by purches graeme » Wed Feb 08, 2017 9:10 pm
I saw there two - interesting!
I am in the middle of converting my '86 Atmo to a Quick Fuel 4-barrel carb. The Quick Fuel is basically a Chinese manufactured (beautifully made) but US designed copy of a Holley, but easier to set up. Google Quick Fuel BD-450-VS 450 CFM Carburetor Black Diamond 450 CFM Vacuum Secondary for a look. Lots of great feedback on-line about these carbs, and some good videos on U-Tube.
All easily adjustable, including the vacuum secondary which like mixture, is screw adjustable rather than having to change springs. It also has an electric choke.
This model has a Teflon coated body, which is claimed to reduce the internal temperature of the carb by 6 degrees - useful in a rear engined beast where the engine compartment runs fairly warm.
450 cfm is a bit larger than the usual 390 cfm Holley used for PRV V6 conversions.
Both my Atmos have been successfuly running Weber DGAS with 38 mm chokes up until this conversion.
The Quick fuel is not nearly as tall as the DGAS, so we are machining the inlet manifold and moving the carb mount further rearward to better match manifold port lengths, with a 2 inch machined alloy mounting block welded to the inlet manifold and topped by the usual fibre insulating block. This will allow us to retain the original air cleaner, in which I run an Australian made SAAS model SF142RE free flow filter insert, designed for V8 hotrods (14 inch diameter and 2 inch depth).
The inlet manifold is also featuring a splitter to improve flow from each side of the carby to the respective inlet ports on each side, and the extra height from the manifold ports to the base of the carb will also increase gas velocity.
In my Mini racing days I my car had its carb mounted where the speedo used to be on a long manifold, and the improvement in low end torque in particular was amazing.
The lot will sit on a rebuilt engine with ported heads, slightly higher compression, the removal of all water heating to the inlet manifold and carb area, new rings/bearings, cams ground to about Stage 2 spec with spec help from Martin Faulks (thanks mate!), and a custom made extractor system each side running into separate mufflers with a balance tube, All of the porting has been designed to not only improve flow but to increase gas velocity.
The engine is now back together, and the inlet manifold and exhaust work underway.
My son, who runs a workshop in Auckland specialising in performance stuff, has been doing all the hard yards on this, fitting around his usual high workload.
I will post a heap of pix and a link to a video clip including sound once the work is complete - probably still 4-8 weeks away.
Meanwhile, I am suffering Alpine withdrawal systems, as my blue '90 Atmo has been in the paint shop since July for a full respray. The guy doing the work is Howard Savage, an Alpine whizz who worked on these cars from when they were new, and emigrated here from Ireland and now runs a paint and panel shop here. He did the repairs and total respray on my '86 after its mishap last year., and is also fitting the job around other work to help keep costs down, He did the repairs and total respray on my '86 after its mishap last year,
Great to have knowledge and experience on my doorstep!
Cheers
Graeme
