First off, I have to thank Greg Latham from GSL Rallysport for the quad carbs and exhaust, and good luck to him with his racing.

Above: my lada cevaro

I thought I'd share some info on my car, because the setup on it is not really all that common these days, and it might be interesting for some people.

Being a engineering student, I wanted to somewhat improve the performance of my lada cevaro without burning a hole in my wallet. Having looked into fuel injection (it originally had one double brl carb), dual webers and even supercharging, i stumbled across an ex-rally lada samara on ebay. This was Greg Latham's samara that sadly rolled at the rally of Lithgow (its on youtube ). Impressed by the efforts put into this car, i inquired about the quad carby setup, and found myself buying the full exhaust system along for a very decent price, thanks again Greg.

Above: the quad carbs on Greg's samara

I should say the samara is underrated. It may be somewhat underpowered, heavy and perhaps not the best looking, but if taken care of, very reliable and extremely simple to work on.

The manifolds for the carbs were manufactured using exhaust piping, and the whole setup was basically bolt-on for me, at first anyway. The complications and improvements are explained in detail further.

Above left: the old and new exhaust systems

The exhaust system is a straight through 2” with headers. Nice tone, but a tad loud above 3k. Painful to fit the headers though, because the head is not cross-flow, so the headers are at the back. This meant the brake lines heat sheild and heater hoses were in the way. Heat shield was bent out and heater hoses bent around.

Above left: cone filters on carbys, above right: aluminium airbox

The original plastic airbox caused all sorts of dramas because it was too big to fit in, causing the rubber manifolds that hold the carbys to rip. To fix this, a set of four motorcycle cone filters were installed. These were later found to be quite restrictive to airflow, and after one popped off due to backfire and was run over, they were scrapped. Since some filtering needed to be implemented, an aluminum airbox was constructed using sheet aluminium, aluminium L sections and a ton of blind rivets. Motorcycle filter foam sheet sat on top for the filtering. Perhaps an air scoop in the bonnet will be fitted to let it breathe fresh air.

Above: the carbys

The carbys (cvk40 x 4) themselves are off a 1994 kawasaki zzr1100 (zxr11) as far as i know. These are fairly rare and the rubber manifolds are hard to find, let alone jets of any kind. The bike is a 1.1l 150hp 16 valve beast that revved to 10500 rpm. I was worried at first how the carbys would run on a 1.5l. And there was resaon to worry: jetting was by far the biggest issue to date.

Above: the fuel feeding system in the cvk40s

The 40mm bore in the carbys meant airflow was low, and so was the vacuum. The bike must have got good airflow from high revs; my car, however, wasn't going to rev that high. As a result, a really lean mixture was observed. The original main jets were 1.3mm, which were replaced by weber 1.4mm ones, which were progressively drilled to 1.8mm, then 2.0mm. When i get a chance, i will take them up to 2.2mm. Drilling these accurately is difficult, so care must be taken to hold them upright and straight.

The jet needles tended to be too fat too, and i couldn't find any thinner ones, though i did get ones with a sharper taper from SA. The way too fix this was to drill the needle collars. After overdrilling these and refilling with solder, these were finally brought to a perfect 3/16”. The slow jets (idle etc.) are yet to be jetted.

Note that jetting was based on road tests and reading plugs, no dynos or anything, but i thing it was done pretty well. I tried a gunson colortune sparkplug, but couldn't really use it on higher revs because of the danger of overheating the plug. Perhaps a lambda sensor would have been better, but never got around to fitting it. Since the car was a daily driver, jetting has been going for over a year now, and who knows when it will be finished. Its pretty quick though, kills a number of stock cars at the lights.

Above: programmable ignition

The old ignition system had an rpm advance within the distributor and vacuum advance from the intake manifold. The new carbs allowed almost no vacuum to build in the manifolds, no vacuum advance could be used, so a programmable ignition system from jaycar was purchased and assembled. After some fiddling around with the output signal (had to be boosted from 5V to 12V), this was successfully wired up to the original transistor module and the rpm advance in the dizzy disabled. A toyota celica map sensor was also added. The ignition system allows a 256 point map to be programmed, based on revs and load (manifold air pressure). Great feature for the price! Only downside was the handheld programmer, which is time consuming to use.

Above: pressure regulator

Since these carbys were meant to be gravity fed (or a low pressure <1psi pump), my mech pump was too much and some overfilling was noticed. Greg, however, never ran a pressure regulator on his, still don't know how. A low pressure fuel regulator is hard to find, but this holley one works pretty well for the price, however i had to replace the regulating spring inside to get the required range.

Above: polished head ports

The head had some work done while i was waiting for a new head gasket from Russia. Am looking into getting a performance camshaft from there too someday. Maybe even titanium valves? Nah... im dreamin

Above: thermostat (or lack thereof)

Some issues had arisen when the thermostat wouldn't open up properly (~130C going to uni one day almost had the head crack), but instead of getting a new one, i decided to remove it completely. Since the samara/cevaro thermostat is one piece with the housing, i replaced it with some brass plumbing pieces. Warms ups slower but runs nice and cool on highways (~65-75C) and the radiator temperature is more closer to engine temperature than it was before, probably due to higher coolant flow rate.

Above: custom guage faces

The faces i designed in photoshop and printed, then fit them on and added aluminium rims. Worked out how to make smoked face guages and was going to build some, but very time consuming to do properly.

Above left: engine bay, above right: interior (could do some work)

When this was written, the fate of this car was being decided. Being quite thirsty and lacking some creature comfort features like a/c, i am moving on to a renault 19 that i am repairing from a collision. Whether to rebuild the lada for rally, keep improving it for the road or who knows... not sure yet.