32/36 Carby & Ported Manifold Package

Bolt on 32/36 carby and ported manifold package designed for an Isuzu G series SOHC engine (G161, G180, G200) in Holden Gemini, models TX-TG, but could easily be used in the engine bays of a Jackaroo, Rodeo, Chev Luv, etc. Will also bolt onto 4Z series engines.

This carby and manifold package designed for improved flow and good horsepower increase with improved throttle response and acceleration. Ideal to replace the standard Nikki carby. Can also be used for blow through turbo application.

I supply either a Weber 32/36 DGV or Holley 32/36 DFV style(the Holley is a Weber copy), see down page for prices. I can also supply chrome air cleaners to suit both the Weber and Holley carbys and offer a discount if purchased with a carby package. Also, email me to get price/availability on TIG welded aluminium air boxes for blow through turbo setups.

This package consists of either a fully reconditioned carby or a brand new carby (see down page for options), an inlet manifold ported to suit the chosen carby, an new adaptor plate match ported to both the manifold and carby, and fitting kit.

WEBER/HOLLEY CARBY

The 32/36 carby is a twin barrel downdraught carburetor with mechanical secondary, 32mm and 36mm butterflies, with 26mm and 27mm main venturis.

The Weber 32/36 is the original carby design made in Italy by Weber. Holley then manufactured these carbys under license to the same specs as the Weber. There are several configurations of 2 barrel downdraught Webers, the DGV probably being the most common. The DFV variant is simply a mirror image of the DGV, so the primary and secondary barrels are on opposite sides. The DFV also has a different air cleaner mounting cut-out to the DGV, The DFV being oval in shape, whilst the DGV being more rectangular.

There are also several choke options available, DGAV is "aqua" choke, DGEV is "electric" choke, and DGV is mechanical choke. I supply my carbys with no choke at all, to increase air flow and engine power potential. For a detailed description of several Weber/Holley carby variants and options, check out XXXXXXXXX.

These 32/36 carbys were originally fitted to 1600cc - 2000cc engines such as from Ford Escorts and Cortinas, and were also fitted to 2.3litre 4cyl engines in the US. They flow plenty of air, enough for a worked 2 litre to make really good power.

I have made 150hp@wheels with one of these carbys on a 2 litre Gemini G200 in a blow through turbo configuration, see my 'stage 9' page. They can also support up to about 125hp@flywheel in a non-turbo application, but on the average Gemini G161 1600cc engine, you could bolt one of these carbys on and with a good flowing head, decent cam and good flowing exhaust, you'd expect at least 100hp at the flywheel if tuned properly. Probably more like 110hp with a G180 or G200.

Dyno testing on a stock G180 (from a Chevy Luv in the U.S.) has shown power levels increase from 45hp@wheels to 70hp@wheels by fitting a 32/36 carby, an aftermarket manifold designed to mount a 32/36 carby, and a set of extractors. That's a 56% power increase from a simple carby, manifold and extractor swap. click here for the magazine article.

The mechanical secondary feature of the carby means the secondary butterfly opens when you want it to, you don't have to wait for a vacuum signal like you do with the stock Nikki carby. The progressive feature of the carby means the secondary butterfly opens after the primary. This gives crisp throttle response as the air velocity remains high at part throttle as you're only using the primary butterfly, whilst still flowing pant loads of air when the accelerator pedal is floored and the secondary opens. The 32/36 carbys are also surprisingly economical when tuned properly, which is a great bonus as you get both a performance and economy benefit.

The Weber 32/36DGV carbys are brand new, whilst the Holley 32/36DFV carbys are completely reconditioned from a leading carby remanufacturer in the United States. They are in as new condition and are flow tested before being vacuum wrapped and sealed in their box. The flow testing ensures the carby performs as it should before being fitted to an engine. I specify the carby options and prices down the page further.

The choke mechanism and choke plates can be removed to increase airflow through the carby. Without the choke, at worst, in a cold start situation, the accelerator pedal may need one pump to get enough fuel into the manifold to allow initial combustion. As the engine is cold, it will idle at a lower engine speed until normal operating temperatures are achieved. It may be necessary to hold the engine at a fast idle speed (1800 rpm) for 10-20 seconds until the carburetor idle circuit will sustain the idle.

If you're after even more power from your engine combo, I can supply a brand new Weber 38 DGES carby which has a pair of 38mm butterflies and larger main venturis for even more flow. The butterflies are synchronous meaning they both open at the same time. This increases engine throttle response and acceleration, as the cost of fuel efficiency. They are fitted with electric choke as standard.

INLET MANIFOLD

The manifold included has been modified to increase engine breathing capability and horsepower.

