Alfa Pages

[Ben_nz]

Here's the problem.
I've been going to a few track days..
In particular I really enjoyed this one with a group of young guys driving assorted old vehicles: http://picasaweb.google.com/oldschool.co.nz/OldschoolTrackdayNationals07
Everyone had such a blast that another track day was immediately booked for November.
I was pretty much dead even with a bunch of cars, including the BMW 535 (cos it is too heavy and its driver wasn't as awesome as me! ), the Alfa 75 2.0 TS and the Peugeot 205 GTi. But now a lot of people are planning and scheming ways to go faster next time.
So.
My car chatters quietly to itself at the best of times, but this is most pronounced under load between 2000 and 3000rpm - all the clacking seems to intensify or coincide. I suspect/hope it is mostly cam lobe and lifter wear, based on the set of heads I retained from my last engine.
The engine compression is fine.
I have rebuilt carbs, a K&N filter or carb trumpets, and an aftermarket rear muffler (the rest of the exhaust is standard).

What's the best way to get more power?
(I'm not changing the gearbox or suspension)

I'm thinking that if I'm losing valve lift because of audible wear on the camshafts, the best real enhancement would be:

Remove heads
Replace worn camshafts and lifters with standard factory spec items
Skim block/heads to improve compression ratio?
Have basic porting changes made to heads as per http://alfaboxertuning.fws1.com/?
Re-fit heads again

Is this sensible or realistic? Based on what I've read, the above seem like the best 'free lunch' changes which will have minimal trade-off. Anyone know if just the heads (not the block) can be skimmed to boost the compression?

Remember this is a daily-driven road car, I'm stingy, haven't stripped a motor, and I won't be making my 33 into a race car any time soon.
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"Now, all that is left to do ... is wait that something else brokens, to fix up again!"

[rsfruitbat]

Which engine do you have 8V, 16V, 1.5 etc

[stedee]

you can skim the heads but you cant take alot off, i have done those mods off that site including the inlet valve reshaping but tbh at the mo my car seems not so fast but it may be due to a problem such as timing which i am trying to sort out (maybe the vacuum advance) or the throttle bodies are leaking air - i dont know yet but i was expecting my car to go like a rocket but it doesnt, the best way i would try to get more power especially if you have carbs is a rebore, you can bore them to 2 litres, they do it for alfa 33 race cars and i know someone who had a 1850 which went like a rocket.also try and cut down on weight if you can - perhaps go on a diet
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[paulhide]

A good exhaust system can gain you a few horsepower (and a poor one can lose you a few) My red car has normal front and centre with a supersprint backbox, but it is nowhere near as good as the stainless system on my white car.

Stedee-you sure your belts are spot on?
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Owner's Club 33 Registrar. Now from P4 & S2 1.7 QV
http://www.alfa-pages.co.uk/viewtopic.php?t=5188

[Ben_nz]

[stedee]

mines injected and i suspected the injectors werent up to much so i have fitted some calibra 2 litre ones with the fuel pump and a fse powerboost regulator because i thought i should have improved air flow,
paul the belts are bang on, ive checked 3 times, i`m trying to find out how the dizzie timing works from what i can see if you adjust the dizzie somehow it automatically compensates and returns to its own settings - i dont understand how it does this plus does the injection timing work off the flywheel sensor?
i`m going to reseal the throttle bodies and check if the vacuum pipes are blocked that run from the bodies to the black tube thingy apart from that i am runnin out of ideas very quickly
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[paulhide]

Standard headers and the boxer sound is gorgeous. Unfortunately I don't know what the exhaust is except it is 16v bore and was supplied by a guy called Adrian Jardine a few years ago.

Stedee, Yeah, ECU and flywheel sensor determine timing and ECU and airflow meter determine mixture I guess.
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Owner's Club 33 Registrar. Now from P4 & S2 1.7 QV
http://www.alfa-pages.co.uk/viewtopic.php?t=5188

[bobbber]

Oh dear Steve.... I'm sorry to hear you're having problems! Certainly seemed fast enough when you came to visit me. The trees in my garden are still bent away from the road from the wind rush after you zoomed past them!

Can I suggest you pop into a Bosch fuel injection specialist? Try to find one with an older bloke who might know a thing or two about the older systems who likes the pack of beer you are going to take with you!

Fuel injection problems are 90% of the time air leak related. Whilst I am the world's leading authority on the LE3 system - I know very little about the Motronic incarnation. Check for air leaks. Check for air leaks.... THEN.... check for air leaks!

Finally, check for air leaks. Common places are in the corrugated elbow after the air flow meter, where it connects both sides, all around the inlet manifold, those (in my opinion daft) rubber pipes which connect the manifold to the heads, even around the injectors seats.

Also - and I don't know if you have some of these on the Motronic system - but any pipes which use vacuum from the inlet to auxiliary components. i.e. the oil segregation pipe, the vacuum pipe to the brake servo, all around the front of the manifold (that stoopid idle regulator valve thingy - all the pipes and connections to and from that). (Phew!)

