Why Were Twin Turbos Abandoned?

[sdg3205]

Back in the mid 90's when I used to subscribe to the DOA, and it's publication "DeLorean World," I would read at least one ad per issue advertising twin turbo upgrades.

If my memory is correct, it was Don S. in a DMC jump suit in the ad.

So why were twin turbo setups abandoned in favor of the Stage Series engines?

When I bought my car one of the pieces of paperwork that came with it was a copy of that classic ad with some numbers scribbled at the bottom. Clearly at some point a PO of 3205 was pricing the twin turbo setup.

Was it maintenance? Reliability? Cost? I've never been clear on why the turbo route was shut down, but if for the same price you could get a Stage II (at 156 whp) or a twin turbo (@ 200 whp) why not a turbo?

[opethmike]

Reliability; the internals of the stock DeLorean PRV are not very forced induction friendly.

[sdg3205]

Reliability; the internals of the stock DeLorean PRV are not very forced induction friendly.

Which internals were prone to failure, Mike?

[08087]

Doesn't one of the Renualt models use a twin turbo set up??? I don't recall hearing any issues with them.

[louielouie2000]

Which internals were prone to failure, Mike?

The pistons are cast, not forged. This makes them especially susceptible to forced induction.


Doesn't one of the Renualt models use a twin turbo set up??? I don't recall hearing any issues with them.

Cars like the Renault Alpine almost certainly had forged engine internals. :)

[opethmike]

Louie beat me to it. The piston rings in the stock DeLorean PRV aren't particularly beefy either.

Slight correction to Louie's post - All PRV connecting rods are forged. It is the pistons in our engines that are not.

[TheDutchTexan]

Unless someone forges a PRV (are there even forged parts available?) I doubt a true high output turbo or supercharger PRV will ever happen.

[opethmike]

Unless someone forges a PRV (are there even forged parts available?) I doubt a true high output turbo or supercharger PRV will ever happen.

Fair enough, but outrageously large amounts of boost are not necessary to turn a DeLorean fast. 250-260 horsepower and a D is VERY fast.

[dmc6960]

Unless someone forges a PRV (are there even forged parts available?) I doubt a true high output turbo or supercharger PRV will ever happen.

Yes, Ed at DMCEurope has had high compression forged pistons, and low compression forged pistons made. I have the high compression ones in my car right now.

[sdg3205]

Fair enough, but outrageously large amounts of boost are not necessary to turn a DeLorean fast. 250-260 horsepower and a D is VERY fast.

and you dont want to start blowing up your tranny.

[DMC3165]

and you dont want to start blowing up your tranny.

I remeber hearing somewhere that anything over 300 HP would be too much for the stock DeLorean trans. Especially the input shaft and front main bearing. I think that's being discussed in the other thread about the legend parts.

[DCUK Martin]

The pistons are cast, not forged. This makes them especially susceptible to forced induction.

Cars like the Renault Alpine almost certainly had forged engine internals. :)

Actually the vast majority of production turbo engines have cast pistons. The difference is that they're designed for forced induction ;-)


Louie beat me to it. The piston rings in the stock DeLorean PRV aren't particularly beefy either.

The top ring on the Z7U is 0.5mm thicker. That's the only difference.


Unless someone forges a PRV (are there even forged parts available?) I doubt a true high output turbo or supercharger PRV will ever happen.

Venturi 400GT - 400hp twin turbocharged 3.0 litre 24V PRV

http://www.evo.co.uk/images/front_picture_library_UK/dir_618/car_photo_309454_25.jpg


I remeber hearing somewhere that anything over 300 HP would be too much for the stock DeLorean trans. Especially the input shaft and front main bearing. I think that's being discussed in the other thread about the legend parts.

5th is actually the weakest link, but you have to be in it to break it. Then it's the input shaft. 300hp and 300ft-lbs is about its limit, yes. You'll slip a standard clutch long before that point though!

[TheDutchTexan]

The 3.0 24v PRV that makes 200 stock, it also has more displacement. Those extra valves are going to make it a whole lot easier to breathe at higher rpm.

So the stock transmission tops out at 300-300? That is actually pretty beefy considering it only has to deal with about half that. I am not surprised 5th is going to break under load. It is supposed to be the cruiser gear in any car. 03-04 cobra's have a problem with 5th and 6th when they are running high horsepower.

My mustang doesn't pull at all in 5th, I've had it to 145 (limiter). But it gets up to ~140 in 4th. You are already flying at that point. Most fun is 0-100, and that is achieved with the first 3 gears alone in my stang.

What is top end in 4th in a DeLorean?

[vwdmc16]

20.71 mph per 1k rpm in 4th so:


calculated its 124mph @ 6000 rpm in 4th
134mph @ 6500 rpm

26.63 mph in 5th

so 160 in 5th @ 6k
and 173 @ 6500


If 5th could hold that power required to reach it:tongue2:

[vwdmc16]

also the 2JZ swap delorean is still running the UN1 trans ( with a stronger input shaft and now a Quaife LSD) and hasnt had a failure yet with the 395 WHP( +/-475BHP). this was under drag race conditions as well the owner claims.

But im thinking this was a rare unique achievement and dont expect all D trans to handle that power

[TheDutchTexan]

124 in 4th? Not too bad at all. 160 is flying!

I would guess the supraD would only utilize 1-3, maybe a bit of 4th in the quarter mile run. Maybe he doesn't bang gears / power shifts. If he does all that his transmission might be one of those flukes. Either that, or we are not giving the transmission internals enough credit.

Quaife LSD you say? Guess a DeLorean is a one wheeled wonder stock?

[vwdmc16]

not at all, its doesnt have the power to spin them well!;)

even in slick conditions the tires at least on my car spin evenly, remember the rear tires are relatively wide and have most of the cars weight on them. but im sure even with mild power upgrading a LSD of some kind will do wonders however with stock power you wouldnt ever notice it