S54 stroker kit

[_Nathan_]

I was assuming same chassis so twisty bits should be the same in both imaginary cars, likewise you can assume that the gearing would be matched to the engine through a different gearset and \ or final drive. I was simply wondering if a more torquey 3.4 engine revving lower might potentially be more reliable than a 3.2 screamer making exactly the same power?

F1 engines are limited to 18000 rpm so the Renault can't rev past that and I assume all others would rev to that same limited maximum? I suspect a lot of Red Bull's dominance is not to do with the engine (after all Renault also have a Renault engine) but simply that Red Bull have got Adrian Newey...

[The Gorilla]

Hi,

Nathan- equal cars, around a Track, save the engines.

Revs on the S54 is good.

A stroker kit does not give you revs on the S54.

Regards,

The Gorilla.

[Rutkowski]

Gents - i meant 0 - 160km/h in 10.8 seconds, sorry.

As for the 'stroked' S54 - i personally have given up on this idea. It'll be Schricks 288 / 280 with larger throttle bodies and CSL exhaust valves.

[NZ_M3]

Originally Posted by _Nathan_

I'd have guessed that a 3.4 producing 420bhp might be a little less stressed than a 3.2 producing the same though? Less revs may well mean better reliability which could be seen as a good attribute in a race car.

I may be completely wrong though!

You are Nathan.

All to do with Rod stroke ratio and how square the motor is.

The perfect rod stroke ratio is 1.75:1 if I remember correctly

Then you get into over square and under square rod stroke which exerts different type of stress on different areas of the motor. As a general rule, an over square motor stresses the crank and an under square motor stresses the cylinder (if memory serves haha ..)

Originally Posted by The Gorilla

Stroking reduces revs

Shorter stroke Engine would rev much quicker,
and the longer rods would increase the engine torque.

Without looking up on rod stroke ratios of the S54 that's not entirely correct Mr Gorilla - see my above reply to Nathan.

An under squared motor is good for revs and an over square motor good for torque.

Is the S54 over or under squared?

Originally Posted by _Nathan_

I suspect a lot of Red Bull's dominance is not to do with the engine (after all Renault also have a Renault engine) but simply that Red Bull have got Adrian Newey...

Hitting the nail on the head !! Red Bull without Andrian Newey's designs = mid field in F1 even with Vettle behind the wheel.


And just to be a little bit on topic ... if I wanted to go faster in the CSL, I'd pull the S54 out and put the S85B40 in. Lighter motor, sits further back than the S54 and instant 420hp without stressing the motor. Then I'd take as much weight out of the car, corner balance and slap the best suspension I can get my hands on and spend a lot of time setting it up.

[The Gorilla]

Hi,

Rod ratio should ideally be between 1.7 - 2.1.

Oversquare is where piston diam is greater than stroke,
and undersquare is the revearse.

Stroking will always reduce the max revs of
an engine due to the vibration and resonance
created at the crank due to using long rods
with what is already quite a long stroke.

Longer rods reduce the side load into the bores
as the crank/rod angle is reduced, but the trade
off is that longer rods flex more and thus harmonic
vibration increases.

Harmonic resonance will destroy an engine in secs.

The S50 B30 [E36 3.0ltr] is claimed by many Racers
to be the better engine than the S50 B32 [E36 3.2 Ltrs].

Vanos aside, the reason is that the 3.0 is 85.8 mm stroke
with 85.5mm bore V the 91mm stroke of the 3.2.

The ''short stroke'' 3.0 ltr when fitted with the 3.2 head
which has larger ports, thus better flow capacity makes
for a much better Race engine than the 'stroked' 3.2.

The S54 is 91mm stroke with 87mm bore thus if it
was De-stroked to 85.5mm with the 87mm bore it
would be just under 3.0 ltr but would pull, with the
correct internals, circa 9000 rpm.

Although the rod length of the short stroke [3.0ltr] S54 would
increase from 139mm to 144.5 this would give a Rod ratio of
1.66.

To take this one stage further, you could raise the wrist
pin in the pistons, use a short skirt piston to reduce
friction and thus help with piston cooling, move up the
top piston land [ring] by 2mm towards the piston deck,
anodize the top land to assist with
piston cooling, and then use a longer rod at say
149mm which would give you rod ratio of 1.71.

You would then have a 3.0 ltr S54 with a 1.71 rod
ratio which would be oversquare and rev to 9000 rpm.
Short stroke with long rod.

I would take that over a Stroked S54 anyday for Track work.

Even the S65 is a ''short stroke' V8.

It does not make much more Torque than a good S54 but
it will and does rev.

Regards,

The Gorilla.

[glendog74]

My head hurts

[AlexGTT]

Originally Posted by glendog74

My head hurts

Mine also.

I agree with Gorilla. I use the same principles when redesigning historic race engines in my work. We reduce crank stroke, move wrist pin hieght up, have short skirt pistons and slightly longer rods. Only difference is we make short deck blocks because the stoke is so much bigger than bore and we are fighting to get as close to square as possible but try to stop rod length going crazy. The engines I work on were designed to be very torquey with less concern for outright power.

This make the motors much better at higher revs and greatly increases engine life.

[DuncanR]

Originally Posted by The Gorilla

Hi,


The S50 B30 [E36 3.0ltr] is claimed by many Racers
to be the better engine than the S50 B32 [E36 3.2 Ltrs].

Vanos aside, the reason is that the 3.0 is 85.8 mm stroke
with 85.5mm bore V the 91mm stroke of the 3.2.

The ''short stroke'' 3.0 ltr when fitted with the 3.2 head
which has larger ports, thus better flow capacity makes
for a much better Race engine than the 'stroked' 3.2.


The Gorilla.

Im looking at getting something similar i think, not being very clued up on BMW's of course, this from an email i received about my possible E36 M3 GT project quote.

"The engine mods were done by ??????, putting an Evo head and pistons on 3 litre crank and block, and shrick cams. Good for 340 bhp or so. ?????never thought of doing it himself so rubbished it. Those modded 3 litre engines are gems and are unburstable."

[Thorney]

Yeah Gorilla has the point, most E36 racers prefer the mixed unit of 3 and 3.2 combined, nit event hat expensive.

We looked into stroking the S54 and came to the conclusion that it wasn't worth it, especially when more power was available via after market ecu mapping etc etc.

We are now looking at the S65 for the GT3 car, BMW have gone with a stroked version for the GTS which means we can use it, people like Turner already have stroked kits for the engine but ive not found anyone who has used one yet, meeting with engine builder next week to discuss the plans.

[The Gorilla]

Hi,

I should also have added that,
the S50 B30 [E36 3.0Ltr] also has thicker
webs to the block, so the bottom end
is much more reliable than the
S50 B32 [E36 3.2 Evo.]

What does get really interesting is that
if you used a M52 engine,6 Pot Alloy Block,
so 40kgs less weight up front,
so much better handling and turn in, then
by converting it to S50 B30 M3 SPEC, as a Racer
in the States has, he is getting
304 BHP at the wheels, not Crank,
which at 155 kgs engine weight in
an E36 Shell would handle very well.

Regards,

The Gorilla.