extra14

I`m running a cosworth v6 engine on standard compresssion (9.7 to 1, I believe) , with sequential twin turbo. (T3, ihi RHB5 turbos).


What I want to know is what is the maximium boost i can run safely, i have been told 8psi. Anyone here running a turbo V6 on standard compression?

I will set my display to inject water at 4psi 35C.
If I set water injection to be on regerdless of temp at say 7 psi for detonation control will I be able to up the boost much?
I plan to use 0.6mm water jet at 100psi.

Thanks
Darren

JohnnyB

hmm its getting close at standard mate.

I have heard 9 psi is the limit, but water injection will help

JohnnyB

Looking at your other posts for upto ish 400 bhp you can use machined standard 24v pistons as they are very good

its the blocks which like to crack though so watch you RPM

extra14

Thanks, i want to keep the rpm standard at around 6- 6.5k, I was looking to get the pistons machined, some have told me that they are very good for maching.
Is there much meat to machine the pistons?
I`m looking forward to putting this engine in and getting this going asap, i might buy another one to machine the pistons.
Have anyone changed the timing chain? Is it easy, its for a BOA engine.

Does anyone know where to get pistons or rods for this engine, i might look for slightly shorter rods to lower the comp ratio.

Thanks
Darren

JohnnyB

There is enough meat to do a 8.ish to 1 compression ratio, you can get forged pistons for the engine, which works out at Ł800 ish, but you will still have to machine them.

The con rods are strong enough for 600bhp and I think the crank is fine for that bhp.

The timing chain is not difficult you can do with engine in place.

what fueling are you using eg mangment and injectors?

extra14

I`m using my own ecu i have designed, with edis ignition and wideband controller.

I will get some 2nd hand cosworth green injectors or use band new injectors with the same flow rate as the greens but with a slightly lower resistance (they will open a bit quicker).

I might machine the pistons for 8.5 to 1 or i might run standard comp ratio, low boost. When i change the clutch (not much meat left on it) i will lower the comp ratio.

I will modify the manifolds, done the offside already need to do the nearside now.

The turbos will mount infront of the engine.

Thanks
Darren

JohnnyB

what car are you putting it in.


Judging that you are placing the turbos in front a capri?

o have you got any more information on you ecu as I am looking at changing mine

extra14

Hi, I`m putting it in a kit car (actually a car i`m building from scratch)
It will have the turbos at the front as the engine actually is very far back - making it front mid engined!
The ecu will have 12 (map) * 8 (rpm) points to program for fuel and ignition using the edis module.

It will have boost control, rpm based a high and low setting.
Water injection and nos. I am currently redesigning and should have my next prototype soon.

Thanks
Darren

JohnnyB

Darren do you need a external tester for you ECU

lol

sounds good mate

keep me uptodate mate

extra14

LOL!

I have a friend that needs his done soon, i`ll consider when i`ve moved further in development. What are you going for N/a still or turbo?

Thanks
Darren

AlexF

sequential?

as in one turbo feeds into the next?

alex

extra14

No one turbo gets 100% of the exhaust. The other turbo is blocked off at the turbine outlet end, and the inlet is blocked.
Then both turbos are running and the inlet valve is opened.
The old mazda rx7 had this sort of system.
The primary turbos is the ihi rb5, max power 150 - 180. That is less than what the engine provide n/a so this turbo will stop at 3000 rpm.
Should boost from idle though - Lag whats that then?

JohnnyB

Not sure yet Mabe n/a, but most liky twin turbo setup

extra14

Decided to get the head modified to reduce the comp ratio. The heads will be 1 - 1.6mm higher than standard. Does anyone know if it will present a problem when fitting the timing chain?
Thinking i might need to modify the timing chain tensioners?

Thanks
Darren

JohnnyB

Thats not the way its done mate, but I think the tensioners will be ok

Jim Galbally

when you mod the heads for a higher CR you take meat out of the combustion chamber, you bdont change the height of the head itself.

Jim Galbally

sorry i mean when you mod for a LOWER cr.

when you want higher you do indeed skim the head down

extra14

Yes i will try to get the combustion chambers modified to have a higher cc. Spoke to a garage who say they add a metal plate to the bottom of the head for 75 quid a head, probally will be cheaper than getting the combustion cahmber modified. I want to keep the pistons untouched for two reasons:
More meat means stronger pistons
It will save me from having to strip the bottom end.

Having said that i can get the heads ported at the same time.

What boost will i be able to expext at 8 to 1? I`m hoping for 15 - 22psi, should be more than enough power as it will have the mt75 4x4 box on it.

Thanks
Darren