Tuning Simple tuning upgrades

[dangfiat]

Now that I have the little 500F with a 650cc running well, I'd like to do some simple performance upgrades and see if that gives me a little bit more uumph.

I know on Mini's, you can do a stage 1 kit (K&N air filter, better intake manifold, exhaust, new needle) and get a decent bump. They all quote 20% or so on the 998

Was thinking of doing the same for the 500F, and installing:
1. Cone filter directly off the carb (or do one of those 90degree airhorns)
2. Sport exhaust (any suggestions here?)
3. Bigger jet for the 28IMB: 115 --> 120

Thoughts on if this would give any meaningful power increase? I know it won't be much, but maybe enough to feel the difference?

Thoughts welcome, and as always thanks

Daniel

 

[bugsymike]

Now that I have the little 500F with a 650cc running well, I'd like to do some simple performance upgrades and see if that gives me a little bit more uumph.

I know on Mini's, you can do a stage 1 kit (K&N air filter, better intake manifold, exhaust, new needle) and get a decent bump. They all quote 20% or so on the 998

Was thinking of doing the same for the 500F, and installing:
1. Cone filter directly off the carb (or do one of those 90degree airhorns)
2. Sport exhaust (any suggestions here?)
3. Bigger jet for the 28IMB: 115 --> 120

Thoughts on if this would give any meaningful power increase? I know it won't be much, but maybe enough to feel the difference?

Thoughts welcome, and as always thanks

Daniel

There are many on Forum who can give more detailed information, but in general terms anything that increases the flow of air/fuel through the engine helps.
Whilst a cone filter may make the engine "sound" faster, drawing hot air from the engine compartment doesn't do a lot. If you can draw cooler air it is more dense (higher oxygen content) from away from hot engine, possibly a vent and ducting?
A well designed sports exhaust can help.
After that the main issue I suspect is head design, in the old days people fitted multiple carbs to increase flow on engines , but given the inlet design on yours probably not an option, though a larger carb jetted correctly as you increase the state of tune will help, as would a reworked cylinder head with larger valves and increased compression ratio, although fuel quality may restrict that option due to pinking/engine knock.
Can you follow the Abarth route?
Apart from that you have already started along the (can't beat cubes route) as in "there's no replacement for displacement."
As a youngster I had a 997cc Ford, the 1500cc engine was a almost direct replacement apart from changing the spigot bearing in the flywheel and bending the accelerator arm up slightily to match 5/8th's inch? taller engine. That gave lots of smiles and was a popular mod.

 

[Toshi 975]

Can be a long and slippery slope once you get away from the standard set up but can be a lot of fun with ups and downs not to mention the potential expense. As ever there are the four main pillars of tuning, the head, the carb, the exhaust and the camshaft.
I have my own preference for the sport exhaust I like as I do not go for “noisier the better” for road use.
There are a number of options for carbs but all require suitable manifolds and setting up.
One of the biggest gains like Mike said is the cylinder head. Upping the inlet valve size, a modest skim and some porting is the way to go I believe.
The 35/75 is regarded as a good sport / fast road option and the 40/80 takes it that little step further.
To pick up on Mike’s point about cool air into the carb, there are options for holding the engine cover open to get more cool air around the engine. Some are modest and some extreme. Plenty of pictures around.
I know it is difficult for you guys in the US but if you can beat hold of things like a spare cylinder head to work on then just swop it makes life so much easier.

 

[Bounding Bambino]

There is unfortunately a limited amount of external bolt-on's you could do to the stock 500 engine to give somewhat of a noticeable performance increase. Unfortunately gains are really seen by doing head modifications, and then cams and such added on. The stock initial intake runner size hole is honestly laughable, and some decent gains can be had just by opening up the intake hole, which can then be accompanied with a larger carb as things progress. Unfortunately this will require a 2nd head, or potential downtime on your current head, and you can also risk opening the intake runner too much and grinding thru the head.

If you want to open it up slightly. You can just "massage" the initial intake hole slightly with a dremel. Dont forget to open up the intake spacer slightly as it is also a restriction if you have a larger carb then stock(26). Might get you 1-2hp gain.

I am currently building a engine dyno for these engines to test and experiment with modifications to see where gains can be had. On my 540 engine i did some cnc porting on the head with a completely re-shaped intake runner and spacer. I have a few carbs to also test with. I hope to get it done asap, because the curiosity has been bugging me for a while.

 

[dangfiat]

Thanks folks! Looking forward to your dyno experiments Bambino!

Eventually I'll probably self port a head and get it skimmed to bump the CR to something like 9.5:1 & up the intake/ex valves. Not sure if I'll go upto 700cc, might just stick with the 650. Will cam & carb it as well

Going to enjoy the little bugger as is for a bit, let the wallet recover from the purchase

 

[the hobbler]

Thanks folks! Looking forward to your dyno experiments Bambino!

Eventually I'll probably self port a head and get it skimmed to bump the CR to something like 9.5:1 & up the intake/ex valves. Not sure if I'll go upto 700cc, might just stick with the 650. Will cam & carb it as well

Going to enjoy the little bugger as is for a bit, let the wallet recover from the purchase

I have put my thoughts on the tuning of the 650 engine down on paper---if you would like a copy, contact me direct and I will e-mail a copy to you, and then you can decide which steps tp take. [email protected]

 

[Toshi 975]

If you want to open it up slightly. You can just "massage" the initial intake hole slightly with a dremel. Dont forget to open up the intake spacer slightly as it is also a restriction if you have a larger carb then stock(26). Might get you 1-2hp gain.

The Bounder is completely right about this when applied the a standard 500 head which has a 26mm inlet port as opposed to the 30mm on a 126 head. The carb mounting studs are the same so it is easy to drop a 126 carb gasket over the studs to see what material to remove then use a 126 carb base, gaskets and a Weber 28IMB carb.