Garrett m24 AR .80/.63 turbo on ahu?

Ok, so I'm in the long process of building an ahu for my caddy, and I need to figure out what turbo I want to use. The original turbo was used on a different vehicle, and I'm thinking I probably want to go with something that flows better for better efficiency. (The stock kkk turbo is SMALL!) maybe just seems so since I work on a lot of big trucks...
So, I have three Garrett m24 turbos that are for a Nissan 300zx twin turbo. They have no shaft play, and I think (from what info I could find) they are maybe ball bearing?
But, they are big... The intake is .80AR and exhaust .63.
Is that going to be too big for a 1.9 tdi? Other option is I have a Mitsubishi tc05-10 turbo from a Mitsubishi 4d55t out of a Mitsubishi mighty max diesel pickup. I used it on a 1.6 idi in another caddy, and it seemed to work pretty good, but it would be harder to adapt, since it has an odd three bolt flange for mounting. I had previously used a 1.5na manifold and fabbed an adapter which brought the turbo up to the top of the manifold. That ended up breaking, so I put the kkk turbo on that truck instead.

My question is then, has anybody put that big of a turbo on an ahu without running twin snails? Is it crazy? (Probably) should I do it? Basically, I have this one, or buy something else...

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Will the mapping of the m24s be realistic for a diesel? Or maybe only one would. Didn’t 1 spool up the other? Definitely not an expert, here....

-Todd

Honestly this is a question for a tunner. If you want to be eficent you will go with what a tunner can write for.

ToddA1 said:

Will the mapping of the m24s be realistic for a diesel? Or maybe only one would. Didn’t 1 spool up the other? Definitely not an expert, here....

-Todd

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That's what I'm not sure of. Is there any way to find out the map of any given turbo?

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Google or a 300zx forum would likely have the answers. The fact that you have the turbos and p/ns should make it easy. Then you’d need to be able to read the maps.

I know very little about the subject, but I was always under the impression that diesel turbos are speced to spool differently.

-Todd

My general understanding on turbos is that most turbos do the job. The issue is that stock gas engine turbos max out at 10psi at x cfm where as stock diesel turbos max out at 20psi at same x cfm (generally) its typical for diesel engine turbos to have a smaller ratio hot side to spool faster at low rpms as diesel car engines typically max out at 3500rpm power band vs the 4500 rpm that the equivalent stock gas engine does. Pound for pound it's better for diesels to have diesel turbos. These cars we are talking about here are old and turbo tech has come a long way in the last 20 some years. If your looking for stock to stage 1 to 1.5 tune performance area it's better to go with a tried and true tdi type upgrade. But if your upping the rpm limit of a TDI then a gas engine turbo or equivalent upgrade will be fine. If you can think of it its probably been tried in a tdi and a tunner like malone or kerma should be able to write a map tune fornit with some basic logging.

Egt management is a big deal for diesels so going with a slightly bigger turbo is usually best when doing any fuel modifications. Basically the turbo you are taking about might have issues flowing enough cfm at x of psi to combat this. It all comes down to the tune. Can you justify spending $300 on a tune for a turbo you have on hand vs buying a turbo that is not going to need a tune to work as properly. For instance the k03/k04 hybrid was a direct swap out and really no need for a tune to operate properly. I ran a gt2052 for a few years with a stock tune and it was a blast. Soon as I got my stage 6 tune from malone it turned into a rocketship with my 764s.
Food for thought.

If you can pull up a map chart you should be able to corssreference it with the typical ahu upgrades.
Imo the best upgrade for a ahu is to convert to a vtn17 because of egt management with decent fueling.
Again just about every turbo has been done. Might have to do some digging but you might find your answere deep in these forums

I know there's a tendancy to want to use something we have, but the road on this subject has already been paved several times by other people, at least from the perspective of electronic controls. G60ING and JFettig have both done a lot of work on the turbo side of the AHU / AFN engines and are worth reading in conversion forum or the performance forums.

If you're going to for non-electronic controls (aka MTDI) then it might be a different and you might want to stick with a wastegate turbo just to keep it simple.

I'm reading threads about this sort of thing right now.

Steve

Yeah, my thought now is that I can sell the m24 turbos (I have both sides) and that can pay for a good turbo that will meet my needs better. After a bit of research, I'm leaning towards a 1749 from a bhw Passat. Maybe I can upgrade the turbo on my Passat, and use that turbo.. [emoji848]
I've also got a lead on one, including the manifold for $200...

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Mozambiquer said:

Yeah, my thought now is that I can sell the m24 turbos (I have both sides) and that can pay for a good turbo that will meet my needs better. After a bit of research, I'm leaning towards a 1749 from a bhw Passat. Maybe I can upgrade the turbo on my Passat, and use that turbo.. [emoji848]
I've also got a lead on one, including the manifold for $200...

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I would be very leary of a used turbo unless i knew the person selling it and the miles were low and they documented the actual miles on it.

Steve