Another blow thru 1600 build

[John S.]

Been collecting some parts. Not pictured is the header that I’m modifying. My bug is currently running and on the road with a 1600 I built with a mystery .419 lift cam and Weber ict’s. I want to get the 40 dell running before the turbo goes on. I do have some questions:
-Jetting pre turbo. Currently has 34 cents,145 main, 180 air, 60 idle, 50 pump, 164 emulsion
-which intake to use?
-where to pull vacuum for gauge, fuel reg and vac distributer
-do I need the heat risers on the manifold when turboed?
Thanks

[V8Nate]

I would personally use the top intake that you have in the picture. The heat risers are still needed but to have it work properly you should copy how a stock muffler would be(1 exhaust pipe coming off cyl 2 or 4 and the other exhaust pipe routed down to the collector) as far as your vacuum port you can tap the cyl 3+4 end casting and run your vacuum off of that. What vacuum advance cup are you planning on using and what distributor? As far as jetting goes you need a wideband o2 gauge to get it right I'm sure someone on here can get you in the ball park but every motor is different

[Clonebug]

When I ran blow through with my 34 pict I never used manifold heat. It never was an issue since the turbo will always feed the engine air that is warmer than ambient.
At 60-80 degrees ambient I see a 20 degree temp rise through the turbo just cruising once the engine is warmed up.

[John S.]

The top manifold has larger diameter pipe. I do have the heat rise pipes.
I planned on using a DVA distributer. And only use the normal side. It has 22-25 cent. advance and advances with vacuum another 5-8. In theory, I think it should work.
I have a machine in forged piston 1679 on the drawing board.

And everything in the pic, I got for free or really cheap. I do have to buy a BOV.

[John S.]

That turbo is off a 1982 2.0 Saab with 137hp. I've had it since the late 90's. God time flies.

[ct937]

As a guy with a blow through 40mm Dell on a 1600 I wish I could help with the jetting but mine came pretty well tuned so I never had it apart.

I’d skip the heat risers for the reasons Clonebug stated.

If your dizzy adds 22-25 degrees mechanic advance then wouldn’t that leave your base timing would end up at 0 btdc? Unless I misunderstood?

I referenced my boost gauge and fuel pressure regulator off of the carb hat. My blowoff sees manifold pressure through the hole circled in your photo. I took a photo of mine in case it helps. (For whatever reason the forum flipped the photos..)

890CD8F8-F601-473D-9091-5158071E3CAD.jpeg

41ABC34D-C610-4E51-9152-184966B68FA6.jpeg

835391B1-468A-4A47-8E5E-E2DF339416B9.jpeg

[John S.]

Without playing with the distributer, yet. I’m guessing static would be zero and I would advance to something at idle speed.

[Clonebug]

I do have to buy a BOV.

Here is what I use....it's proven and it's cheap.
I've had mine since the beginning in 2011 and it's held up to 25 lbs. boost.

https://www.ebay.com/itm/94-05-00-98-97 ... SwXk9carPg

[John S.]

Does that BOV use a rubber grommet or something?

[buguy]

I just installed one of those on mine yesterday. I had to weld a 1" tube to my intake and use a 1" silicone coupler to connect the two together.
You can see it at the bottom of my thread.
viewtopic.php?t=149802&start=2400

[Clonebug]

Technically it’s called a bypass valve ... not a bov.
You will need to put a filter on the outlet due to vacuum situations holding it open like light cruise.
I just used one of the V-8 valve cover filters and a short piece of one inch hose. You could also plumb it back into the intake before the turbo if you have the room.
It’s a tough little guy and even though it’s plastic it’s held up well for me.
I’m all about the cheap and not the bling though....

[buguy]

Interesting. I have never heard of having to do that before.

[Clonebug]

Interesting. I have never heard of having to do that before.

Once you get yours running check it.....at higher vacuum like idle and cruise it is open and could suck in unfiltered air.

Aftermarket BOV's have a stronger spring inside and usually stay closed.

It's not a really big deal to me since those Valve Cover Filters are cheap and fit on easily......like I said...not the bling or the cost like TurboSmart or others like that.
It still makes a loud Whooosh especially at 20-25 lbs.....

[buguy]

That wouldn't be good! Mines right out in the dirt!
I am a bit surprised the filter doesn't slow down the out coming air though. You've been running it a long time, so that's tested well enough for me.

[John S.]

The header that I’m going to use. I picked it because of the pushed back collector. The turbo will be in the engine compartment.