Webcon Retroject 38/38 TBI

[Mark Sucher]

Has anyone replaced a conventional carb 32/36, 38/38 with a Retroject 38/38 TBI?

https://www.webcon.co.uk/products/15299-retroject-3838-throttle-body/

 

I'm currently running a Weber 38/38 in my '71 and am curious about this.

Looks interesting, but don't know anything more than what's on their site.

 

Thanks in advance for any comments.

[Son of Marty]

618.60 is pretty steep for just the throttle body, but if you have the bread to experiment it would be worth finding out how it works, but IMO throttle body injection is only a bridge between carbs and individual cylinder injection and for what the projected cost of finishing this set up you could get a straight efi set up.

[xr4tic]

Some details in the link below.

 

As to the price, you're paying for convenience, it's the closest thing to bolt-on for our cars, but it still requires some modifications.

 

[Mark Sucher]

You're both right. It would be close to an ITB, and what's being offered is convenience.

Clearly more clear thinking on my part is needed here.

 

Thanks for seeing things that I didn't.

[2002iii]

About $620 for the throttle body, but you still need an ecu, programming/tuning and various small parts.

 

In the post above I asked about the setup used. He said they had to modify the intake manifold and get an adapter made for the air filter housing. They chose the ECUmaster EMU, which costs $900.They also used the recommend EFI Fuel pump / Swirl pot assembly, which costs about $380. Then they had to have it tuned, and ended up with 110hp and 133ft lbs.

 

So that's $1900 in parts, not counting small parts, fabrication, installation and tuning. So assuming you can do the fabrication and installation yourself, add atleast $200 for small parts and atleast $500 for tuning. That's $2600 and that's best case scenario.

 

It would probably be easier and a lot cheaper to convert to the e30 m10 318i fuel injection system.

 

Or use some combination of stock BMW and aftermarket fuel injection. There are lots of options out there, from mild to wild and all the way inbetween. There are some packages that claim to be bolt on and/or plug and play, but we all know how that works lol.

 

If you're going to spend the money and do it right you should do lots of research and decide what works best for you and your budget.

 

I think if it was me I would go for individual throttle bodies with a Megasquirt and individual coils so I could try tuning it myself with help from forums, late e30 single high pressure in tank fuel pump and small parts from various sources.

Edited April 7, 2021 by 2002iii

[Mark Sucher]

Sounds like a great over – the – winter project. Should give me enough time to research thoroughly and line up any additional resources I need for the things I cannot do myself.

 

Again, I appreciate your guide to better alternatives. Thanks, and take care

[TobyB]

Kinda like the 38/38- drop it on a stock engine, get stock results.

 

t

[Mark Sucher]

True, but my engine has 9.5 cr, 292 cam, larger valves, headers, 2" exhaust, and the 38/38. A nice streetable motor. Am just curious about the TBI with a computer and wideband O2. Would it make it more tractable? Don't know.

[TobyB]

You probably won't find much bigger numbers overall,

but your curves might smooth out quite a bit, depending on how

well you were able to get the 38/38 to cruise and transition...

 

t

[Son of Marty]

Just now, TobyB said:

You probably won't find much bigger numbers overall,

but your curves might smooth out quite a bit, depending on how

well you were able to get the 38/38 to cruise and transition...

 

t

And pick up some mpg's.

[Mark Sucher]

Smoothing the engine out and as an additional benefit picking up some MPG’s probably would make it worth it. Not necessarily in fuel cost. But some simpler pleasure. Thanks again for helping me understand what this upgrade could do.

[xr4tic]

I seriously thought about the Retroject.

 

Pros:

Bolt-on(ish)

All the sensors are built in

idle valve is built in

Keeps the classic carb look in the engine bay

Cons:

Price

Won't gain much HP over a normal Weber

 

Lots of people will tell you to just do a 318 EFI, but you need to source all the parts (manifold, coolant outlet, coolant line), fab/buy an idle adapter, fab a throttle linkage solution, fab/buy a TPS adapter, and/or upgrade the TB (stock is pretty small),

 

IMHO, I'm not crazy about the 318 EFI manifold looks either.

 

HP should be about the same as a Weber 38, but have better drivability/cold start/MPG

 

No matter what solution you choose, you'll still need a fuel pump, ECU, and possibly crank trigger if you want to go distributorless ignition.

 

Personally, I wasn't concerned about the price tag, but I eventually wanted to do ITBs, so I decided it was best to just spend the money on them instead (Winter project)

[Mike Self]

I've often wondered if an existing TBI system--from a domestic vehicle with a similar displacement engine (Dodge Omni, Chevy S10 pickup truck etc) could be adapted to an M10--for those of us who still like to see a carburetor-appearing appendage atop their intake manifold and aren't quite ready to take the plunge to full EFT...  

[jimk]

Instead of $500 on a steering wheel that does nothing for car performance, I'd rather put the money to work.

[xr4tic]

38 minutes ago, Mike Self said:

I've often wondered if an existing TBI system--from a domestic vehicle with a similar displacement engine (Dodge Omni, Chevy S10 pickup truck etc) could be adapted to an M10--for those of us who still like to see a carburetor-appearing appendage atop their intake manifold and aren't quite ready to take the plunge to full EFT...  

 

 

Not sure if he ever finished it.  I picked up a 2 barrel TBI unit off fleabay, but it's pretty big, might be too much for a 4 cyl.