2276 Draw through 'glass buggy. It's finally happening!

[slayer61]

My apologies if these questions sound remedial, or basic, but I have limited hot motor, first hand knowledge, and this IS my first attempt at a turbo, and I've already experienced a motor failure due to detonation. Your help and assistance is very much appreciated.

[BugUgly]

Keep asking 'em! (I'm learning vicariously.)

[Alexander_Monday]

The longer the duration of the camshaft the less effective compression you will have.

And that holds true even under boost? According to the cam card with my W125 cam, it has 262 degrees of duration at 0.050" of lift?

ETA 46 degrees of crankshaft rotation overlap


Yes... and a 471 is a very small blower

Yes, NA or boost your dynamic and effective compression are affected by duration.
To be more specific, it is the intake valve closing (which usually moves to later with more duration but lobe separation and cam advance will have a small say so) that affects effective compression.
Here is an effective compression ratio calculator that has an explanation.
http://www.wallaceracing.com/eff-cr.php
With the 2387 I will have a static of 9.2 and according to that calculator I will have an effective of 6.2 but with 15# of boost an effective of 13.5 which should be safe with E85 and intercooling.

But as I said apples to oranges, so you need input from those that run pump gas and a turbo to know what is safe.

[Piledriver]

And that's about a 290 degree cam, should pull to 7-7.5k NA with decent heads.
10.5:1 on premium given 10 PSI boost, maybe much more with some water spray.

A well known engine builder specd me a cam for a lowish boost T4, about 240 degrees @.050 and 11:1 CR, pump premium low boost and e85 for not so low boost.

Without an intercooler (an impossibility with draw through carb, but you can use it with an intercooler as a TB for injectors at the ports...)...water or water & meth spray is the only way to run much more boost due to high IAT.
(or e85 which gives significant intercooling effect injected at the draw through, has been done)

Have seen a draw through Weber setup with a hidden charge cooler (and port injection) looked old school but can do 30 PSI...The fuel line to the carb was for show.

Mind, I have studied the hell out of it but have not gone there yet, too many projects. Hopefully this winter...
My e85 dreams were greatly damaged when they changed ~all the e85 pumps around here with E15 that absolutely no one buys.

[slayer61]

Thanks guys. I understand that and intercooler is out of the question, given a draw through turbo. I have considered water/meth injection for later on though. I think I was playing with numbers on the Wallace racing calculator last night. Very interesting. Thank you both again

[slayer61]

Alright guys, it's question time again! Copper cylinder spacers, or copper head gaskets, whatever it is that you call them... anneàl them first, or right out of the package?

[Piledriver]

The t1 folk seem to use the copper head gaskets.
T4 use cylinder base with maybe copper-kote brushed on at head for bit of oil seal.(have used on base as well)
I'd use the copperkote either way.

I put a spray coat of copperkote on the echambers of my vanagon just to see what would happen.
It went 65k miles without damage.
I have no idea if it helped anything but the chambers were spotless. the only place it burned off was on the exhaust valves.

[slayer61]

Interesting... I have copper spray and silicone, but it sounds like you have it in a brush able type?

[slayer61]

Greg Tims told me he has a 6-8 week lead time for his heads, and we are at week 6! Any time now, and it'll be GAME ON!

[Piledriver]

Interesting... I have copper spray and silicone, but it sounds like you have it in a brush able type?

Spray some in the cap or aluminum foil baking cup (DIY easy) , allow to evaporate a bit. Much better control with a paintbrush.

[slayer61]

Greg Tims told me he has a 6-8 week lead time for his heads, and we are at week 6! Any time now, and it'll be GAME ON!

The Tims heads are out for delivery today! Huzzah!

[woodsbuggy1]

Pics please

[slayer61]

Pics please

The heads and push rod tubes are installed, and push rods have been ordered. I used my patented push rod installation tool to ease the task.



With the heads on, I could start mocking up the new RLR carbon sealed turbo and associated plumbing.

I'm liking the way it looks so far!







More to come, between holidays honey do's and regular domestic chores

[slayer61]

I forgot to mention how beautiful Greg's heads are!

[Piledriver]

Nice...Semi hemi from the looks and CCs... I had JE make me some domes to match the semi-hemi cut chamber on some T4 heads... Its usually a cone shape rather than a radii, so easy for them to do if you ever want to add some squish.