Alfasud 16v Dyno Day

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I went with my son to Janspeed in Salisbury on Monday to get the car set up following replacing the ancient Megajolt ignition system with a Nodiz Pro alternative.

The car runs a standard 16v on Weber 40 idfs. We started off at 116bhp at the wheels and finished with 122.5 with K&N pancake filters and 121.6 with the standard air box. Interestingly the standard airbox gave significantly more power and torque between 3,000 - 3,500 revs than with the K&Ns.

The dyno expert Russ advised 15% transmission losses for fwd cars which equates to 144bhp and 142bhp I calculate, Does anyone know what the losses are in practice for a standard Sud transaxle?

We have a track day lined up at Castle Combe on the 10th May to give it a good run out and plans for further mods.

Thanks

Adam

[Veesix75]

Ahhh, the black art of rollers and bhp and losses.

All I can say is that if the chap thinks his rollers are relatively well calibrated then that sounds about right and healthy.

Alfa quoted 137bhp, my friends very mildly ported 16v on road cams, road exhaust and std injection and air box showed 150bhp on the rollers we both used, my similar 1700 8v was 129bhp, my 1500 race engine, cams and ported, 140bhp. All flywheel quoted.

You have a benchmark for any future changes, that’s the main thing.

Remember, revs = speed, the higher you’re prepared to take it, the quicker you will be in lap times so you don’t need the torque that low down.

Plus you are probably weighing in at less than 900kg so should go very well.

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Thanks for the feedback Veesix.

I’ll post an update following the track day, hopefully with some video footage.

Going forward we are looking at exhaust and bigger carbs to get more at the top end.

In the meantime it’s nice to have a well set up car to trundle around in.

Adam

[Veesix75]

Bigger carbs might not do that much without other modifications.

I went from 40’s to 45’s on a 1500 full race, minimal bhp increase but some extra torque, but I also went from Weber to Dellorto so the carb type may have also made a difference.

Might be worth looking at chokes and jets first if the engine remains std.

I’m not an expert btw !

Hope all goes well, and it will do more than trundle with 140bhp and not a lot of weight. What gearbox is fitted ?

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Thanks for the advice. It has a Series 1 Ti gearbox (no lsd) which is perfect for the rural Wiltshire roads around my way and the track day circuits we have been on.

[rsfruitbat]

The guy I use called Dave at mek motorsport usually reckons on closer to 20 - 25% losses on his rollers.

Rsfruitbat

[rsfruitbat]

The guy I use called Dave at mek motorsport usually reckons on closer to 20 - 25% losses on his rollers.

Rsfruitbat

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Thanks RS,

I’ve spoken to Dave a couple of times when he was at Castle Combe track days with his son, A very knowledgeable man with a very good reputation. It would be interesting to run the car up on his dyno when I get the chance and following some further fettling.

Adam

[rsfruitbat]

I'm biased but I think he is brilliant.

Rsfruitbat

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Three of us drove the Sud at Castle Combe on Monday.

Given that this was the first proper track shakedown since fitting the 16v engine all went well-ish.

We had a part throttle misfire which cleared after a few full throttle laps and cooling problems as a result of air entrapment which we sorted.

My son who is an ex-kart racer and his mate who is a current kartist gave the car a good workout.

Their analysis; the most fun car they’ve driven round a circuit, pin sharp steering, fantastic grip from the Dunlop direzza dz03g tyres and great feel and bite from the brakes, which are 257mm Alfa 164 discs, Wilwood Powerlite calipers and Ferodo DS2500 pads.

No footage from the camera I’m afraid as I set the contrast incorrectly so you can’t see the track through the windscreen which is a bit pointless.

We have one unresolved issue. The speedometer is not working. The cable is clipped in at the gearbox end properly and screwed into the back of the dial but neither speed or distance is moving, does anyone have any ideas?

Thanks,

Adam

[junior]

Does the inner pull out ? It sounds like its snapped, or not locating at one end or the other.

[rsfruitbat]

If it's not the cable unfortunately it could be the gear on the end of the Speedo drive. They are plastic and tend to crack.
If you can get the cable out then see if you can get a drill onit. Give it a spin and see if Speedo moves.
If you put a thin screwdriver with a 50mms shankinto the gearbox Speedo drive you can then slowly rotate the offside driveshaft. The screwdriver should slowly rotate

Rsfruitbat

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Thanks for the advice Junior, RS
I’ll try all these things and see where I get to.
If the gear is broken what’s the procedure for changing the gear drive?
I know that Mr Sud has steel replacements advertised on his ebay page.
If it is the case that mine is broken then I’ll give one of them a whirl, literally..

[LooLooSud33Spider]

Adam. Is it a sud or a 33 box ?

[rsfruitbat]

Good point Loo
Didn't think of it being a 33 box

Rsfruitbat

[adsblacksud]

It’s a Sud box so it’s mechanical drive.

[Spacenut]

There is an internal circlip holding the speedo drive in the casing. You can get it out without the correct circlip pliers, but re-fitting it is another matter!

Once the clip is removed, there should be a gap in the casting that should allow the drive to be carefully tapped out with a small drift/screwdriver. I managed it on my Gold Cloverleaf gearbox, but my original '78 Ti box had been exposed to the elements for too long and the drive had corroded in place - this can happen because the outer sleeve of the speedo drive is mild steel and the gearbox casing is aluminium

You can't remove the RH drive flange/halfshaft until the speedo drive is out of the way.

As others have said, the plastic gear on the end of the drive is prone to cracking and can fail. A brass replacement is the answer, if you can find one. Good luck!

Lauren

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Thank you Lauren.

I’ll have a practice on one of the spare gearboxes I have to perfect my technique! I can be a bit ham-fisted at times.

Adam

[Spacenut]

Thank you Lauren.

I’ll have a practice on one of the spare gearboxes I have to perfect my technique! I can be a bit ham-fisted at times.

Adam

Good idea Adam - doing it for the first time on your road car can be a bit daunting, especially if that steel sleeve puts up a fight!

Lauren

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The speedo issue was resolved, the gauge end of the cable was rounded and would not drive the mechanism so I swapped it for a spare. Unfortunately the spare was rounded at the gearbox end and was binding in the sheath causing it to pull out.

Its great that we can now buy original spec. parts from the Sudshop in the UK and they came to out rescue and we now have a functioning speedo.

We took the car to a track day at Keevil airfield on Friday 29th April and it ran faultlessly and more than kept up with some much more modern and powerful stuff.

Here's a photo from Friday

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So far this year my son has taken part with the red 33 in four races as part of the Castle Combe Hot Hatch challenge, which was going well until the crankshaft broke in the last race on August bank holiday Monday.

He noticed that the HRDC has a classic Alfa Challenge race on Sunday 22nd and so we are going to enter that in the Sud whilst we get the 33 sorted.

He has lapped the Sud around Castle Combe in around 1 minute 21s on track days in the past in dry conditions and is a demon in the wet (unlike me) so we should be able to mix it with the more experienced racers.

Thanks Adam