Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Winter game

Winter in Belgium is a better time to perform some technical ''bricolage'' than drive under rain or worst on salt road.
So a play a little under the hood

- put a good coat on the exhaust manifold to keep the under hood cooler and keep his catalytic part as warm as possible (it will help for the exhaust analyse on the technical control)


- if you have the sport exhaust full line and the clubsport map what can you do more ?
Changing your 55 mm (on top) throttle body by an 65 mm (at bottom) of the 2,3 Mustang EcoBoost maybe ?
Surprisingly the fitting size is exactly the same and even better the inside manifold diameter is 67 mm (btw the smallest diameter in the complete air tubing is 65 mm)


- while removing the original throttle body it was quite oily... This is not good for a direct injection because there is not fuel injected in the intake to clean up the intake valves and ports. Let's put a basic oil catch can instead the direct tubing from the head cover to the throttle body.


Final result (no any hole was drilled in the body or the engine) :


Oil catch can


And so far that i have already dismounted the engine air circuit let's also put a conical foam air filter.
Why conical ?
Because the original paper one is so thigh in the air box that only a small circle just at the air entry of the box was dirty all the rest of the filter was quite totally clean !
A conical will offer a better air circulation.


First static results:
- engine start immediately without issue
- throttle is working perfectly
- at static RPM increase when pushing the pedal seems more quick and load a bit more loud
- the engine is also more chaotic when cold. After 2, 3 minutes it's back to normal. I think that it can be related to the fact that the engine get more air and the ECU star to compensate when the lambda probe are enough hot to get measurements.

Total cost was less than 280 £
When the weather get a bit more better a will proceed to a road test and an post an update

Nice work. Which year & model is this?

Dada, I can follow your thinking on the upgrades, interesting that the cold engine running is affected, though perhaps not entirely unexpected dependant on the cold start system design..?

As John typed, nice work. I know not the kit fitted to modern Morgans though one other modern car I know of has an air/oil separator to reduce oil being drawn into the intake, and which is known to create issues in time. Does the Morgan have such a device/system..? I have read of all sorts of methods tried to clean the fouling of the inlet system on D.I. engines, there has been mention of it on this forum too..

It is my loved 2016 Plus 4 GDI
Morgan didn't fix any air/oil separator on this model and honestly I was quite surprise to find oil drops a little bit everywhere in the intake manifold just behind the throttle body after only 15.000 km
I think a will invest some € in a deposit cleaning spray in the coming weeks.

Thanks for taking time to reply to my questions

That's a very neat job you've done there but I will be very interested how it drives when you road test it and maybe even put it on a dyno to get some numbers.

I say that because I'm thinking of upping the throttle body size on my 2 litre Zetec but your change is quite big.

You've increased the throttle area by almost 40% and I would have thought that would slow down the gas speeds at lower RPM and possibly therefore reduce the torque in the mid-range.

I will be very interested to read your evaluation as it might influence my thinking.

Ivormog... Genuine query... Is gas speed still an such issue in these days of injection?.... In a carb where speed of flow pulls petrol up jets then it's important... But with injection taking care of the mixture, might a lower gas speed with less turbulence be an advantage (providing its was still moving fast enough to keep the fuel droplets from falling out of suspension)... And a larger inlet just making it easier to fill the cylinders? ...... Intake dynamics are a bit of a black art... And one I'm not well versed in... A single 65mm bore doesn't seem a lot feeding a largish motor compared to the 4x42mm TBs feeding my 998cc Suzuki motor

I'm sure someone will enlighten me. :-)

K

You might well be right on this but I have read a number of articles where going too big on throttle bodies has affected the mid range.

However that was on ITBs and it might be different on a plenum throttle body which is why I will be interested in the outcome on this to maybe influence my thinking.

But I guess the other question is if it improves things with a bigger throttle body, why don't OEMs do it?

As the manifold would also accept the 65mm TB maybe the GDI is tuned to allow this larger TB on higher horsepower engines.

Certainly I'm not knowledgeable enough to answer that stuff... At the end of the day a trip to the rolling road before and after tells no lies (as long as it's the same rolling road!) .... As for 'why don't OEM do it?'... You could say the same about the gains obtained from a decent aftermarket exhaust system, when if they were fitted to all cars at the factory en masse the cost difference would be minimal. Manufacturers move in mysterious ways!!

K

Tuned inlet lengths and diameters remain important with particularly with naturally aspirated engines. In this case the new, larger diameter, throttle body is from a turbocharged engine therefore the parameters would be quite different. The increased size of the throttle body may increase the power at the top end but in combination with the sports exhaust system and the different air filter would almost definitely only give the best results with a re-map and, in fact, may reduce the peak power. One should not assume that the re-map for the sports exhaust system would be sufficient. I don't know how the ECU is set up but I would suspect that at full throttle and high revs the system is not utilising the closed loop feedback but working purely on the fuel map. In order to get the best power output and to protect the engine this is normally set slightly richer than the stoichiometry air–fuel ratio used for emmision requirements and fuel economy. In the worst case such a change may lead to an excessively lean mixture at wide throttle openings and burn a hole in the piston or damage valves etc. The functioning of fuel injection on a GDI engine is very complex and relies on multiple micro pulses of fuel injected into the cylinder in order to ensure a thorough mix of air and fuel for the combustion process. In effect it is poorly burned droplets of fuel that cause fine carbon particle output on GDI engines that in some case may exceed the fine carbon particle output of diesel engines.

A larger diameter inlet tract could also reduce the velocity of the intake are at intermediate rpm. The result of this would be to reduce the intake flow into the cylinder as the valves open. In other words reduce the charge entering the cylinder. This in turn would reduce low and midrange torque.

I recall a Honda car 4 valve engine that only operated one of the two inlet valves once a certain RPM had been reached. This was specifically to increase intake velocity, and therefore cylinder charging, at low to intermediate RPM, in order to improve torque in that regime.

Mind you I'm not a qualified automotive gas flow engineer so all the above is probably a load of tripe.