| View previous topic :: View next topic |
| Author |
Message |
markd89
Initiate Jedi
Joined: 24 Aug 2008
Posts: 29
|
 Posted: Sat Oct 31, 2009 6:28 am Post subject: Gearing for TDI in bay window |
 |
|
Hi All,
I'm planning a TDI conversion for a 78 bay window bus. I will get a re-geared transmission. I'm curious for anyone who has done this conversion what a reasonable RPM I should go for for highway cruising. i.e. 65 MPH -- is 2000 RPM enough, or would I be down-shifting everytime I come to a hill?
I appreciate any suggestions.
Thanks,
Mark |
|
| Back to top |
|
 |
sven
Jedi Guardian
Joined: 27 Dec 2006
Posts: 814
|
| Posted: Sat Oct 31, 2009 12:17 pm Post subject: |
|
|
What TDI is it?
I would say 2000 is too low, the bus has more drag than a normal car in highway speed and is a little bit heavier as well. After a quick googling I got a value about 2000 RPM @ 60 mph for a -96 Passat.
If we compare with brand new effecient diesels and Jetta/Golf models. I have Touran -05 with the first 6-gear DSG box (it has now 7!) and it revs around 2200 at 65 mph (if I remember correctly). The new Golf is also at 2000 @ 60.
If I were you I would figure out the RPM for the original car at 65 mph as the gearboxes usually are configured to give the optimum RPM at an estimated highway speed. You may go a little bit lower on RPM then, but as I wrote in the beginning the drag of the bus is higher.
I would guess 2500 is better in that case. On the other hand, you haven't told us what engine this is about. If you're going to put a 3 litre Cummins diesel in the poor little thing we have another story. And you need another gearbox.  |
|
| Back to top |
|
|
markd89
Initiate Jedi
Joined: 24 Aug 2008
Posts: 29
|
| Posted: Sat Oct 31, 2009 2:31 pm Post subject: |
|
|
Hi Sven,
I'm looking at using an AHU. I may do some power upgrades, but I want to plan for stock power.
Thanks,
Mark |
|
| Back to top |
|
|
sven
Jedi Guardian
Joined: 27 Dec 2006
Posts: 814
|
| Posted: Sat Oct 31, 2009 4:55 pm Post subject: |
|
|
Original 90 hp's. 2000 RPM @ 65 mph is too low. As I said, try to find out what the donor car has. Jetta -96 was 2000 RPM @ 60, that would be closer to a better value I believe.
In the end it all depends how much you want to squeeze out from it. 
 |
|
| Back to top |
|
|
markd89
Initiate Jedi
Joined: 24 Aug 2008
Posts: 29
|
| Posted: Sat Oct 31, 2009 10:54 pm Post subject: |
|
|
| sven wrote: | Original 90 hp's. 2000 RPM @ 65 mph is too low. As I said, try to find out what the donor car has. Jetta -96 was 2000 RPM @ 60, that would be closer to a better value I believe.
In the end it all depends how much you want to squeeze out from it.
|
Very nice dyno. I know it's a slippery slope ;-)
The engine is from a 97 Passat.
I spoke with the venerable Giles in Canada about converting the pump to mTDI and doing his tuning magic on it. He said I could get 110 hp just from that and 130 hp with bigger injectors and more boost. So I guess I'll be looking at 110 minimum HP. Giles suggested I aim for 2500 rpm at highway speed. My goals are more MPG as well as more peformance so I don't want to be turning more RPMs than I have to.
I'm thinking about re-gearing all 4 gears so I suppose I could gear for 2200 @ 60 or something in 4th gear and if there's not enough power for a big hill, drop down to 3rd gear which would still allow for 70 mph. Maybe?
