Where does a 92.8mm stoke 5cyl crank come from?

[Vagsport]

I'm with Mihnea on this one, I used a 95.5 stroke in my S2 engine, it gave a nice fat slice of torque, I didn't rev it as high as I used to, not due to worries about it going ... BANG! but because there was so much low down torque, high revs were unessesary. With a road turbocharged motor, 9,500 RPM is way too high :eek2: That is more a route for a N/A motor. The cams required for your engine to breathe @ high RPM are unlikely to be suitable for everyday driving in real world conditions.

Siena

[mbcouple]

I have road cars, this has to be special. I am looking for a compromise. The car will be tracked, and maybe driven one day on the weekend. This will not be a daily driver. What was your opinion on the 2.5? Would you build it that way again, or would you stick with the 2.2. This motor will have custom intake, and exhast manifolds to support a large garrett. I will be using autronic management. Again, i don't want you to think i am crazy, 9500 on the road IS nuts, i just want it to be there if i ever wanted to run it that high. Basicly i want to build this motor once, and do it the best the first time.
Thanks
Hans

[mbcouple]

Would titanium connecting rods and valves with the 95mm stroke and a 82mm bore let me (A) have the displacement i want and (B) let me rev it up safely, whether i use it or not? I was going to use 4340 moly rods, but if titanium will get me there, so be it.
Hans

[mbcouple]

I forgot. I am working with an AAN motor from a 93 S4. Its real nice because it basicly just plugs into the autronic ecu.
Hans

[Mihnea]

The problem with so high revs isn't the titanium rods but the piston speeds.... I didn't do the maths yet but I hope Marco will tell us how many meters per second 9500 RPM translates to, but IMHO it's way too much...

Otherwise, I can understand you want to make something special, but you could already have 700+ HP out of a 2.2 liter engine with a suitable turbo and big enough injectors, and of course everything else modified to suit with the high internal pressures that this implies...

Mihnea

[mbcouple]

So should i use my eurovan 95mm stroker block with 144mm connecting rods and 82-82.5mm pistons with a modified cam, and extremely ported/polished head with 1mm plus sized valves or stick with the 2.2l block, and use the above mentioned parts, and get a slightly higher rev range?
Thanks
Hans

[Beppo]

Originally posted by mbcouple
So should i use my eurovan 95mm stroker block with 144mm connecting rods and 82-82.5mm pistons with a modified cam, and extremely ported/polished head with 1mm plus sized valves or stick with the 2.2l block, and use the above mentioned parts, and get a slightly higher rev range?
Thanks
Hans

There is a S2 here in sweden witch put out 809hp and 950Nm using 82mm bore with 92mm stroke´together with 144mm rods. He also drives it with a frame an the crank for higher revlimit. Racewear bolts in the entier engine. Ferrerra stainless bigger valves and extremly ported head. AEM-managemantsystem.

There is alot of stuff in that engine and I have seen it run.

It´s an absolut monster.

[Vagsport]

My 2.5L 3B was great, Mb, and yes, I would do it again, 2.2 feels quite different now.

Siena

[mbcouple]

Did you also use the eurovan block? I was curious about that. I have not measured any of the boltholes for the tensioner setup. Becaus ehte block is 15mm taller on the EV block, will it affect the tensioner mechanism? Can i use the updated tesnsioner from the 93 s4, or will i have to use the older 3b type system with the waterpump based tensioner?
Thanks
Hans

[Pisobiker]

Hans,

apart from the tremendous inertial forces a high rev forced induction engine puts over it's conrods, pistons and cranckshaft journals (forced induction engines require stronger conrods and pistons, thus heavier. Inertial forces raise proportionally to mass but with the square of speed !!), breathing will be a problem as well.

On a racing NA engine with intake and exhaust ducts dimensions optimized for max use of resonating phenomenon, 24 meters per second is already an average piston speed close to the max breathing capabilityes (which represents the reaching of sonic flow speeds somewhere in the most restrictive parts of the ducts). Of course forced induction engines don't have "resonating dimension" restrictions so that some better breathing can be achieved using larger ducts (which are not worth that much if not done accordingly with the increasing of valve diameters) and very "aggressive" cam timing, all of which will compromise low rpm tractability.

Some numbers are:

1) for 86.5mm stroke engine:

@ 7000 rpm 20.183 m/s;
@ 7500 rpm 21.066 m/s;
@ 8000 rpm 23.066 m/s;
@ 8500 rpm 24.508 m/s;
@ 9000 rpm 25.95 m/s.

2) for 95.5mm stroke engine:

@ 6500 rpm 20.691 m/s;
@ 7000 rpm 22.283 m/s;
@ 7500 rpm 23.875 m/s;
@ 8000 rpm 25.466 m/s;
@ 8500 rpm 27.058 m/s.


Numbers show an advantage of the "short" stroke vs. the "long" one, but doesn't seem that much to me.

There is another problem I see, connected with the turbocharger:

On a fairly small displacement engine like ours, to make massive torque and hp, is required high boost, well above 2 bar (3 absolute). Normally high boost compressor sides don't have a very broad flow range thus forcing to choose a big one with a surge line pretty high in the rev range. This will make the engine quite peaky.
Bigger displacement possible will allow same output with less boost, also having the boost treshold lower on the revs.

your choice on engine's behaviour you prefer.


