EVIL ENGINE goes Twin Turbo - Your Chance to Design the 930tt Exhaust System

[RarlyL8]

Took a few pictures this morning.
Views from the sides and bottom give a good idea to the placement of the turbos in relation to the engine.

I will take some measurements for engine bay fitment as soon as my exhaust system cools down. (Went for a drive this morning, WOW does cold air light up the rear tires!)










Here is a picture that gives an idea of what type of muffler system may be possible. You will notice that the K-24 turbos are located futher back than the stock 993tt K-16s.

[RarlyL8]

Luke - I've got some bad news.
The passenger's side turbo will actually hit the oil tank in my '78 SC. You need 6" of physical space and you only have 5.5" available. This measurement was taken from the top of the lower valve cover on the 2nd stud from the rear of the car.
If you use your '72 setup all these problems should go away. Mark Hargett would be a good consultant on this issue if you have not already spoken with him.

The good news is the driver's side fits perfectly.

If you do not need any more info I will disassemble the 993tt system and get the exchangers shipped back to you early next week. Thank you for letting me borrow them.

[Lukesportsman]

Brian,

Can you clarify or sketch the clearance issue mentioned with the oil tank. You mean 6" to contact and therefore you'd want more to not boil the oil? Which direction would you need to move it to help fix this? Could I just borrow that large hammer on your bench?

Sadly you've given me the news I needed, but didn't really care to hear. I guess I could just buy another 72' Hehe or go to a trunk mounted oil tank. Do you think there might be a reason most guys go with one big turbo

You've been a great help with this one detail. It might help in my selection of chassis or at least the build plan. A 964 chassis is looking more and more a possibility to move the oil tank and for room for the 930 box gaining all the other suspension advantages too. Nothing solidified there for sure.

[RarlyL8]

The cold side housing of the turbo will come into physical contact with the oil tank.
In order to avoid the contact you would need to move the turbo back several inches which gets into all the oil lines. The tank needs to be moved and all the oil lines with it.
I have seen very few pre-993 cars with side mount twin turbos. I guess now we know why.
Can you not use your '72 for the twin turbo chassis and put the EFI motor in your other car?

[red9]

Brian, Luke-- I just found this thread .Very interesting. I have had(recently) this type if engine in single turbo cofig and did much of the theory you are going thru. I have 993 ( one GT 2 race car and one as street car currently being converted to GT2 2 W/D) and have had various other 993 engines ,including the intent to convert N/A to twin turbo.I suppose I should say I also have vatious 996.
I am not technical but I ask a lot of questions and can measure things! Re issue of 993 case -- fundamentally no difference to TT and N/A cases and are interchangeable. Heads are different with the later cars from 993 TT pistons higher(into head) Earlier (965) set up is like N/A engines. Crank from 964 is better choice than 993 N/A. To this day I still cannot be sure if 993 N/A crank is different to 993 TT--- authoritive answers both ways.The clearance on 993 TT is an issue .996 TT turbo position is virtually straight opposite exhaust ports and that engine manifild will not fit 993-- let alone earlier car.

[Lukesportsman]

Red 9:

Are the factory GT2 headers similar to the 993TT or are they relocated like Brian's photo above? Its not an option for me, since I've got too much invested in these, but for future TT aspirers.

[red9]

Turbos finish in the same place-- rule requirements dictate- I yhink that is a reason but original set up was/is very effective.

[WydRyd]

Originally posted by RarlyL8
The cold side housing of the turbo will come into physical contact with the oil tank.
In order to avoid the contact you would need to move the turbo back several inches which gets into all the oil lines. The tank needs to be moved and all the oil lines with it.

You can fit the turbo there. You just need to relocate the inlet to the oil tank and make a bracket to kick out the bottom of the oil tank a little. Protomotive's been doing this for years in their TT conversions.

[JeffreyNMemphis]

Brian,

This thread has been idle for a while. I know you are busy with other stuff. Is there anything new? Did you ever make a final decision on where you intend to mount the turbos? Which heat exchangers etc.?

[RarlyL8]

Yep.
The turbos are going rear mount and the Monster exchangers will be butchered to accommodate.
The only change lately was that the engine tin has been painted and is ready for the tin snips.

I've been in overdrive for several months now getting the muffler deal going. I will return to the dark side .............

[mic]

Brian:

That is the way I am going as well. I have just buchered a set of 930 race headers to help build a wicked set of TT headers (cut them in half), twin T03s at the back. With the I/C that i am using this is the best configuration. Pics to be posted later as the project progresses.

[RarlyL8]

A new option has surfaced for the twin turbo headers - true heat exchangers.
The equal length primaries are optimal for off-boost torque which is fantastic for a street engine. SSI quality is unmatched in the industry as well which is a huge plus.








And here is what the Evil Engine has been up to lately:

[9dreizig]

Bryan, is it your intent to offer a complete "kit" to TT a 930? if so when do you think it will be available ? I know you've been busy with other things lately

[RarlyL8]

Don't even think about it! Ha!

I want to get back to that project sooooooo bad. I figure it'll take me a year to prototype and develop the product line I have chosen before I can start to breath again and get back to the tt project. A few more months and I'll be there.

In the mean time I'm using the knowledge gained through the exhaust business to apply to the tt project. SSIs look to be a given.

[9dreizig]

Sweet!!! I should be ready to be one of your guinea pigs by then!!
what turbo's are you thinking ?

[viper4490]

nice

[9dreizig]

Hey Brian, are you going to be around the latter part of Thanksgiving weekend ? I'm driving my 86 turbo from NH to Reno and will be passing through. .Since I originally bought it in AL it probably would like to see your state again ( plus trying to stay out of snow storms on the northern route).

[RarlyL8]

That would have been great but I'm going back to IL for Thanksgiving.
My wife still has family there. All of my family is now moved down here enjoying NOT shoveling snow!

I hope you did not misunderstand, I do not plan on making a kit.
This is purely an exersize in the possible for no other reason than I can do it. I have seen first hand that twin tubos on these cars offer no advantage over a single. Modern turbos are incredible.
I will list every part I make/use so anyone can copy the layout should they choose to. Being that the fuel injection system will remain CIS it is doubtful that anyone else will go that far.
I plan to use the stock K16 turbos.

[9dreizig]

Brian, I'll have to stock up on leftover turkey at my brothers house!
So if you don't think there will be an advantage why do you think Porsche does it on the OEM lever? Surely not to see if it can be done? Cost ? Not turbo lag ?

[RarlyL8]

Honestly I don't know. If I were to guess I'd say that the requirements for a DOT stock vehicle of 3.6L+ might be the reason. Twins allow you to squeez out the last ounce of turbo lag.
The boxer engine lends itself to the twin configuatation as well. There is more room in the rear for mufflers and cats if you put the turbos on the sides.