Mark |
|
| Back to top |
|
|
13 window deluxe
Jedi Guardian
Joined: 22 Dec 2006
Posts: 861
Location: chesterfield derbyshire
|
| Posted: Sun Nov 01, 2009 9:09 pm Post subject: |
|
|
hi with stock gearing on a ahu tdi golf 3000 rpm in 5th is 80mph, i built a ahu tdi 1980 bay (Check out my old posts) i used a 6 rib 091 2lts cp code gearbox it would cruise at 70mph all day long and you never had to shift down even with the biggest hill and it would pull a house down
_________________
1964 rat 13 window deluxe 1Z tdi,
1975 rhd twin slider tintop (TBA)
1991 golf 2 gti with tweaked AHU tdi,
previous tdi swaps: gone but not forgotten
1979 rhd twin slider tintop bay ahu 1.9tdi
1990 T25 1Z 1.9tdi
1993 suzuki samurai with 1Z 1.9tdi |
|
| Back to top |
|
|
13 window deluxe
Jedi Guardian
Joined: 22 Dec 2006
Posts: 861
Location: chesterfield derbyshire
|
| Posted: Sun Nov 01, 2009 9:12 pm Post subject: |
|
|
i would stick to a original pump or a afn pum and larger injectors but a word of warning your gearbox will not like the increase in torque
_________________
1964 rat 13 window deluxe 1Z tdi,
1975 rhd twin slider tintop (TBA)
1991 golf 2 gti with tweaked AHU tdi,
previous tdi swaps: gone but not forgotten
1979 rhd twin slider tintop bay ahu 1.9tdi
1990 T25 1Z 1.9tdi
1993 suzuki samurai with 1Z 1.9tdi |
|
| Back to top |
|
|
markd89
Initiate Jedi
Joined: 24 Aug 2008
Posts: 29
|
| Posted: Sun Nov 01, 2009 9:25 pm Post subject: |
|
|
| 13 window deluxe wrote: | | hi with stock gearing on a ahu tdi golf 3000 rpm in 5th is 80mph, i built a ahu tdi 1980 bay (Check out my old posts) i used a 6 rib 091 2lts cp code gearbox it would cruise at 70mph all day long and you never had to shift down even with the biggest hill and it would pull a house down |
Thanks for taking the time to write. You're using a stock geared 091, right? I figured with stock gearing the bus would have tons of power more than needed and probably have MPG suffer. Thats why I wanted to regear to drop the RPMs and improve the MPG.
What mileage are you getting?
| 13 window deluxe wrote: | | i would stick to a original pump or a afn pum and larger injectors but a word of warning your gearbox will not like the increase in torque |
My intention to move to an mtdi pump was more to simplify wiring than gain power (although more power is nice). If I thought I would figure out the wiring in a day or something, I'd probably leave it electronic. Is my concern misplaced?
What do you think the practical torque limit is of the stock 091?
Thanks again,
Mark
(PS I will go look for your posts from your conversion. I appreciate all the help) |
|
| Back to top |
|
|
13 window deluxe
Jedi Guardian
Joined: 22 Dec 2006
Posts: 861
Location: chesterfield derbyshire
|
| Posted: Sun Nov 01, 2009 10:02 pm Post subject: |
|
|
the wiring isnt that bad but you need the vw wiring diagram for the engine most are us diagrams so dont include the immo wiring but this is easyish.
its hard to say about the torque limit but dont go to mad you will be suprised how well a stock ahu goes in bay.
_________________
1964 rat 13 window deluxe 1Z tdi,
1975 rhd twin slider tintop (TBA)
1991 golf 2 gti with tweaked AHU tdi,
previous tdi swaps: gone but not forgotten
1979 rhd twin slider tintop bay ahu 1.9tdi
1990 T25 1Z 1.9tdi
1993 suzuki samurai with 1Z 1.9tdi |
|
| Back to top |
|
|
sven
Jedi Guardian
Joined: 27 Dec 2006
Posts: 814
|
| Posted: Mon Nov 02, 2009 9:56 am Post subject: |
|
|
I regret I didn't go the diesel route with my conversion. I don't get it, all my other cars are diesels...
Is it too late to change mind? |
|
| Back to top |
|
|
markd89
Initiate Jedi
Joined: 24 Aug 2008
Posts: 29
|
| Posted: Mon Nov 02, 2009 10:05 pm Post subject: |
|
|
| 13 window deluxe wrote: | the wiring isnt that bad but you need the vw wiring diagram for the engine most are us diagrams so dont include the immo wiring but this is easyish.
its hard to say about the torque limit but dont go to mad you will be suprised how well a stock ahu goes in bay. |
I'm in the US, so the wiring should be without the immobolizer. As well as the ECU, wiring harness. Do I need the cluster or any other parts?
Is the AFN pump a performance upgrade?
Thanks,
Mark |
|
| Back to top |
|
|
13 window deluxe
Jedi Guardian
Joined: 22 Dec 2006
Posts: 861
Location: chesterfield derbyshire
|
| Posted: Tue Nov 03, 2009 5:57 pm Post subject: |
|
|
apart from the bits in the engine bay theres just the loom and ecu and the power control / glow relays out of the fusebox inside and the throtle position sensor of the pedal box
_________________
1964 rat 13 window deluxe 1Z tdi,
1975 rhd twin slider tintop (TBA)
1991 golf 2 gti with tweaked AHU tdi,
previous tdi swaps: gone but not forgotten
1979 rhd twin slider tintop bay ahu 1.9tdi
1990 T25 1Z 1.9tdi
1993 suzuki samurai with 1Z 1.9tdi |
|
| Back to top |
|
|
|
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
