BertieT5** · 27-06-2014, 10:07 AM

Originally Posted by progen77

Did you get the controller with manual select or the automatic one? Do you notice any difference in driving on the road? Very interested to hear your reports...

Apparently the hand piece controller that allows u to swap maps won't work on the T5, so just buy the diff controller by its self. I have info somewhere stating the t5 diff is missing the fruit the golf gti ones has so the hand piece for swapping maps won't work but you can never be sure. It puts the standard map to sport, the most aggressive is race, but prolly not the best for part life long term.
Talk to the guys from HPA they do a great deal even from the USA!

**Big Bug** · 05-07-2014, 03:12 PM

Dan
Wolf4x4 quoted $4K to have this done. So what were they actually quoting for $4k? I'm interested because I talked to Trakka at the Brisbane Camping and Caravan Show and they quoted me around $12K for the Seikel Short final drive ratio T5 4Motion. That is all up fitted. When I talked to Wolf earlier in the year they said they couldn't sell Seikel stuff for the T5 as Trakka had that and they had Amarok Seikel gear..

Thanks

Bruce

**progen77** · 05-07-2014, 04:10 PM

Originally Posted by Big Bug

Dan
Wolf4x4 quoted $4K to have this done. So what were they actually quoting for $4k? I'm interested because I talked to Trakka at the Brisbane Camping and Caravan Show and they quoted me around $12K for the Seikel Short final drive ratio T5 4Motion. That is all up fitted. When I talked to Wolf earlier in the year they said they couldn't sell Seikel stuff for the T5 as Trakka had that and they had Amarok Seikel gear..

Thanks

Bruce

Hey Bruce, just checked the e-mail trail from Wolf4x4. I was e-mailing Ashley Gibbons. Price quoted was $3995 for the kit, including fitting by Volksmuller in Annangrove, Syd. Interesting that you mentioned contacting Trakka, I did the same and they flat out refused to do the job for any amount of money because the car was more than 12 months old (apparently something to do with their agreement with VW, rather than any technical reason).

I wonder if we could get a group order going...