B B C 5 4 0 T W I N T U R B O Q U E S T I O N S

[hannes_slanec]

Hello, I would need some help with my 68 Impala with 540BBC twin turbo project I hopefully will introduce in the project thread soon.

How can give me some hints what leight and not tooo expensive turbo is the right one (trim, A/R, housing, size and so on...)

The turbo shall make not more than 6-9PSI of boost and not earlier than from around 3500-4000rpm (Redline is 7000rpm).

My expected HP rating is around 1000HP, I would like to reach a 3,5sec 0-60 time.

My compression is not that low with 9,2-9,5:1 (depends on the head gasket I will go with) but that car needs to be streetable and therefor the mileage is important.

7 or 8:1 would make the mileage suffering.

Also a nice cam advise would be appreciated, the car will go with a modified Vortec 7400 EFI.




Thanks in advance

Hannes Slanec

[bentfab]

Contact Tom Nelson he is the twin turbo mad man. Or go to his web site: www.nelsonracingengines.com
He's a site sponsor

[hannes_slanec]

Thanks for the hint but I fear he will not have the time to help someone who cannot afford to buy an engine from him.

I live in Austria, the transport and tax alone would cost more than the engien itself (we have tax up to 65%).

Thanks Hannes

[Payton King]

540 ci BBC twin turbo and gas mileage are mutually exclusive.

[hannes_slanec]

I knew that that statement will come as it comes always from somebody but it is a difference if I need 20 liters of gas per 100km or 45 liters .

There is no need to talk about any further, any engine got a fuel consuption range from / unitl, it depends on many factors what the mileage is finally.

An carbureted, hot camed, low static comp. engine with a high stall speed, 4.88 gears and a food that is down on the floor most of the time will need more than a fuel injected, properly tuned, mild camed, high comp. engine with a low stall speed, 3.08 gears and a driver who push the padel once in a while, even if they got the same displacement.

And I just want to be on the lower side of the range of an 540cid engines fuel consumption.


Hannes

[TOM NELSON]

A mid frame 88mm i would probally use that way it's not coming on boost to fast.And will be better on mileage The 88 will be able to make the 1000hp you looking for.You can find them rebuilt pretty cheap i'm not sure of the supplier but ive seen them for as little as 700.00 rebuilt.Hope that helps

[hannes_slanec]

Thanks Mr Nelson, it helped a lot but if I understood you right you talk about a single turbo setup, right?

What means midframe?

By the way thanks for your nice videos, you give a lot of passion in it and it is visual.

I love the sound of the 427 TT video of Antony Keatings engine (What Antony Keating is that, the Leader of Red Hot Cillie Peppers?)

What injectors would I need for a very mildcamed and streetable 540 TT and what would be a good cam for mileage for your opinon?

Thanks so far Sir!

Hannes Slanec


Ps.: I added a Photoshop-Fake of my Project, although I dont think I can go with 20´since I will have traction problems anyway, so I will go with 18´s and more sideheight since a lot of people told me that will make my 0-60 time far better.

[hannes_slanec]

A thing that would be even more interesting is a quad turbo setup since the smaller turbos are more easy to get and they can be mounted with less distance from the cylinder head.

Headers for a quad turbo would be very easy to make only two bows from two exhaust ports up to a flange and the turbo on it, done .

But what would be the right turbo for a 540cid engine?

Any suggestion?

Thanks Hannes

[hannes_slanec]

By the way, I could not find anything in the web with mid frame turbo.

What means mid frame?


Hannes

[TOM NELSON]

This what i would do run two injector per cyl.One 36lb and the other a 55lb the 36 will give you a good spray pattern and nice drivabilty they are cheap also.Stage the second set two come in at around 104 kpa when boost comes in this will improve your mileage quite a bit because you'll be able to run real lean in non boost conditions.As far as turbo arrangements i'm going to give you a secret.Make your firing order 18726543 it is not exspensive to do most cam companies will do this for you then when you build the headers try y or join 2&8 join 4&6 take those two and join them togethor do the same for 1&7and 3&5 and run them togethor take these two and run each of them into a split housing Single 88mm turbocharger.You should get what your looking for and then some.I wouldn't doubt you could see 15mpg and still make 1000 easy.Cam specs should be in the high220 at .050 range with around 115 center.Hope that gets you going