Quad turbo V8 + power limits??

V8James · Post by **V8James** » Mon Jul 20, 2009 10:07 pm

Hi all, i new on here

Seen a few people having twin turbo V8's
Ive just been thinking about goin down the route of quad turbo conversion on a 3.9

Engine will be in the back of a project car + space is not an issue
Would this work?

If so what sort of boost + power am i limited to on a standard engine?
I know the benefits may not be much more than just twin turbo due the size of the turbos id need to run but it would be a smart conversion

Also would i be able to run this on standard injection setup with some ecu mapping + different injectors etc?

Cheers in advance
James

Boosted LS1 · Post by **Boosted LS1** » Mon Jul 20, 2009 11:00 pm

You need to read up on this subject as if you go forward you'll need a custom engine build and installation.

V8James · Post by **V8James** » Mon Jul 20, 2009 11:32 pm

Building the engine isnt the problem nor is fitting it + bracing verything well enough its just firstly does it work well? WHat to do about fuelling etc

Is there anything on here about it?
Did a search but couldnt find anything

stevieturbo · Post by **stevieturbo** » Mon Jul 20, 2009 11:42 pm

Aside from novelty value, it would be a complete and utter waste of time and money, and offer no benefits over a decent twin setup...or indeed a well designed single setup.

And be a total nightmare to package and complete.

So apart from the novelty of it....Why would you consider this ?

stevieturbo · Post by **stevieturbo** » Mon Jul 20, 2009 11:43 pm

V8James wrote:Building the engine isnt the problem nor is fitting it + bracing verything well enough its just firstly does it work well? WHat to do about fuelling etc

Is there anything on here about it?
Did a search but couldnt find anything

IMO, fueling and ignition are the very easy bit, the installation and packaging and parts selection would be the mega expensive and difficult bit.

There are dozens of options for controlling fuel etc.

Eliot · Post by **Eliot** » Tue Jul 21, 2009 6:16 am

As others have stated, there is no benefit over a twin or single system apart from novelty value. Plus its nothing new - there's an 8 turbo V8 out there:
http://www.lateral-g.org/sandlin/

On a std engine, aim for around 6psi boost. For all the calculations, just divide your flow rate by 4 to work out what turbo you need.
4 x T2's would probably work - try to think of turbo's that were fitted to engines in the 1-1.2L range with a 1/4 of your power goal - which would be something around 300bhp on a std 4L engine.

Bin the prince of darkness ECU and run aftermarket such as Megasquirt etc.

topcatcustom · Post by **topcatcustom** » Tue Jul 21, 2009 8:09 am

Well I'm gonna go against the flow of discouragement and scorn- if the guy has the funds and will to do it why not?! Its not like everything in the world is done for a 'sensible' purpose, or why the f would people want to spend a million quid on a Bugatti to look at in their garage and do 500miles a year in- they should just buy a ford mondeo it does the same job after all on the road yea?!

If you want quad turbo's, like the others said you wont get much benefit over twins but it would look and sound the nuts, and still be potentially as quick or quicker if you went all out with it in the future. I'd love to see it anyhow and if its not being used as a pure drag or race car then there is no reason not to go with the idea whatsoever- just be aware that it will cost you more!

We should be encouraging mad builds not knocking them back!

TC

p.s. if you dont have an engine yet, I'd say either go for a bullet proof X-bolted 3.5, or a big capacity 4.6>, of course your funds determine the choice!

Ian Anderson · Post by **Ian Anderson** » Tue Jul 21, 2009 8:33 am

Go for it

Nothing worse than not trying!

I heard about a Golf that had been done with a turbo and the bloke was worried about under bonnet temperature so he fitted the turbo under the rear bumper and then ran the pressure pipe all the way back to the engine.

Some say "won't work" actually it did and the extra volume of the pipe acted as a pressure canister so the turbo lag was a lot less pronounced

Off the wall thinking yes bu why not!

Ian

V8James · Post by **V8James** » Tue Jul 21, 2009 12:09 pm

Thanks for the replies + support

I completely understand why some are saying dont bother which on one side i would tend to agree due to the extra effort/money compared to benefits over twin setup

People where i am have got little projects which although they think the world of + are good they are nothing special which is what leading me to this

Im ok fabricating the 4 manifolds + was thinking of using 4 t25's which are still smallish but will also work happily at 15psi

Megasquirt looks to be the way for fuelling on what others have said

What sort of power can be forced into a standard 3.5/3.9

If i was to run with 15psi, correct pistons rods cam etc + standard heads what sort of power could be expected with 4 t25's at 10psi?

Sorry for the questions
James

Boosted LS1 · Post by **Boosted LS1** » Tue Jul 21, 2009 1:20 pm

About 270 - 300hp. Is it really worth the effort? Why not start with a bigger engine and blow that.

spend · Post by **spend** » Tue Jul 21, 2009 1:25 pm

Thats what I said Doris!

Boosted LS1 · Post by **Boosted LS1** » Tue Jul 21, 2009 1:26 pm

Go away Mavis and get yerself a cup of tea.

kiwicar · Post by **kiwicar** » Tue Jul 21, 2009 1:40 pm

If you went SBC you could get a set of aero 16 valve heads, the reason I mention that is they have 8 exhaust ports per head, it would make it possable to make up a manifold for each turbo without any silly branching or just using 2 cylinders per turbo.
Mike

V8James · Post by **V8James** » Tue Jul 21, 2009 2:25 pm

ok basically i want at least 400bhp
what sort of boost + turbos would be best for that power?

Boosted LS1 · Post by **Boosted LS1** » Tue Jul 21, 2009 3:21 pm

You need roughly 600 cfm for 400 hp so can divide that amongst your turbo's. Then check some flow charts.

The bigger engine will be a better starting point hence a 4.6 or thereabouts which will get you to 400 easily enough with 1 correctly sized turbo let alone 4 tiddlers. A stock 4.6 has good pistons and rods as standard. Early rovers have very weak pistons so I'd leave those alone.