Firstly the carby mounting area has been modified and extensively ported to suit the Weber adaptor plate, as per my Manifold Modification page. This has three benefits:

It increases overall airflow from the Weber carby to the inlet ports by smoothing the transition from the carby to the manifold. More airflow equals more power potential.
I also concentrate on directing more flow to inlet runners #1 and #4 as these cylinders often get less air/fuel mix than cylinders #2 and #3 due to their extra length and the integral bend in the inlet runner. You will usually see piston damage if the engine is pushed to its limit on the outer cylinders #1 and #4 because of this design flaw. So balancing up the airflow to each cylinder not only protects those outer cylinders more from detonation, but also helps those cylinders develop more power.
The manifold modification increases the plenum volume which in standard form, is very much on the small side. General recommendations for optimum power is for plenum volume between 1 to 2 times the volume of the engine. ie, for a 1600cc engine, the plenum volume should be between 1.6 and 3.2 litres. The standard plenum volume is a lot less than this recommendation, so porting and adding the adaptor plate increase the volume closer to optimal, which can increase airflow and power.

To make sure you get a nice sealing surface, the carby mounting face is machined flat, as is the thermostat housing flange.

ADDITIONAL OPTION - The stock Gemini inlet manifolds are heated by the engine coolant as there is a water cavity directly underneath where the carby bolts to (the plenum). This heating of the manifold is for emissions purposes, as it warms the air/fuel mix which promotes better fuel atomization and more complete burn of the mixture.

However this hotter inlet air is bad for horsepower, as hotter air has a lower density, which means less oxygen molecules for a give volume. At an additional cost (see 'Additional Options' down page for details), I can block the coolant flow to the plenum and re-route the heater hoses, therefore the manifold is no longer heated and you get a gain in horsepower from the cooler denser inlet air.

ADAPTOR PLATE

Also included in the package is a Redline carby adaptor plate, which allows the Weber carby to bolt onto the Gemini inlet manifold. The adaptor plate is ported to match the ported inlet manifold for smooth flow transition from carby butterflies to inlet manifold plenum. The adaptor also adds plenum volume to the manifold.

Redline make a nice product, I have used their adaptor plates many times before and their kits are nice.

EXTRAS

The extras included to fit the kit are an aluminium accelerator cable bracket to suit the standard Gemini accelerator cable, studs, nuts, bolts and washers required for the adaptor plate, and the gaskets required to seal between the manifold, adaptor plate and carby.

The photo below shows the Nikki throttle linkage adapted to suit the Weber, along with the fabricated aluminium accelerator cable bracket. The stock Gemini accelerator cable fits into this bracket without any modifications and works just as the standard setup worked.

Gaskets are supplied and carefully trimmed to suit the ported manifold and port matched adaptor plate. Care is taken so that no gasket material protrudes into the air flow to make sure no horsepower is lost.

THE PACKAGE

In summary, the package consists of the following:

- 32/36 Carby - either brand new or fully reconditioned, assembled and ready to run.

- Ported inlet manifold - extensively ported to suit 32/36 carby and adaptor plate, larger plenum volume.

- Brand new adaptor plate - modified to improve flow, match ported to suit carby & manifold.

- Fitting kit - hand trimmed gaskets, nuts, bolts & studs for adaptor plate & accelerator cable bracket.

Besides some parts that you need to re-use off your stock inlet manifold, I provide everything required to get your new carby running. See note below...

NOTE: the kits supplied do not come with the the standard Gemini parts that can be removed from your stock inlet manifold and carby, such as the Nikki carby throttle linkage, temp sensor, thermostat, or thermostat cover. You need to use the ones off your old stock carby/manifold. If you need me to supply these parts, let me know, as there may be an extra charge, see Additional Options below.

I will supply jetting for the carby which should perform pretty good straight out of the box to suit your engine. I just need some basic specs like engine capacity, head work done, cam specs, and exhaust sizing.

COST: Option #1- Fully reconditioned Holley 32/36 DFAV - $425.00 plus postage.

Option #2 - Factory remanufactured Weber 32/36 DGEV - $535.00 plus postage.

Option #3 - Brand new Weber 32/36 DGV - $595 plus postage.

Option #4 - Brand new Weber 38 DGES - $645 plus postage.

I can also supply (when in stock) second hand Weber 32/36 carbys which are fully stripped/cleaned & partially reco. Kit price is $365. Its not a big saving as there's a lot of time taken up in getting old carbys up to scratch. Click for more details

Email me to get price/availability, and also with your postal address and I can give you a postage quote. To pay for the kit, you can either make a deposit directly into my account, or if you prefer and can send you a Pay Pal invoice, however cost will increase by a few extra $$ to cover Pay Pal fees.

ADDITIONAL OPTIONS: click on part for more details

- Add $5 - Gemini Nikki throttle linkage

- Add $44.50 - brand new rectangular chrome air cleaner with 2.5" element

Normally $55.50, but only $44.50 when purchased with carby & manifold package plus free postage.

- Add $50 - TIG welded inlet manifold water reservoir and heater bypass fittings

- Add $220 - K&N cast alloy Weber carby air bonnet

- Add $165 - TIG welded aluminium air box

- Save $60 - second hand Weber 32/36 carby

If you want any more info feel free to ask me questions at benw@ncable.net.au