RS Motorsport :: Classic Speed Restored

Assuming additional fuel is not required during wot/max rpm and the current four injector fuel delivery is ample, is there any gain to be had by fitting an RS500 intake manifold over a standard (4 injector) manifold bar the increased throttle body diameter of the RS500 unit?

The question above is regarding a 450HP engine.

CheeRS,

Advantages for the RS500 part are;

More plenum volume
Larger throttle body
Better flowing elbow
Better high RPM mixing when switching to plenem injectors at high RPM

Unless racing in a specific class requiring the exact part it is considerably more economical to modify an original.

The best option for performance is too scrap the factory setups all together and buy/manufacture a custom manifold with optimum runner length and plenum volume.

My thoughts on this

JSA pretty much has it there,
Throttle body, elbow, plenum volume are big helpers, to gain extra power, the extra injectors are less important and are there as needed.

A lot of UK cars are now running side by side eight injector setups, this was developed I think by Mountune for WRC cars.

There are companies that also make spacers for the plenum to increase volume, this is a help.

However, IMHO the standard Marelli management at all levels (including L6 with pectel boards) is a bit ancient, and can be bettered.
All the top power cars (most from the Skandinavian boys) are running custom plenums, 1000cc Siemens injectors, and custom management, (Motec, autronic etc) these I think are much more tuneable, and capable of much greater results

As for maximum power available from standard single injector setups on Marelli management, we have seen a few running up to 450 crank bhp, with the right injectors.

I believe more would be possible without too much difficulty (bigger injectors/fuel delievery system, even more boost etc), but making it a refined useable tune is the hard part with standard management, at that level they are getting a bit crap at low speeds/ idle etc, so it's Ok if you just want a HP figure to brag about, but crap if you want a fast car.

So if I wanted much more power from my car, I would not be wasting my money on genuine RS500 inlets and management system, I would instead be investing in good management, and a custom plenum, or spacer for the one I have.

There are 2 RS500 items that do work very well though, a genuine RS500 intercooler is on of the best available, and the exhaust manifold (same as 3door RS cosworth) is also good for above 420bhp, there are 2 types of manifold, some are thicker than others, both work the same, the thicker one is stronger.

The RS 500 block is also very strong, as is a new 200 motorsport one from Cosworth, if I was building a fresh 400+BHP engine it would be first thing on my shopping list.

Spotted these on another forum.



















Quote.....................

from the off i decided i wanted an engine that would rev but still be quite responsive so rather than destroke the engine to get the rod length to stroke ratio right i decided to increase the stroke. now, when you stroke a yb you normally end up with a less than ideal ratio. what you need is a MUCH taller block enabling a longer stroke but also more importantly longer rods...... much longer rods! the millington engine had a 8mm taller block but even that is not ideal for what i wanted so i had to make my block taller. in simple terms i have added a spacer on top of a 200 block and then linered through both parts...ping, tall block! now all that seems simple but believe me it's not, there's a lot to consider!

for the moment here's what i want to reveal about the new donkey....

* it's more than 2200cc
* the rods are just under an inch longer than standard
* the crank has a longer stroke
* the bores are larger than standard and are nicosil coated
* the head has big ports, big valves, solid lifters and spunky cams
* the inlet manifold is made up from an m.i.s. mag plenum, jenvey individual throttle bodies and a jenvey manifold which had to be chopped and welded to get it under the bonnet!
* turbo spec is secret for now as 2 were tried and one was chosen
* the engine misses the bonnet by 5mm Surpris
* it has loads more potential for extra power
* the dyno figures are 100% accurate, some might claim more but reyland horses have always been strong!

........

734hp and 500ftlb uncorrected

702hp and 490ish torque corrected

oh and it makes full boost by 4000rpm..

John I'm amazed you didn't see it
Look at photo number 5 of the exhaust side of the engine and the turbo
Theres a 20-25mm thick spacer between the block and the head

Danny 0409 470055