Higher Revs

[cormac163]

i have decided that i am going to build myself t4 engine for my turbo so i will get much more time out of it. But before i start with the engine i want to know what the best way of getting the most revs are. I am only looking at max 2.1l and i have little knowlege of head sizes for a type 4. R there any good rebuild books on the subject mainly the car is a daily driver which i will use for the odd track day. I do mostly motorway driving but i have 12 miles of windy country roads to get to it so i like to spin up quickly. whatcha reckon on building from scrtch or buying on old box and sorting it out myself.
thanks

[craazy Cooter]

You want a light car with a light rotating mass. Lightened flywheel, aluminum rods, fully balanced rotating assembly balanced with the clutch. Short stroke, big bore engine. Strong studs and rod bolts. Expensive heads and a nice header.

[Supa Ninja]

The cool thing with running a turbo is you can cut a corner on the heads, by not "needing" all that port and polishing since it is forced induction. Turbo pressure and cam profile determine how much fuel/air mixture gets to the combustion chamber, not just the VE.
On a revver keep in mind that points can float over 6000 rpm's which could lead to missfiring, electronic ignition cures that. Valves may float also.
One thing that I'm finding out is on sport bikes (very high revvers) some guys epoxy their intake ports to cause a venturi effect and increase midrange. I don't think that would help a VW cause we won't ever see those kind of rpm's. But VW did put smaller valves on their 2.0L bus motors to increase the bottom end torque. I just have been trying to figure out how to use some of the technology from my street bike and maybe make it work on a VW. 750cc, 126 hp, 80 ft lbs 12,500 redline, 4 38mm carbs, lasts 60K+ miles. I do know I want that kind of acceleration from my bug but that will take a little bit of work. Turbo will most likely be the key.

Nick

[boygenius]

Originally Posted by Supa Ninja

I just have been trying to figure out how to use some of the technology from my street bike and maybe make it work on a VW. 750cc, 126 hp, 80 ft lbs 12,500 redline, 4 38mm carbs, lasts 60K+ miles. I do know I want that kind of acceleration from my bug but that will take a little bit of work. Turbo will most likely be the key.

Nick

Where did you get your HP figures from. They seem a little high unless they are crank HP numbers.

Should be able to get 100K miles out of a "PROPERLY" maintained bike.

[Supa Ninja]

That is the crank #'s, it's about a 20% loss to the wheel. I want to dyno it soon. I think it depends on maintence and how hard it's ridin for life span, and I go through VW engines like a baby goes through diapers so I'll be happy with 60,000 out of the bike's engine. Also on bikes they can gain a couple of horses from certain spark plugs, every little bit helps. Oh ya my bike is not 750cc's but 748cc's.

Nick

[boygenius]

Originally Posted by Supa Ninja

That is the crank #'s, it's about a 20% loss to the wheel. I want to dyno it soon. I think it depends on maintence and how hard it's ridin for life span, and I go through VW engines like a baby goes through diapers so I'll be happy with 60,000 out of the bike's engine. Also on bikes they can gain a couple of horses from certain spark plugs, every little bit helps. Oh ya my bike is not 750cc's but 748cc's.

Nick

Well since it is crank HP it makes sence.

What spark plugs are you talking about. Don't wast your money on some iridium plugs since you have to change them every year anyway.

[NO_H2O]

Dynamic Balance to better than 0.02 oz/inch.

[Supa Ninja]

BG, guys run the NGK CR9EK instead of the recommended CR9E's and they have been getting 1-2 more horses. If I only get one horse from 25$ worth of plugs then thats worth it to me.