Tom's B6 Build Thread

[Advancedynamix]

Casper hasn't run in at least 4 years. I saw the car 2 or 3 years ago in Apache Junction at a house Brett was renting. The car is pretty rough now, but can be revived. I'll be sure to post a thread about Casper if and when I can get the car.

[TominMO]

Casper hasn't run in at least 4 years. I saw the car 2 or 3 years ago in Apache Junction at a house Brett was renting. The car is pretty rough now, but can be revived. I'll be sure to post a thread about Casper if and when I can get the car.

So he bought it, then let it fall apart? Sad.

[TominMO]

MPG run, Matt Dickmeyer-built B6 head + header

Oh man, you're not gonna believe this.....

This morning I went out and performed another of my MPG runs. Same course and methods I always use. Very carefully fill the tank before and after, drive @ 60 MPH for the whole course. Perfect weather: no wind, clear day, temps in the 70s.

Vehicle variables: I had the radio on, one rear window open for better venting, and smaller/lighter tires than before. On these same wheels, previously I had used 185/60-14s; now I have 165/55-14s. Previous motor was a stock 8v B6, with a burned #1 exhaust valve (I think it was always that way--we didn't pull the head when we stuck the motor in the car). Stock B6 manifold and downpipe, connected to a stock Festy B-pipe and muffler. With that setup, twice I recorded 41.9 MPG on the same course I did today.

With the taller tires, RPM @ 60 = 2400. With these, RPM @ 60 = ~2650. So right there alone I expected a mileage hit. Not to mention the far better breathing of the current motor setup.

I corrected the odometer on the same 20-mile stretch I always use, and got the speed right by timing the distance between mileage markers. I drove at an indicated 62.5-63.0 MPH, as much as possible.

I noticed that the gas gauge was going down really slowly for the gas mileage I was expecting to see. Based on the Dickmeyer B3 motor, which got 48.0 MPG with 155/80-13s, I was expecting to see about a 10% decrease or possibly more, say 38 MPG, with this motor over the stock B6. (My stock-B3 test gave me 52.5 MPG). BTW all my tests in this car have been done with the same Festy 5-speed tranny.

So I pulled into the gas station, noting mileage on the tripmeter and making the odometer adjustment (+2.6 miles), and got exactly 93.0 miles. Filled up the tank--in fact slightly over-filled it, darn it. It took 1.97 gallons. Round up to 2.0.

That means that this B6, which I expect to give really nice numbers tmw on the dyno (135 WHP or better), got 46.5 MPG. About 10% better than the stock motor! So an 8v B6 motor that will crush a stock BP (~110-115 WHP) is only getting 6.0 MPG worse than a stock B3. That means that over a long period of time, the motor work will theoretically pay for itself! I say theoretically because we all know there's no way I can avoid sticking my foot in it on a regular basis.....:-)

One possible conclusion: lighter, skinnier tires trump 10% higher RPM.
Another: the higher efficiency of this motor meant my right foot did not have to be so close to the floor.
Plus, the stock head might have given better MPG numbers if it was in better condition.

[sketchman]

That is great.

I wouldn't count out still getting low 40s regularly. What's the cost so far just in parts + paid work?

[TominMO]

That is great.

I wouldn't count out still getting low 40s regularly. What's the cost so far just in parts + paid work?

If you're talking about what I paid Matt for the head work + modding/repairing/blasting the header, it came to $1500 parts and labor. I don't count the basic cost of the header, because I had already bought that when I bought his shop car.

Dyno numbers up tmw afternoon!

[sketchman]

Sweet!

[red90festyonair]

That is some good information posted above! Good job Tom.

[TominMO]

That is some good information posted above! Good job Tom.

Thanks.

Also note that if you want Matt to duplicate this on a B3 or B6, he will need the manually-adjustable rocker setup from a carby B3 or a gen1 B6. Has to do with valve cover clearance issues I believe, with the taller cam lobes.

[TominMO]

Mine's making plenty of torque down low, with this cam profile. Matt thinks this head makes more HP at 2000 RPM than stock peak power @ 5500 or so. His B3 was like that. We'll know more Friday.

Correction here--more torque @ 2000 than stock peak torque.

Does anyone have a dyno readout for a stock BP handy? I'd be curious to see the torque figures especially.

The cam on this motor is biased toward a wide power band, not peak HP, so frankly I don't expect insane WHP numbers like his measurement of 155 CFM would indicate. Not to mention the stock intake and (probably) smaller-than-optimal header runners. I'd be happy with 135 for sure. But I'm pretty sure it's gonna read as torquier than a BP.

[TominMO]

Here's some good Festy dyno porn.....

[Flyin4stroke]

[emoji97][emoji97][emoji97]

[TominMO]

[emoji97][emoji97][emoji97]

Is that what I think it is?!

[bhearts]

O nooo! Lol

Sent from my SM-G900V using Tapatalk

[bhearts]

MPG run, Matt Dickmeyer-built B6 head + header

Oh man, you're not gonna believe this.....

This morning I went out and performed another of my MPG runs. Same course and methods I always use. Very carefully fill the tank before and after, drive @ 60 MPH for the whole course. Perfect weather: no wind, clear day, temps in the 70s.

Vehicle variables: I had the radio on, one rear window open for better venting, and smaller/lighter tires than before. On these same wheels, previously I had used 185/60-14s; now I have 165/55-14s. Previous motor was a stock 8v B6, with a burned #1 exhaust valve (I think it was always that way--we didn't pull the head when we stuck the motor in the car). Stock B6 manifold and downpipe, connected to a stock Festy B-pipe and muffler. With that setup, twice I recorded 41.9 MPG on the same course I did today.

With the taller tires, RPM @ 60 = 2400. With these, RPM @ 60 = ~2650. So right there alone I expected a mileage hit. Not to mention the far better breathing of the current motor setup.

I corrected the odometer on the same 20-mile stretch I always use, and got the speed right by timing the distance between mileage markers. I drove at an indicated 62.5-63.0 MPH, as much as possible.

I noticed that the gas gauge was going down really slowly for the gas mileage I was expecting to see. Based on the Dickmeyer B3 motor, which got 48.0 MPG with 155/80-13s, I was expecting to see about a 10% decrease or possibly more, say 38 MPG, with this motor over the stock B6. (My stock-B3 test gave me 52.5 MPG). BTW all my tests in this car have been done with the same Festy 5-speed tranny.

So I pulled into the gas station, noting mileage on the tripmeter and making the odometer adjustment (+2.6 miles), and got exactly 93.0 miles. Filled up the tank--in fact slightly over-filled it, darn it. It took 1.97 gallons. Round up to 2.0.

That means that this B6, which I expect to give really nice numbers tmw on the dyno (135 WHP or better), got 46.5 MPG. About 10% better than the stock motor! So an 8v B6 motor that will crush a stock BP (~110-115 WHP) is only getting 6.0 MPG worse than a stock B3. That means that over a long period of time, the motor work will theoretically pay for itself! I say theoretically because we all know there's no way I can avoid sticking my foot in it on a regular basis.....:-)

One possible conclusion: lighter, skinnier tires trump 10% higher RPM.
Another: the higher efficiency of this motor meant my right foot did not have to be so close to the floor.
Plus, the stock head might have given better MPG numbers if it was in better condition.

You never stated if your vacuum at cruise numbers changed

Sent from my SM-G900V using Tapatalk

[TominMO]

You never stated if your vacuum at cruise numbers changed

Because I didn't measure it. Never do.