PROJECT , TURBO ( SITE )

[Site]

I want to plan a blow-through boost setup for my 40 DCOEs (once the suckers are in - having the intake made now). From what I understand, DCOEs are sealed and can take moderate boost. I also have some pics of a "turbo hat" made for DCOEs (See Pic Below). Most who boost DCOEs do it with one 45mm carb, not twin 40s. I want to do it with twin 40s. I'm new with this, but I have time and $ to put toward it.

Things I wanna think through - supercharger or turbocharger? (Remember, the sidedrafts open toward the windshield.)
Fuel management - no Funstick, I don't want EFI .
Exhaust considerations - what size piping, etc.
Compression - new pistons, Wiseco, JE, etc.
Cam regrind specs.
Consider that I will want to put in nitrous (fogger-type).

You won't be wasting your time helping me think through this. This is something I plan to carry through with. Thanks!

[Site]

Another pic of the turbo hat:

[Site]

And another:

[Sean]

i thnk youve got a long road ahead of you for sure. manageing the fuel is gonne be tough but spark it another issue. i got some help for that.

[Site]

A long term process for this is okay for me. I'm in no rush, but I am determined to do it. In you opinion, is this do-able, funstick?

[Sean]

yeah but yr gonnaneed to manage the spark

[Site]

After some reading, seems like I'm gonna need to build a box around the carbs. This seems like best route to take. My carbs have plastic floats, so I'll either need to get brass floats or maybe fill mine with foam to keep them from being crushed.

As far as fuel enrichment goes, what do you think about fitting fuel injectors in the intake runners (like a direct port fogger system) that open up at boost? I'll need some kind of boost-sensing controller for the injectors. That way I can keep my carbs with normal jetting for off-track driving.

I guess I need to take back the "no EFI" comment I made earlier, maybe.

I've thought about a belt driven fuel pump, but I would have to jet the carbs for boost then and they will run way rich at low RPMs.

[Site]

Here's a really nice pic of a single 45DCOE enclusure in a lotus (came stock like this!). I know it's for a single sidedraft, and I'm dealing with twin, but you get the idea.

[Site]

Anyone know where I can get an adjustable FPR with an atmospheric (not boost) pressure reference? Possibility - I could plumb it into the carb enclosure, set the FPR to start at 3.5 psi, then it would adjust according to the pressure the carb views as "atmospheric", since they're enclosed. This and a slightly updgraded fuel pump theoretically could solve the fuel management issue.

[Site]

Would something like this be sufficient to produce enough forced air to fill and boost an enclosure? Someone with turbo knowledge help me out here - would I need this whole setup?

http://cgi.ebay.com/ebaymotors/ws/eB...tem=1856471906

[Site]

Found this post way deep in an forum archive online. I emailed the originator of the post (it's from 1995) and my message got returned with fatal errors - oh well, at least I have his post.

A blow thru turbo installation is next to simple with mikuni/weber side drafts. An "air box" mating with both carb faces, allowing boost to barrels and fuel bowl vent is the start. Keeping air cleaners inside helps to reduce turbo turbulence. Apply your boost to this enclosure. Fuel supply must be enhanced to accomodate the boost however. You need a pump with sufficient volume, and pressure to match original requirement plus boost pressure. Use an adjustable fuel pressure regulator, with an atmospheric pressure reference vent that you can plumb into the air box, so fuel pressure will automatically be regulated to the set value, compensating for varying boost pressures. Holley offers such a regulator. (that is, if set for 3psi, pressure will be regulated to 3psi above boost pressure). Jet sizes for the carbs can stay the same, although slightly richer jetting can be easier on the turbo. The webers, I'm told can handle up to 20psi positive boost, without leakage around the throttle shaft, or gaskets. Im sure the mikuni's are capable of the same. They're a fine carb of almost identical design. I have a picture of a quad4 oldsmobile engine done this way, I'll try to find and scan it. It made 700 HP from 2.3L! Word is, the blow thru set up on sidedrafts offers excellent throttle response, since the throttles are a few inches from the valves. Beats the crap out of the stock EFI lag. I don't need time to drink a cup of coffee, between pressing the accelerator, and leaving at a green light...

If this guy's right, then I won't need to enclose the carbs. Instead, I'd be able to use a "turbo hat" type box as is pictured above.