Marco

P.S. I'm in the process of building a 95.5mm "stroker". If you will end up with it I wouldn't use stock lenght conrods (144mm). If yo do, piston compression height will be far too much (therefore needing a heavier piston) and, moreover, longer strokes prefer long rods as well.

[Pisobiker]

P.P.S Of course my P.S. statements above are correct if using the taller AEL block.

Marco

[Empo]

About the 92.8 crank, isn´t it possible that the crank is a "custom" one; built from VW crank(92.8) parts ?.....

Im also building me a stroker, but a 10 valver tough... In my opinion the 144 rods are to short. I am using longer custom ones from Verdi, with custom JE pistons. Im also using the 95.5 crank with 236mm deck height block, 16mm taller than the 3B, ABY, WR(220mm) etc blocks. There is 236mm engines fitted with 159mm c/c conrods original, maybe one way to go if you dont want to buy custom ones and building 20v, but i dont know how "strong" they are...

If anybody is looking for a 236mm block, be sure to check that the "Oil jets" under the pistons is there. Some 236mm height block´s dont have them original. Pics of my "stroker project" engine can be found at my page: www.emporace.com ("Bilder" --> "Galleri1")

[Vagsport]

The only 'tall blocks' that don't have oil spray jets under the piston are the non - turbo diesels and all 2.5 petrols. All AEL blocks have them.

Siena

[Pisobiker]

To answer some questions Hans asked me but also to hear any suggestion coming form the guys here, I'll give now some details on how I'm actually managing my "stroker" porject. Sometimes I might just "think loud" so any comment, tip, suggestion or warning will be highly appreciated.

1) Engine block and crankshaft I got come from a AEL turbodiesel engine with the 95.5 mm stroke and taller block.

2) from my mesurements over conrods and pistons I have found the following numbers:

- conrods lenght 144mm for both AEL and ADU (same as ABY/3B/AAN);
- compression height 45.7mm for AEL, 32.8 for ADU;
- piston hight over cylinder top 1.0mm for AEL, 0.0 for ADU;

This takes to 16.4mm taller cylinders for the AEL, and the need of using 11.9mm longer conrods if using ADU spec pistons.

3) If we consider ADU engine with OEM metal head gasket takes compression ratio to 9.0:1 this means if we keep ADU piston with 11.9 longer rods c.r. with the stroker will raise to 10.03:1.

I was planning to stay in the 8.5:1 c.r. range for which I'll need pistons with 11cc more dish volume on top, given all other dimensions the same.


So, to make things short:

A) I'm planning to have same dimensional spec pistons as ADU but with deeper dish on top to get the extra 11cc of volume (we already have a contact with Ross Pistons for that, thanks to "Dave-desmo888") together with 155.9mm long conrods (might have choosen even longer conrod with a lower compression height of the pistons, but would not go too extreme with the piston design). I was planning to keep the original ADU 20mm pin size, but since I have to make custom conrods I can just have best dimensioning of it as well, and rod's manufacturer suggested 22mm (so I'll need to tell Ross about this, now);

B) I was wondering which Company to ask about conrods and I would have liked to have some Carrillos (they are probably the best known worldwide) but still would try to find best quality-to-price ratio. Have contacted Pauter, who suggested for my application a nice set of 4340 conrods that, at my specs, would probably be in the 630-650g wight (just slightly heavier compared to OEM ADU ones, but I asked conrods for at least 550lb/ft torque 35 PSI boost and 650 Hp @ 7000 rpm ). I was quoted 900 U.S. $ for the set.
Having Titanium ones would reduce dramatically weight (up to 30%) thus inertial forces, but since the "stroker" wont be running extremely high rpm I thought I could avoid spending three times as much for the titanium ones ( :eek2: ).

C) Since I was planning to use RS2 cams or maybe the 7A exhaust cam, which still don't give overlap, I'm pretty sure even with the higher lift, I wont have interference problems using standard valve pockets dimensions on piston top (but Ross might cut piston top where the pockets are located to get the extra 11cc, which will just close any interference issue). If bigger diameter valves are used, It might be worth making the pockets bigger accordingly (taking then into account the change in volume to reduce from the 11cc previously computed) or making sure new piston top design doesn't give any problem.

D) As first step I'm not planning to jump to extremely high outputs and I probably will even stay with it (but you know, one can never tell.... ). Goal will probably be in the 460-480 Hp range with good low rpm tractability, so that the turbocharger will be chosen accordingly. Compared to the 2.2L the stroker should be able to spool up turbocharger some 500-600 rpm earlyer (maybe more), have slightly less peak boost (which helps when not able to find good enaugh fuel :mad: ) and still have some better responce in the low rpm when the turbo is not jet able to give it's contribution.

My car will definitly be a "road car" and this has of course addressed me to looking at this kind of setup.


Just to add something to what previously said about average piston speeds and "breathing" of engine, just think about the Honda NSX Vtech engine. It runs up to 9000 rpm in original setup, but with 72mm stroke this makes "only" 21.6 m/s .


Marco

P.S. please anyone having something to say about this, or having numbers or mesurements differnet from my ones PLEASE TELL (before I order parts )

[mbcouple]

My next question is: is the eurovan the same as the tdi block?
Thanks
Hans