VR6 conversion...it has begun :)

[yousaidpoo]

how do you think a 1.8turbo would stack up against the vr6?

[Alfred1]

The 1.8T is an award winning engine too. I think the latest version makes 180hp versus 175 for the 12 valve VR6. I may have a deal to buy a VR6, I'm waiting for the guy's phone call now.

[BigD9146gt]

I really like the idea of this motor... keeping it in the VW family (not really common these days with the chevy being so popular).

My only note that i'd like to add is that keep in mind HP upgrades arn't as cheap as some of you might think. 600+ hp would be awesome, and when a $3K budget... but remember that the 901 box can only take 230hp on a dayly basis, being conservative to 1st and 2nd gears as you launch.

The 915+wevo setup will run about $3K-$4K all said and done, and will take around 500hp?, then for the mad man, the G50, and a time consuming cable system to boot.

Just a thought to keep in mind for all those seeking more power.

Awesome project, keep the pics comming!

[yousaidpoo]

yea, i would be leaving the motor more or less stock. 175 horsepower in a roughly 2000 pound car will get you down the road pretty quick. i think i would kill myself with 600hp on street tires. especially since i like to go see just how far a car will go, occasionally at inoppourtune moments...

not that i would mind 600hp or anything...

the things about the turbo though, are:
A)turbo lag. it sucks
B)more stuff to break
C)correct me if im wrong, but wouldnt a trubo'd engine run hotter to begin with, and since cooling is going to be a bit of an issue, wouldnt that be bad...

[Alfred1]

The 1.8T has very little turbo lag. 600 hp in 914 would probably tear the chassis apart.

[Jason Porter]

Originally posted by Alfred1
The 1.8T has very little turbo lag. 600 hp in 914 would probably tear the chassis apart.

Actually, HP wouldn't be much of an issue, but more than 350-400 ft.-lbs. of torque will start breaking chassis components.

[914GT]

But 600 HP would be 788 ft-lbs of torque at 4000 rpm and 525 ft-lbs at 6000 rpm given that horsepower and torque are related...

[Alfred1]

Yup, hp = (torque x rpm)/5252 so saying, for example, that an engine has lots of low-end torque compared to another engine is the same as saying that it has lots of low-end hp compared to the other engine. Diesels have lots of low-end hp.

[Dave at Pelican Parts]

Originally posted by 914GT
But 600 HP would be 788 ft-lbs of torque at 4000 rpm and 525 ft-lbs at 6000 rpm given that horsepower and torque are related...

That would only be true if whatever engine you're talking about made 600 HP all the way from 4000 RPM up through 6000 RPM. Usually the numbers quoted are "peak" numbers, and to get high numbers you usually wind up with a pretty "peaky" motor--one that makes much less HP at anything less than very high revs. (Think Honda S2000...)

--DD

[Alfred1]

Well, I have a tentative deal to buy a complete engine and tranny from a '99 Golf VR6 for $2500 Cdn. Time (and money for adapters, custom exhaust etc.) will tell if it's a good deal.

[Jason Porter]

Originally posted by Dave at Pelican Parts
That would only be true if whatever engine you're talking about made 600 HP all the way from 4000 RPM up through 6000 RPM. Usually the numbers quoted are "peak" numbers, and to get high numbers you usually wind up with a pretty "peaky" motor--one that makes much less HP at anything less than very high revs. (Think Honda S2000...)

--DD

Thank you Dave. HP and torque don't have to be related in any way, except that if an engine makes Y amount of HP, that it makes X amount of torque. The 2 are never proportional as far as a set formula goes.

Take a 69 Riviera, 360 HP, 475 ft-lbs torque.

[914GT]

My only point was that 600HP is going to result in a certain amount of torque someplace in the rpm range, and that torque will exceed 350 ft-lbs. They are not totally independent parameters but I understand what you're saying.

[Alfred1]

If the turbocharged VR6 produced its 600hp at 7000 rpm (I personally doubt that the engine's redline is that high), then that would indicate that it produces 450 lb*ft of torque at 7000 rpm. I understand that both engine and chassis dynos measure torque and then calculate the corresponding hp from the torque and rpm.

[Dave at Pelican Parts]

Actually, I think that the inertia-type dynos (where the car/engine spins up a weight of a known mass) measure HP directly, and "back-calculate" torque from that.

Brake-type dynos do measure torque directly.

--DD

[lapuwali]

Torque is basically related to engine size and breathing capacity. HP is related to torque plus the ability to continue to breathe at high revs. For example, a 600cc bike engine may make about 100hp at peak (they do these days), but only have about 40ft/lbs of torque. The torque figure hasn't changed much in the past 20 years, but the HP peak has doubled over that same time frame, as the manufacturers pushed redlines up from 8000rpm to 14,000rpm.

For another example, the 2.4 911 engines came in three versions, distinguished (for our purposes), only by the cam and port sizes. The T made 140hp, the E make 165hp, and the S 190hp, but all made 145ft/lbs of torque.

The most extreme example today would be the F1 engines, which all make something north of 900hp, but also only make about 200ft/lbs of torque. Revving to 19,000rpm will do that.

[Alfred1]

Dave,

If the moment of inertia (rotational inertia) of an object like a chassis dyno roller is known and if you know the angular velocity and acceleration of the roller, then you can calculate the power causing the acceleration. This is how I thought chassis dynos work (and maybe some do, I dunno) but I saw an episode of Popular Hotrodding Magazine on tv where they talked about chassis dynos and how they measure hp. According to the show, the chassis dyno measures the torque at the car's drive wheels and then calculates the hp from this value.

Here are a couple of pages from the Desktop Dynos book where they talk about how modern engine dynos calculate hp. They measure the torque that an engine produces and then calculate the hp from this info.

[lapuwali]

I, for one, would not use any comment from a show like Popular Hotrodding as definitive on any subject. An offhand comment would be esp. suspect. 90% of these guys have no idea of what they're talking about, they're just talking heads. A great many otherwise very good craftsmen and mechanics don't really understand the theory behind what they do, and esp. don't understand the subtle differences in terminology. All too many people who should know better think torque simply refers to low-end power.

Roller type inertia dynos measure HP, and derive torque. Brake dynos do the opposite. The excerpt from your book doesn't even address the difference.

[Alfred1]

It was one of their tech segment type pieces with computer graphics and an announcer guy explaining the process.

-----

It was probably in this episode http://www.phrtv.com/2001Season/219805/index.asp .

[mike mueller]

the exhaust should be one of the easiest parts of the conversion, there is a ton of room on that side of the motor...for now, I am just going to use the factory iron exhaust manifolds and bolt something up to those.........


the 1.8t is a great motor, one problem is the price, due to them being popular for VW watercooled conversions, the price is still up there, besides, I like the idea of the six better.....there is a guy in Hayward, CA doing a 1.8T conversion right now, he is using the transaxle from the Audi, which is almost the same as the Boxster transmission......

if I had to the money to spend on some of those high-end turbo kits or supercharger kits, I'd rather just go with an air-cooled 3.6 form a 964 or 993

[Alfred1]

I bet the six sounds better than the four. Are you using the 901 transmission?