I've also found this, which I think will help with the fuel management problem if it can be set to regulate fuel pressure at a low enough psi. I've emailed the company to ask:
http://www.magnumforceracing.com/mag... or Regulators

Or this, since I'm not sure that the above regulator references boost:
http://216.242.145.16/products/product.phtml?p=20

[Sean]

might a irecomend a fuel pump. any of the gm truck tbi pumps will fit in the stock hanger with soem trimming and they tend to run at a mzx of about 20 psi. with a good regulator this should pose no problem with a sufficient reutrn line.

[Site]

Thanks for the info, funstick! One thing that I saw as a roadblock is the cost of the aftermarket performance electric fuel pumps for carb setups. Most are nearly $300! Again, your advice is invaluable - thanks!

[Site]

Just got off the phone with Jeff from www.mazdaracing.com. He says they have single DCOE turbo setups using the above pictured "turbo hat" for Mazda racecars that run 25 psi boost. He told me that they "turbo-prep" the Webers using their own special methods and that turbo-prepped DCOEs can handle 30+ psi of boost. I'm presuming this turbo-prep might include high strength gaskets and other sealing techniques. He said if I sent in my whole sidedrafts/manifold setup they would custom machine me a single "turbo hat" that feeds both carbs.

I'm thinking that sending it off to them will be way expensive. A single turbo hat for one DCOE goes for $380 on their site - a custom job would surely be more than that.

The more I think through this, the more I believe that enclosing the carbs in an airtight box (keeping the pressure inside the carbs the same as the pressure outside) is the best option. I can't help but think that consistent boost pressure inside the DCOEs will mean frequent rebuilds and leak risks. I enjoy rebuilding carbs as much as the next guy, but this car will be a daily driver and will get lots of use. I'm not up for doing a "carb check" every time I pull into the garage!

I'm going to look into having the machine shop that did my manifold do an enclosure box for me. Or I may do some experimenting with other heat resistant, lightweight materials. It would be very tight to use some kind of clear, acrylic type material for the enclosure. Then I'd still be able to check out the carbs without removing stuff from the engine.

Update - I'm hoping to start the car up with the DCOEs installed tonight!

[3rdGenFanatic]

Is turbo possible for the Weber 32/36?

[Site]

I don't see why not - A20A1 has forced induction through a hood scoop on his 32/36. It probably adds 1-2 psi boost. If you want strong boost on the 32/36, I'll bet you'll have to enclose it in an airtight box.

[3rdGenFanatic]

Thanks site How many PSI boost will I be safe with? Maybe around 5?

[Site]

I've looked around for an answer to how much boost the Weber D series carb can take, and I'm finding nothing. Maybe it will be up to you to test it out! There's not a lot you could permanently damage by experimenting with it.

[3rdGenFanatic]

Sounds fun.. I'll give you guys very thurough results.

[Site]

This project is coming along well. I've got a lot of part #s and a lot of ideas, but not a lot of money to spend - LOL. Yet . . . but tax return time is soon

I'm approaching this from the perspective of setting up a small-displacement drag engine. There's some good resources out there (websites and catalogs) for this.

I think I have the fuel supply close to do-able. I want to use an Aeromotive Street Rod pump or A1000 fuel pump to flow the fuel. To regulate fuel pressure I'm choosing between an Aeromotive Carb Bypass regulator with boost ref or a MagnaFlow Fuel Control Unit with boost ref. Both companies carry a model with 2 port output so each carb will get a feed.

I'll have to put in either LXi fuel lines (so I get a return line) or custom something.

A big deal gets made about spark control. I'm not sure why, but I don't want to blow this off. I don't know what the problem is with throwing in a MSD Programmable Digital 7 (click to read up), but some people seem to think that spark control will be a much bigger deal than anything else in this project.

I'm totally open to ideas on ignition.

[PhydeauX]

Wait untill they finish developing this, http://www.bgsoflex.com/mjl/mjl_edis.html
Unless sean comes up with a stand alone dis unit before that.

andy

[2old_honda]

hey check this out- http://cgi.ebay.com/ebaymotors/ws/eB...&category=6755

[Site]

Behold the picture of a Toyota 22R blow-through turbo setup with Weber DCOE 45s!

LOL 2old, I think I posted this right after you posted the link above. That setup is amazing! I've never seen anything like it. It's beautiful :lol

I'm trying to find out where he got the airboxes that bolt onto the carbs.

[2old_honda]

yeah, it really is beautiful! If only I had a toyota truck to put it on. lol

[1989 DX R]

Old Celicas like the 1986 and previous had the 22R and RE motors if I'm not mistaken.