Turbo YR - EFI Upgrade

[bjuengling]

I have a 64' and did an engine swap to a YR Turbo with a weber side draft carb. I am having tuning issues with the weber and decided to upgrade to EFI technology. If anyone has made this upgrade, I'd sure like some input. Is there a kit or combination of parts I can piece together?

[Nashfan]

I made the jump to EFI in 2015, and although it took a awhile to get the tune right, I would never go back to a carbed set-up on a turbo. Best fuel mileage on either my YH or a 45DCOE was between 16-18 "around town" and 22 on the highway. Best drivable safe boost with the weber was 18psi and I couldnt get it until 3rd gear. With the EFI dialed in, I can get over 20psi in second!! and I get 22-23 miles per gallon around town and 24-25 on the freeway. The oil stays nice and clean, the valves stay nice and clean and and so do the plugs! This is the hard way to EFI, as the injector bungs are welded into the top of the intake ports. The 45DCOE Weber has been converted to a throttle body- it has been gutted and has been bored out to 45mm on both throats, and the blades open synchronously. For all practical purposes, it flows as much air as as a quadrajet!. The throttle postition sensor is on the backside, and the manifold is a very heavily modified Crown manifold to attach the weber to the turbo. The injection system is by SDS and uses a crank triggered distributorless programmable timing.

[Nashfan]

Just in case you want to do something real about your cooling on a budget, heres a link to my "Bellmouth shop" where you can purchase a 3D printed Bellmouth for the fan intake. I have been experimenting with these for years now, and it is seriously amazing what happens to the cooling when the intake to the fan shroud is modified in this fashion. The reason for the blades on the bell is to combat air spin as it enters the fan, which is a huge flow loss, upwards of 9%. Much the same situation as if you had a vacuum cleaner nozzle in you car, and stuck it out the window, and tried to figure out which way to aim it to get the most airflow into the nozzle. Aiming it into the headwind will get you the most, aiming it away from the wind will give you the least. When its aimed away, the air has to turn around and begin chasing the nozzle. This is what air spin is!!. This same basic idea is why turbo compressors have inducer blades on them... so as to allow air to be drawn in from in front of the rotation. Guidevane B 8.3 shorty has been tested on a magfan and the owner has been quite happy with it, really makes a difference in hot weather.
https://www.shapeways.com/shops/nashfan-bellmouth-shop

[acarlson]

Don't know what your timeframe is but you might take a look at Ted Brown's EFI systems: https://corvair-efi.com/brown-efi/turbo-150-180-hp/.
He may have a solution which works for you in the fall...

Alec

[Nashfan]

Heres a relatively simple carburetor option you might consider that takes care of most of what is wrong with both webers and Carter YH's. It is a Mikuni flat slide carburetor, and they have fuel injection like throttle response and power

[66vairguy]

Heres a relatively simple carburetor option you might consider that takes care of most of what is wrong with both webers and Carter YH's. It is a Mikuni flat slide carburetor, and they have fuel injection like throttle response and power

That is interesting. Can you post the model # and what it is used on?

[Nashfan]

Heres a relatively simple carburetor option you might consider that takes care of most of what is wrong with both webers and Carter YH's. It is a Mikuni flat slide carburetor, and they have fuel injection like throttle response and power

That is interesting. Can you post the model # and what it is used on?

Those carbs were last used in O.E. applications on Harley motorcycles and also Yamaha's. Heres much more information
about these: http://www.v-performance.com/products/a ... kuni_carbs
kmart356 over at Corvair Center has been a pioneer in using this carburetor, and he worked with the folks at Vintage Performance to make it happen! Slide carbs have always been a better carb than butterfly types because the fuel air ratio can track the actual airflow over a wide range of throttle openings and flow much more air for their size than a butterfly type can. They have a natural variable venturi as opposed to a fixed venturi and variable area like butterfly types. Also, because of the slide movement, area is gained in a proportional way instead of a wild magnetic hysterisis type curve that is typical of a butterfly opening. They were the last carburetors used in F1 before going to fuel injection!!
Perhaps these would have been used in automotive applications more often long ago, but the big bugger in the old days was that the only other application for them were small displacement motorcycles and those did not need accelerator pumps so they didnt have them! The HSR's do have accelerator pumps and do lend themselves to automotive use. The HSR45 is an ideal fit for use on the F-flow Corvair Turbo, as it is nearly the same size as the turbo inlet!

[66vairguy]

Thanks for the information. Yes variable venturi carburetors have advantages, especially with the turbocharged engine. I've tinkered with the old SU types and Ford used mechanical variable venturi carburetors before going to EFI.

[bjuengling]

Thanks for all your help. I did call Brown EFI and it looks like a fix might be available soon. I have asked the tech at the shop I use to review this and hopefully, I'll have it on the road soon.