Hi everyone,

last year I did AFH engine swap in my skoda felicia.

The engine was fully rebuild with forged conrods, brand new pistons, rings, bearings.. etc.

For fueling I'm using classic honda cbr 600 fx/fy carbs with homemade intake manifold. For ignition I'm using ignitech programmable ignition system. Exhaust consists of raceland exhaust manifold and the rest is 50mm pipe with two straight-way absorbers. Using wideband onboard lambda analyzer to check the afr.

So and what's my problem.. I'm still trying to get some power out of it.

Currently I'm running on 1.12mm(0.0446") jets (what is still much smaller apart of that what are other people using on this engine), getting AFR around 13-13.5 on full throttle from 4000 to 7500 rpm.

I already tried to use 1.16mm(0.0462") getting AFR around 12 and then 1.22mm(0.0486") jets with AFR around 11. Both made less power.

Here is my RR pre-tuned ignition map.

Currently I can go from 0 to 100kph in 11.5 sec what's little bit slow I think if that engine is going to make around 120-130hp (with 900kg car).

Does anyone have any solution how to get more out of it?

I'm worried about the cams, I didn't do anything with them, but the previous owner.. who knows? I think that they can be from 55kw version..

Thanks to everyone for any solutions and sorry for my english :).

Here's small video with acceleration

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Edited 19 July, 201313 yr by Metiu

I'd certainly look into the camshafts if you're suspicious..how much power is it running currently?

Or when you say it ran worse running richer was that based around feel of you driving it?

I'd try some some 1.14mm jets to richer it up, aiming for the high 12s AFR wise, but depends how continually you give it abuse in a given period?

Is the cam timing definitely correct?

I don't like the look of the foam over the pipes on the carbs, it could be restricting them to atmosphere - do your slides open up fully at max RPM?

Ignition doesn't look miles away from how I'd imagine it would end up.

What gearbox are you using? You be expecting too much, but then again 11.5 to 100kph doesn't sound too good, but there are a lot of variable factors indeed

Just watched your video - dont usually need to rev one that high, but then again it sounds like the gearbox is taking it right off the power every change, have you considered a shorter ratio gearbox?

Hi,

I was comparing the jets during acceleration from 40 to 90kph on second gear and then reading correct time from each frame in the video (getting precious times with tolerance around 0.2 sec).. that's how I tuned my current setup to its best. Changing jets to bigger ones or changing ignition made it always worse.

I'm using shortest original gearbox available for felicia, running 100kph on 2nd gear at 7500rpm - don't know how much it's in comparison to polo gearbox.

I also tried to run carbs without filters, but I wasn't getting any improvements.

I don't see how cam's can affect it? Surely only AFH cams can fit?!

I was thinking about the cams because of jets I'm using... bad cams means I get less air in the engine and because of that I must use much smaller jets than everyone else..

or.. ?

Today I will check the cams and we'll see.

So I checked the camshafts and they're AFH ones.. 036E on intake and 036T on exhaust

Its not really worth going by what anyone else is running jet wise, carbs vary massively and used ones have often been modified

Can't help on the power front, but if you were going to look at the gearing, then you can fit the 4.24 final drive from a Fabia 8v gearbox into the Felicia box - it's a straight swap. Also, there's a 4.8 final drive which was in the 1.0 Fabia gearbox that will also fit. I run the 4.24 in my Felicia rally car, and it lowered the gearing a useful amount.

What car are the ignition leads from? And spark plugs? Do you know what ohms they run at? I don't know what ohms you need for that ignition, 5k probably.

ignition leads are from CNG bus.. but it doesn't matter, I have stock leads too, tried with no difference

spark plugs are NGK BCP7ES, had different NGK 3-contact plugs too, but again, no difference :(

Last chance is the intake manifold, I'm not using straight pipe because of interior heating, as seen in the picture

But can only this make 20hp (or bigger) difference?

How much costs bogg bros intake manifold?

Change up much earlier and fit a closer ratio gearbox.

Rev'ing to 11.000.000RPM won't help your 0-100kph time

also how are you measuring your times? Could it be that inaccuracies in this combined with spending most of the time out of the power band are more of a problem than anything mechanical?

Just watched your video - dont usually need to rev one that high, but then again it sounds like the gearbox is taking it right off the power every change, have you considered a shorter ratio gearbox?

:)

so today I spent all day trying to get some hps from it.

I removed the foam filters as harris told.. and I got interesting improvement, then changed the intake to straight one and jets do 1.22mm. Getting AFR around 12-12.5 with full throttle.

Now my time 40-90km/h is 6.46sec instead of 7.35sec with filter, 1.12jets and different intake.

You asked how I'm measuring :)

I'm recording video of my tacho going on 2nd gear from 40-90km/h without changing gears. On same piece of road, always measuring 4 times. Then I dowload it to my notebook and measure the time frame-by frame getting times with divergence around 0.1sec. Then I calculate average time for some conclusions.

With wideband lambda it seems to be enough for some base-tuning before going to dyno.

Today I'll check my 0-100 time, I hope for something around 10.5sec.

I was thinking how to get more air in it, but now it looks like only cams can get me more power.

10.5 isnt great, then again your car will be a bit heavier than a mk2 or mk2f

The gearbox is killing it, change that

have you considered a shorter ratio gearbox?

Change up much earlier and fit a closer ratio gearbox.

The gearbox is killing it, change that

Have you thought about swapping the gearbox?

Lol I requoted mine because I'd said it early on and nobody seemed to notice.

In other news try a gearbox, doesn't matter what your engines doing if the way it's being delivered to the wheels is no good

have you considered a shorter ratio gearbox?

Change up much earlier and fit a closer ratio gearbox.

The gearbox is killing it, change that

Have you thought about swapping the gearbox?

+19 would be much better with a shorter box.

I could practically hear your valves going fuckfuckfuck sounds nuts lol

yep.. I will look for some fabia gearbox to get the right final drive, maybe 4.24 will be enough? Now I'm running 4.11 (shortest stock felicia)

Now it's performing much better.. it's not rocket, but runs better

Doing times around 10.7-11.3 sec, measured by gps racechrono in my mobile phone.

Today I weighted it.. and result is 1010kg, what's a little bit more that I was expecting for (around 900kg).. so there's the problem :)

Yeah weight and gearbox - its only a 1.4!

last few days I spent a little bit more time with tuning, now using 1.16mm jets, getting afr around 12.5-13.

Today I went to dyno, result is pretty good

125ps at 6900rpm/132Nm at 6000rpm

With limiter at 8000rpm it would be around 130ps or more.

Seems about right to be honest, I'd say to make it more lively you'd need:

More suitable gearbox

Lighter car

Less expectation - its still only a 1.4 16v :)

Although, everything seems to peak a bit high up the rev range, was the RR calibrated correctly?