Quad turbo V8 + power limits??

Aragorn · Post by **Aragorn** » Tue Jul 21, 2009 3:52 pm

A T25 is imo far too large, and you'll just end up with a horrible laggy engine.

A pair of T25's will be good for 400hp and should spool up acceptably well from ~1.9L

Trying to spool a T25 or even a T2 from 1L just isnt going to work.

The smallest engine i can think of having seen a T2 on is the Metro GTi lump which is ~1.4L

You'd need to find a very small turbo suited to a 1L engine and the only one i can think of is the Charade GTti which used some IHI turbo.

Boosted LS1 · Post by **Boosted LS1** » Tue Jul 21, 2009 4:25 pm

It won't be laggy because it's a v8 with lots of exhaust and for 400 hp compression wouldn't have to be lowered to much if at all. T25's might just do it but would be borderline on a 4.6 imo. Saabs use a t25 for 200 hp. Personally I'd spec a pair of GT28 RS's as they'd have some reserve and a big punch or even ordinary gt 28's If going single it would be a GT 35 or GT37 depending on final Hp goals. A pair of gt28 rs make 400 hp at 16 psi on a pushrod ford v6

but will flow enough for around 500hp.

Aragorn · Post by **Aragorn** » Tue Jul 21, 2009 5:32 pm

Hes planning on fitting four of them

That means each turbo is being fed by two cylinders, meaning a horrible pulsed output of less than 1000cc is being fed into each blower.

Two T25's would work perfectly, which is what i said in my post. Four however, will not.

For more that 400, i'd go with a T28 from an S14A 200SX or Escort Cossie, as these are good for around 300hp when attached to their original 4 cylinder homes.

Boosted LS1 · Post by **Boosted LS1** » Tue Jul 21, 2009 5:59 pm

I think he was open to suggestions, he said.

V8James wrote:ok basically i want at least 400bhp
what sort of boost + turbos would be best for that power?

Hopefully he'll stick with 2 tubbies, 2 of these if using 25's. 22lbs air is right in the middle of the map.

http://www.turbobygarrett.com/turbobyga ... 6541_1.htm

stevieturbo · Post by **stevieturbo** » Tue Jul 21, 2009 6:05 pm

V8James wrote:ok basically i want at least 400bhp
what sort of boost + turbos would be best for that power?

Therein lies the problem.

You'll struggle to find 4 turbos small enough that they would be of any use for such low power.

And if aiming much higher, you run into the problem that to build a Rover V8 to last and make more power....would cost a clean fortune.

topcatproduction wrote: why the f would people want to spend a million quid on a Bugatti

As above, a RV8 isnt exactly a 1000bhp capable engine. Even in full Wildcat form, it would be pushing it extremely hard.

topcatcustom · Post by **topcatcustom** » Tue Jul 21, 2009 8:27 pm

What about using the turbo's minis/metros used, I know someone who has used one on all mini engines from 850cc to 1275, so 4 of those should be pretty much spot on shouldn't they? Plus I'd have thought fairly cheap, and couldn't you make ex. manifolds to feed 2 turbo's each after a collector to smooth out any pulses a little?

Not a turbo man, just thoughts.

stevieturbo · Post by **stevieturbo** » Tue Jul 21, 2009 8:32 pm

The old T2/3 on a Mini was crap then, and even worse now.

It was laggy and just made OK power.

The only real options would be 4 small turbo's from say a turbodiesel.

Realistically....how many modern turbos around now are fit for only 100bhp ??

Most, even small ones are 200bhp capable, which means with 4 of them on what is a relatively small ( only 2 cyls feeding a turbo ) innefficient engine, they could end up quite laggy.

V8James · Post by **V8James** » Wed Jul 22, 2009 7:06 am

So realy for a quad turbo set to work ok id need something like a dodge 7.2 or chevy 8.0 v8?

I have done a search but cant find any supplies for these
If i end up just having 2 turbo's then fair enough but would be nice to have 4

stevieturbo · Post by **stevieturbo** » Wed Jul 22, 2009 9:31 am

V8James wrote:So realy for a quad turbo set to work ok id need something like a dodge 7.2 or chevy 8.0 v8?

I have done a search but cant find any supplies for these
If i end up just having 2 turbo's then fair enough but would be nice to have 4

I dont know how efficient either of those engines are, but they would offer a more realistic proposition simply due to their size and they will shift more air.

If you can find 4 x turbos small enough, you could still do the Rover though. But it would purely be for novelty value and engineering. From a performance, cost and common sense ( ie value for money ) point of view it would be totally pointless.

Ian Anderson · Post by **Ian Anderson** » Wed Jul 22, 2009 11:52 am

What about the old "E" plate era Diahatsu cherade Turbo engine Tubro

It was used on a 999cc 3 cylinder engine and made over 100 bhp from memory

Ian

kiwicar · Post by **kiwicar** » Wed Jul 22, 2009 2:03 pm

Hi
Real steel will sell you a 502 chevy big block, everyone will tell you the block will fall in half with over 850 bhp being asked of it.. erm that is still alot of BHP. The crate motors are pretty low compression (about 9 to 1) mount the turbos in pairs so they see 4 exhaust pulses would be a good idea. Otherwise stick a 3.875" crank in a 4.155 bore SBC and you have 6.9 litres, that should big enough to be able to use 4 "normal ish" turbos (1.7 litres per turbo). forged crank, 72 cc chamber heads, and some decent pistons and rods and you should not need to do anything fancy beyond the plumbing. As I surgested before consider the 16 valve heads, the seperate exhaust ports could make this viable.
Mike

kiwicar · Post by **kiwicar** » Wed Jul 22, 2009 2:12 pm

Might want to look here http://www.araoengineering.com/pakages.htm
Best regards
Mike

V8James · Post by **V8James** » Wed Jul 22, 2009 10:11 pm

Looking at garrett site biggest id realy be able to for if i was to use 4 would be gt15 series

Boosted LS1 - nterested on your thoughts about 4 t25's being ok, trouble is theres always conflicting information + feelings which is why im grateful for everyones replies, Do you honestly think id get away with 4 t25's on a 4.6?
Reason being im trying to contact someone with a 4.6 with flowed + ported heads which ill stick a decent turbo cam in aswell

What sort of power will standard rods, pistons + crank on a 3.9 take? 4.6?

It would be nice to buy a fresh 502 but then thats big money lol along with them 16v heads, wow lots of cash

Boosted LS1 · Post by **Boosted LS1** » Wed Jul 22, 2009 10:44 pm

I'm suggesting you use 2 turbo's not 4.

V8James · Post by **V8James** » Wed Jul 22, 2009 11:02 pm

oh right sorry got my wires crossed slightly

on a 3.9 do you think id be able to get away with t to4e's /t34's with something like a .64 exhaust housing + still be ok?

If above would work out too big id probably be more inclined to for t28's instead of 25's