bore vs stroke

[Zach Gomulka]

I disagree with the thought about end of evolution.  4 inch bores, roller cams, and beehives are all fairly new develpments for street engines.  That being said,  i really want more info on building a 4" bore motor.  Must it be done with Comp eliminators or angle flows?  I wonder if it could be done with 044's?  I don't care about power at 7k, but torque is what moves a street car.  Sounds like Jeff D is the man to talk with about such a build.

Yeah, some heads with real cooling fins would be nice.

I think I have to side with Ratto on this one, how much power do you really need in a street car? Maybe Im just not the type who is trying to set the world on fire...

[Zach Gomulka]

What an interesting post.  I will asked you some advices because I don't know what is the best to do

I'm planning to build after my 1600cc (yes only), a second engine but more exciting 
I've talking with a French specialist about building a 78*90.5 ou 94. My goal is to have an engine that could be driven on the street and have fun on the strip. I hope make time like 14sec. I was planning to use a cam as a 86B with 1.4 or so.

But, after some talks, he advised me to build a 1915cc. According to him It's a better way to have a very strong short block for less money and use this money in better heads.
He gives me  3 choices of cams. A w125, classic and multi purpose. A webcam 86B with 1.4 or a Custom made cam of 295° with 1.4. This one will give more power than a 86B at 3500rpm but less at 6000rpm. Always compromises.... I like the W125 because it is a classic choice, it was designed in 1971!! but, cam with 1.4 will give me a better power band. Exact?

Heads will be 40*35.5 or 42*37 CNC with big beef or CSP manifolds. Carbs are 44IDF. I will run stock gear box with a superdiff. I can have 8*31 or 8*35.

Is it a good combo?

 

I would use a 120 with 1.25s. Its still a pretty small motor, you dont want to over-cam it.

[louisb]

I think I have to side with Ratto on this one, how much power do you really need in a street car? Maybe Im just not the type who is trying to set the world on fire...

Someone was probably saying that when the 40 horse came out. 

It is just like what two liters are today. It has not been that long ago, 10 - 15 years, when building anything bigger than a 1835 was considered exotic and very expensive. As more and more people expressed an interest and more and more parts became off the shelf (After market big valve heads, aluminum cases, larger pistons, cheap stroker cranks & H beam rods) the price dropped significantly and now they are within the reach of almost everyone. I mean, how many builders can you now call up who have a ready made package that will make 180+ hp for around 4 grand?

I have been checking around today just to see what would be involved in building one of these big motors. Both the wasserboxer case and the CB aluminum case need significant modifications to work. The heads would be about double to triple what a set off "street" heads will run you. However, if CB made a few mods to their cases and CE heads you could have an off the shelf 3 liter for about the same price as a 2276 would cost you today. The pistons would be the only item that would probably remain expensive, but to be honest, $500 for a set of pistons is not that bad. And we all know a bigger motor makes its power at a lower rpm and with less stress to the engine.   

--louis

[Jim Ratto]

What an interesting post.  I will asked you some advices because I don't know what is the best to do

I'm planning to build after my 1600cc (yes only), a second engine but more exciting 
I've talking with a French specialist about building a 78*90.5 ou 94. My goal is to have an engine that could be driven on the street and have fun on the strip. I hope make time like 14sec. I was planning to use a cam as a 86B with 1.4 or so.

But, after some talks, he advised me to build a 1915cc. According to him It's a better way to have a very strong short block for less money and use this money in better heads.
He gives me  3 choices of cams. A w125, classic and multi purpose. A webcam 86B with 1.4 or a Custom made cam of 295° with 1.4. This one will give more power than a 86B at 3500rpm but less at 6000rpm. Always compromises.... I like the W125 because it is a classic choice, it was designed in 1971!! but, cam with 1.4 will give me a better power band. Exact?

Heads will be 40*35.5 or 42*37 CNC with big beef or CSP manifolds. Carbs are 44IDF. I will run stock gear box with a superdiff. I can have 8*31 or 8*35.

Is it a good combo?

 

Hi j-f
from experience, I would suggest the Engle K8 for your 1915cc...with 40 x 35 VW heads, with modest ports. Be sure to add a merged header and run around 9.0:1, it will run very well with your 44IDFs. I have built this motor a few times and suggested it for friends too, very fast and completely driveable under all conditions. Have fun,

[lawrence]

J-f, the french specialist seems to know what he is talking about. I built a nice 1914 for only a few thousand dollars and I spent the most money on very nice hand ported heads and 48 IDAs. My motor runs VERY strong. In fact, Jim Ratto was one person who advised me to build this motor a few years ago :

I chose to use a webcam 86b and 40x35.5 heads. Stick with the IDF as im sure they are much less tempermental than my IDAs and go with the fk8

If I could do it all again I would raise my compression ratio higher than 8.3:1, maybe 9.5:1? And maybe retard my cam a little for a tad more bottom end power. Does anyone have an idea how a web 122/125 would run in a hot street 1914. .506/.478 lift and 262 dur. at .50

Is it a good idea to use split duration cams in N/A street cars? I like the sound of a engle fk42 for a 1914. This thread is cool.

[j-f]

yes, this thread is very cool 

The French specialist really know lots of things about VW engine.

But, I like to have your opinions about building a fast little street and strip engine 

But, there is so much cam combos that is very difficult to choose one  . Stock rockers, 1.4 or 1.25, Engle w serie or FK series... Man, it's a mess.

[nicolas]

yes, this thread is very cool 

The French specialist really know lots of things about VW engine.

But, I like to have your opinions about building a fast little street and strip engine 

But, there is so much cam combos that is very difficult to choose one  . Stock rockers, 1.4 or 1.25, Engle w serie or FK series... Man, it's a mess.

it is a mess!!

but i would have opted for a 78x90 engine with either a FK8n or a W130... or a W125 i still have Jims 78 crank and was allready building a new engine with it. i was thinking of tearing the 1641 apart and clean up the heads, open the ports a little and go for the 78 x90 combo.
but just my honest opinion. why not invest in a 78 crank. you can buy a good one here on the lounge and a counterweighted 69 crank will be not much less... but i am not and expert ( i just like to think stroke and cylinders need to square up as much as possible.)
and it will need 42 dcnf berg specials on type3 manifolds or 44idf's.
but for now it will be the 'big' engine first. the other one will go into the squareback if it gets build. so i can cruise with the family to the south of france at a decent speed, fully loaded 
but as i said this is a longshot.

[Roman]

Yeah, some heads with real cooling fins would be nice.

JPM heads got even more cooling fins than stock.

[j-f]

Why a stocker rather than a strocker? Well, It's the title of this topic 
Once again, the French vw specialist advice me to keep a 69mm because I will use a stock gearbox. And the power band of a 69mm is more adapted to a stock ratio gearbox. A longer crank will have a wider power band and you will need to adapt the gearbox.
A longer crank will give more torque.

[JS]

I thought the heads, cam and such had much more to do with the power band of the engine than the stroke

[Jim Ratto]

Why a stocker rather than a strocker? Well, It's the title of this topic 
Once again, the French vw specialist advice me to keep a 69mm because I will use a stock gearbox. And the power band of a 69mm is more adapted to a stock ratio gearbox. A longer crank will have a wider power band and you will need to adapt the gearbox.
A longer crank will give more torque.

a more torquey motor will allow for a more 'forgiving' gear stack (i.e. stroker= stock gears, 69mm= close ratio)