Inlet manifold runner design

[FarnhamStag]

Hi,
I have an Eaton M112 with water/air chargecoolers from a 2008 Jag XKR that I hope to fit to a 4.3 rover block (originally a vitesse 3.5) thats in a Stag. My problem is height, the std injection plenum had to be machined to fit under, so a custom fabricated manifold will probably be needed.
The only way I can get this to fit is to put the charger in the valley and fabricate the runners to bend immediately 90 degrees up between the heads and the charger. From what I understand any sharp bends here with a normally aspirated engine are a bad idea., is this still the case with forced induction.
I plan to run injection, 8-10psi boost compression was 9.75 but I now have composite gaskets which I guess bring things down.
Is doing this going to be a problem? If so will have to try a rotrex or similar but I really want the low down boost the eaton should provide.
Any advice would be helpfull.

Thanks

[DEVONMAN]

Hi,
I have an Eaton M112 with water/air chargecoolers from a 2008 Jag XKR that I hope to fit to a 4.3 rover block (originally a vitesse 3.5) thats in a Stag. My problem is height, the std injection plenum had to be machined to fit under, so a custom fabricated manifold will probably be needed.
The only way I can get this to fit is to put the charger in the valley and fabricate the runners to bend immediately 90 degrees up between the heads and the charger. From what I understand any sharp bends here with a normally aspirated engine are a bad idea., is this still the case with forced induction.
I plan to run injection, 8-10psi boost compression was 9.75 but I now have composite gaskets which I guess bring things down.
Is doing this going to be a problem? If so will have to try a rotrex or similar but I really want the low down boost the eaton should provide.
Any advice would be helpfull.

Thanks

Hi,
The same rules apply as NA. You could argue that the charge cooler will have a similar effect as 90 degree bends. The overall effect is that any resistance to flow will reduce the actual boost seen in the cylinders and therefore slightly less ultimate power output. It really depends on what you power goal is at 8-10 psi boost. At a CR of around 9.0 slightly less than 8-10 psi in the cylinder is probably not a bad thing unless you are using an octane booster. It's important to keep flow resistance equal in all ports.

Regards Denis

[FarnhamStag]

Thanks Dennis
I know it's a compromise, it's just how it will affect things. Another option would be to drop the intercoolers and mount directly on a manifold (Wildacat have a low profile injection version) and maybe try methanol/water injection. My goal is to have a nice tractable reliable road engine of with around 325 rwhp (mines currently about 220).
From what I can see thats not really achievable from a rover even taken to 5.3 without some seroius tuning.
If coming out of the ports at right anles (I have 45mm between the port exit and the side of the charger) looses say 5% from the ideal then thats probably OK, however if it makes 20% differerence then I need to look at other options.
What do you think?
Thanks again, Dorian

[DEVONMAN]

This is a difficult value to put a number on. With say 8.5 psi boost the best power gain would be 50% which equates to 330 bhp. Realistically with heat gain and resistance the efficiency could drop to 75% so power would be 300 bhp but in a very tractable engine.
With a boost of 10psi you may just achieve your goal.
Sorry I can't be more definite on this.
Maybe other have some views on this.

Regards Denis

[JP.]

Don't stare your self blind on boost.
More boost does not mean more horsepower.

Measuring boost is actualy measuring backpressure in the intake tract. Basicly measuring mixture that aint going into the combustionchamber.
So the more boost........the more is not going in.

I was running 7 psi with stock SD1 heads when I switched to Merlin heads.
With the better flowing Merlins boost reduced to about 3.5 psi but with more BHP at the wheels ( dyno'd).
So I replaced gears to run the blower faster at 8 psi to archive more BHP....

Cam profile can also alter boost, the hotter the cam the lower the boost but with a good profile it will also raise BHP.

What I am saying with this story, you don't have to run 10+psi to get horsepower.

Composite headgaskets will get you about 9.25:1cr.

What about running your Eaton upside down like Ford did with their V6 Thunderbird. You need to fab an intake that holds the supercharger in the valley from above.
Think this is a better option cause the V shape exit from the Eaton is not very well designed to run directly on the intakerunners. Spag tested this once with a smoke machine with bad results. Not all intake runners get equal fillings.

Water/methanol injection is a very good alternative.
Water if getting hot evapourates and goes into steam. While going to this form it takes a lot of heat away from its environmend. Water also cleanes your pistons and combustionchamber. So theres less risk on hotspots caused by carbon deposits on the piston. Hotspots can cause detonation.

Methanol also takes away a lot of heat ( even more than ethanol ) when vapourising.
Methanol also acts as an octane booster.

I am running this DIY kit Becoool
I am running it before the blower (Magnacharger 110) so it also cools my impellers.
As my 110 powers a 3.5 it has to run much more faster than your 112 on a 4.3 meaning your blower won't create lots of heat to worry about and your aftercooler will not cool but heat to about 85-90'C as its normaly plumbed in the cooling system.

[FarnhamStag]

Thanks, being playing around today and found I can use 40mm ID alloy pipe with a bend radius of 60mm that fits between the charger and the inlet ports, so although there is an immediate bend just at the inlet port entry hopefully it won't be too bad for flow?
the idea is to bring 4 equal length runners up to the top of the rocker covers where each will have water/air intercoolers, fed from the eaton from the top (as per the Jaguar). Injectors will be directly into the runners about 20mm from the port.
This still allows the hole thing to sit no higher than the original plenem.
My heads are TVR big valve derived from the 3.5 vitesse, so I don't know how much would be gained from the Merlin, intersting that you dropped so much back pressure though!
I've fitted a supercharger cam from V8 tuner, don't know if its any good
Hopefully the intercooler will remain cool the mainfold won't have any engine coolant running through it?
Are there many of you using the rover with a 112 eaton, there seems to be very few examples on the web?

Dorian