ESE's works engine tuner

[Ocean1]

I found an article on the Porsche air cooled turbos the other day Rob. The airflow requirement per HP was rather startling to say the least.......scarey very scarey

Did it cover the standard VW fan drive belt needing to slip at higher revs?

[TZ350]

People laughed



and said it was a stupid idea



then said it wouldn't be allowed



when I talked about wanting to run the fan with an axillary motor.

But wait ... I checked and yes I can ... ... now why would I want to do that ??????

I found an article on the Porsche air cooled turbos the other day Rob. The airflow requirement per HP was rather startling to say the least.......scarey very scarey

I would love to know more about the airflow (volume) requirements per hp.

[peewee]

hi mates. this is a great site you have with alot of good info. wondering if someone could offer alittle advice. i do all my own porting but im just a amatuer really. ive read alot about the rsa125 and believe ive made some errors on my own engine. ive set all the transfer port opening at 115 atdc (130 total) and with a 7* upward angle on A,B,C. D was around 55* upward if i recall. but im thinking 7* was a mistake.

would i be better off with C around 10* and A and B more about 20* ? and open C and D at 114* then A and B at 115 atdc ? thats what im thinking might work better but im not sure. also i included what the horizontal angles look like. i was thinking to put a curve in the C ports so theyre shooting more toward the front instead of at each other. any help is great thnx . still trying to make it through 800+ pages but im learning alot

also i believe ive made some errors in the exh port but ill save them questions for later

[F5 Dave]

presumably you're talking 250 size cylinder with all those transfers?

[peewee]

500cc single. drag racing in sand. running methanol. i just think my transfer angles are all wrong so i hope somebody can help

[wobbly]

Before I tell you what to do, is this a T port and is there room to pull the C port rear wall back, and put a hook in it.
Also what's the Ex timing now, and do you need wide range power, or do you spin the tyres so much in sand that the wide gear ratios dont make much difference.

[peewee]

what do you meen by Tport ? you meen transfer port ? yes the C port is a transfer port. exh timing is 200*, opens 80atdc. aux exh ports open 3* later. i dont need wide range power because you go full throttle and dump the clutch then just start clicking gears . i can go toward the rear about 2mm more on the C port to put a hook. if i did some welding i could probly go even farther back.

[husaberg]

Did it cover the standard VW fan drive belt needing to slip at higher revs?

I posted the VW link ages ago where someone measured how efficient it is Ocean.

I would love to know more about the airflow (volume) requirements per hp.

Unfortunately Rob i can't find where the article was. i must not have bookmarked it but a quick google located this.(attached below)which is nowhere near as good.

I was emailing Rob today and he asked me if i took any pics of the Buckets at Greymouth...........er no i wish i had.
I didn't even think about it..... The RS/RGV100 sure was pretty though.
I did see this though amazing how much faster the extinguisher actually came out than it seemed at the time.

[peewee]

hey wobbly or frits or anyone else that may have advice. ive read all about the rsa125 and trying to apply some of its technology to my own cylinder. when dealing with with cylinders that have 2 extra tranfers ports like the photos above, is there any rules of thumb to follow regarding their vertical/horizontal angles ? thnx for any help

[F5 Dave]

They are n't here every day so you may have to be patient while they try grind a living

[F5 Dave]

..... The RS/RGV100 sure was pretty

Diesel' s? Yeah but he still hasn't redone the back of the tank. Sharp edges. Had bruising for days after riding it when it was MB powered.

[husaberg]

Diesel' s? Yeah but he still hasn't redone the back of the tank. Sharp edges. Had bruising for days after riding it when it was MB powered.

He mentioned you were a bit soft.........But its an interesting tank shape for sure.The bike sure has plenty of 2 stroke bling.

[wobbly]

OK so now we know its not a "Honda" T exhaust port as it has Aux Ex ports.
With the Ex up at 200* and a 3 port you should run reverse stagger.
This keeps the A port low so the front side of the Aux can also be low, but keep to a teardrop shape of the Aux to lessen the interaction with the A port exit stream.
The A port should have the roof filled to angle up at 25* with a duration around 128/130.The B and C ports higher at 130/132 and axial of around 15* on the B and 8* on the C.
The Boosts up at 55 with same timing as the B,C.
The rear wall of the C port weld and grind back as far as you can with a smooth radius hook pointing to 2/3 back from bore centre.
The Ex duct exit should be 85% of the 3 ports effective area, with an oval width the diameter of the total effective Ex port area - this then also becomes the header diameter.

[Wolfie's Girl]

Hi all,
Been a while since my last post, but I have been sequestered in the garage working on my new motor... Slowly we are getting closer to the finish... The rear of the cylinder is pretty much finished I think, but I am waiting for the crank to be pressed together with the new RGV rod installed, and a judicious application of Mallory metal.. I can't move on with the exhaust porting obviously till I have that piece of the puzzle, so that I can work out the port timings... Here are a series of pics for your perusal...
The original cylinder....



Unmasking the B transfers....


The B transfers pretty much sorted... I had a few Oppsies, but I think that I will get away with them as they are not in the ring seal area...


The new boost port...


The cases...

[Wolfie's Girl]

Also...
And lastly the NF4 ignition grafted on...




Holy Crap I can't wait....

By the way much thanks going to Mike Chandler and F5 Dave for their ongoing intelectual input... They are deffinitely the brains of the outfit!!!