Then - there's the crankcase. Because it feeds into the inlet through the oil segregator - any air leaks in the crankcase are leaks which also affect the air measurement. So.... leaks around the oil dip stick, around the oil filler cap, even leaks around the oil sump gasket (careful not to over-tighten those bolts down there.... they are a little fragile!).

Once you have tested all that at least four times... I might start believing it's something else!

Hope that's food for thought !

Bob
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Fiat Bravo 165 Sport

[bobbber]

Almost forgot ! The little vacuum pipe which goes to the distributor (although I don't think you have one of those on the 16v) and the little pipe which connects to the fuel pressure regulator on the end of the fuel injection rail.

Here is the Alfa manual for MoTronic fault checking too (if that helps) : http://www.alfa-restoration.co.uk/ml41.zip

Phew!

Bob
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Fiat Bravo 165 Sport

[paulhide]

Make sure you've got good oil in your rear diff?
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Owner's Club 33 Registrar. Now from P4 & S2 1.7 QV
http://www.alfa-pages.co.uk/viewtopic.php?t=5188

[bobbber]

That's a good point actually Paul.... what does the car rev like when it's not in gear?!

Bob
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Fiat Bravo 165 Sport

[stedee]

nice to hear from u bob, it does have a vacuum to the dizzie btw, i cannot understand how the dizzie can be compensated by the ecu as there are no electronic connections to it, i am going to check for air leaks today, is there an easy way to do this? because i smoke i was going to blow smoke everywhere and look for swirling patterns, will this work?

also i did think about the diff but wouldnt the car engine brake quite dramatically as there would be alot of drag on the diff if the oil was crap

thanx for your help guys.
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[bobbber]

I think you'll find there is an electrical connection to the Dizzy!?!?!?

Either way - it's the supply to the coil that times the spark in this case methinks.

Bob
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Fiat Bravo 165 Sport

[stedee]

oh ok i didnt know that
i thought the coil was always on and that the dizzie did the timing by mechanical means ie running off the flywheel or crank
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[lee16v]

I don't have a vacuum to my dizzy. Is it something they changed on the later models?

Steve, I would have thought that any air leak you have would be minor and blowing smoke on it wouldn't show up. Plus you've got the fan on the alternator creating swirling air anyhow.

[lee16v]

Steve you probably know this as you've had your engine apart but the dizzy is run off the same worm gear that runs the oil pump. The ignition timing is ECU controlled as i found out when trying to adjust it because twisting the dizzy around makes no difference to the running of the car....well it didn't on mine. I set mine up in the same place as the old one and when i encountered poor running on initial start up of the new engine i played around with it to no avail. Turned out the throttles were opening at slightly different times causing it to spit on initial acceleration....a quick adjustment of the linkage solved that one!

[stedee]

yeah lee - mine was doing the same and i have adjusted the chokes on the one bank and it seems to run smoother on light throttle but overall power seems not very good
for instance there is a long road by me on a slight incline and it seems to struggle in 3rd and 4th gears, the revs rise really slowly, i dont want to say how fast it goes but say theoretically it reaches 90mph and thats about it, i`m thinking its a timing issue but i dont know where to look, ive changed the brain still the same
i`m thinking of getting it krypton tuned to at least get a clue of what the problem is.
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[aforalfa]

changed the induction kit, added a little cold air feed, balanced the t/bs and redid belts and tensioners on our 16v recently, my god does it go now...
leaves my 155 2.0 16v for dead

the last 16v i did, that was really slow, i just had it in to tension the belts, and upon checking timing marks, as you do, i couldn't see the T on the flywheel.

needless to say, once it was done, the owner had a beeeg grin on his face driving away

Tis easy to feck up the cam timing on em, so check it, ours also feels like sh1t when the belts need tensioning.

[stedee]

is there an advance of tdc to time the cams to or do you always just time the cams to the t mark ie tdc. mine is running alot better now (i found that the maf sensor itself was touching the little plastic shield so i swapped it for another one and the car seems like its got a bit more torque
i am seriously thinking of fitting a mini supercharger as you can get one for a hundred quid, i`m not sure what to do with the belt for it though because the crank spare pulley is a single wide groove and the supercharger has a wider belt with several grooves. i was hoping somehow to change the pulley on the supercharger so i dont have to mess with the crank pulley.

any ideas?
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[col748]

should be able to change idler pulley on charger easy enough i think, where you getting charger from for 100 notes?
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you can sleep in your car nut you can't race your house

[stedee]

ebay - there are quite alot on there because they buy a mini and opt for the works kit b4 actually getting the car and then they sell the supercharger after only about 5 miles or so.

i was going to either fit it under the engine on the left hand side looking from the front or on the top on the right hand side. i have seen a half done 145 with the supercharger underneath seems easier to route all the pipes etc.
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[col748]

will you need to change compressions if you fit charger?
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you can sleep in your car nut you can't race your house

[stedee]

no if its a small one - that is why i`m going for the mini one, i`ve heard they are ok upto 6 or 7 psi, i have even heard they can be good for your engine , something to do with the extra pressure when the piston changes direction at the compression/ explosion strokes.i think atmospheric pressure is around 12- 13 psi so the charger makes the overall pressure about 20psi.
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[mt]