2 questions about a diesel upgrade

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pengyou
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2 questions about a diesel upgrade

Post by pengyou »

1. Has anyone ever done a detailed measurement/sketch of the engine compartment of the astro to be used to determine whether a 4bt or other diesel would fit? What would be ideal is if someone had a cad drawing of the engine compartment. Measurements would be OK though :)

2. Someone has mentioned that the auto tranny for the V8 engine will fit on the v6 engine and, with an adapter, will fit a diesel, even with the extra torque. My question - would the gear ration on the V8 tranny be appropriate for a diesel engine? My guess is, no.
New owner of a 1996 Astro named "Plain Jane" - stock right now - with 200,000 miles on it and running like a champ

ihatemybike
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Re: 2 questions about a diesel upgrade

Post by ihatemybike »

It's not the tranny ratios that really come into play it's the rear diff. Since a diesel turns slower with greater torque it's not uncommon to find rear diffs in the low 3s.
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Someone
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Re: 2 questions about a diesel upgrade

Post by Someone »

I would do the install, take it for a drive and then regear the rear end as needed, as long as you can cruise at a good RPM on the highway you should be fine. my dually has 4.10's and only does about 75Mph... I could lower the ratio to get more top end, but it is not really needed in a big truck
'98 Mercedes E300 Turbo Diesel
'89 4Runner SAS'ed, 38.5SX's, Mercedes OM617 Turbo Diesel
'98 Suburban K2500, Cummins 24Valve, 5spd 4x4
'03 VW Jetta TDI
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GEJ
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Re: 2 questions about a diesel upgrade

Post by GEJ »

pengyou wrote:1. Has anyone ever done a detailed measurement/sketch of the engine compartment of the astro to be used to determine whether a 4bt or other diesel would fit? What would be ideal is if someone had a cad drawing of the engine compartment. Measurements would be OK though :)

2. Someone has mentioned that the auto tranny for the V8 engine will fit on the v6 engine and, with an adapter, will fit a diesel, even with the extra torque. My question - would the gear ration on the V8 tranny be appropriate for a diesel engine? My guess is, no.

Or your could spend and get:

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original_balzer
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Re: 2 questions about a diesel upgrade

Post by original_balzer »

You can get a cummins 4BT out of a bread van they used a GM TH-400 transmision. No adapter needed, they bolt right up to GM transmissions.

The transmission has to be diesel specific as the diesel has low opperatring RPMs. That means the gas transmission would not shift correctly for the diesel engine. Its not a serious issue as Im sure a transmission shop would be able to set up the transmission correctly.

A 4BT should fit anywhere a 350 V8 would fit lenth and width wise. The hight is what you will need to know as the cummins are rather tall engines.

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pengyou
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Re: 2 questions about a diesel upgrade

Post by pengyou »

Yes, it is the height that I need to be concerned about. Weight is also going to be an issue as well. The 4bta is heavier even than the v8 350 - I think by more than 100 pounds, and then there is the added weight of a heavy duty radiator, second battery, etc.

The overdrive would be awesome but at about $ 2,800 I think I will either buy a new tranny or a new rear end and take the $ 1,500 I save and buy pop tarts :)
New owner of a 1996 Astro named "Plain Jane" - stock right now - with 200,000 miles on it and running like a champ

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Re: 2 questions about a diesel upgrade

Post by Someone »

If you want to use your transmission you will need a lower stall torque converter, some sort of electronic shift controller would be a nice option aswell
'98 Mercedes E300 Turbo Diesel
'89 4Runner SAS'ed, 38.5SX's, Mercedes OM617 Turbo Diesel
'98 Suburban K2500, Cummins 24Valve, 5spd 4x4
'03 VW Jetta TDI
'78 Vette 350 4spd

www.vehiclefleetsolutions.ca

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