Alfa Pages Forum Index Alfa Pages
A forum for help with the Alfasud And Alfa 33
 

More power?

 
Post new topic   Reply to topic    Alfa Pages Forum Index -> Boxer Workshop
View previous topic :: View next topic  
Author Message
Ben_nz
Gold Cloverleaf


Joined: 30 Sep 2003
Posts: 575
Location: Auckland, New Zealand

PostPosted: Wed Jul 11, 2007 11:40 am    Post subject: More power? Reply with quote

Here's the problem.
I've been going to a few track days.. Rolling Eyes
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! Cool ), 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.
_________________
"Now, all that is left to do ... is wait that something else brokens, to fix up again!"
Back to top
View user's profile Send private message
rsfruitbat
Alfa Sprint


Joined: 13 Jun 2007
Posts: 241
Location: Kidderminster

PostPosted: Wed Jul 11, 2007 4:58 pm    Post subject: Reply with quote

Which engine do you have 8V, 16V, 1.5 etc
Back to top
View user's profile Send private message
stedee
Alfa 33


Joined: 02 May 2006
Posts: 364
Location: brighouse

PostPosted: Wed Jul 11, 2007 5:46 pm    Post subject: Reply with quote

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
_________________
brum brum
Back to top
View user's profile Send private message
paulhide
P4


Joined: 20 Dec 2003
Posts: 1607
Location: Oh Beautiful Billingham

PostPosted: Wed Jul 11, 2007 8:54 pm    Post subject: Reply with quote

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?
_________________
Owner's Club 33 Registrar. Now from P4 & S2 1.7 QV
http://www.alfa-pages.co.uk/viewtopic.php?t=5188
Back to top
View user's profile Send private message Send e-mail
Ben_nz
Gold Cloverleaf


Joined: 30 Sep 2003
Posts: 575
Location: Auckland, New Zealand

PostPosted: Wed Jul 11, 2007 11:19 pm    Post subject: Reply with quote

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

Oops. Embarassed
I have the 1.7 8V engine.

Stedee, has your car improved at all since before making the modifications?
Do you know if it's necessary to adjust the carbs (jet size or something?) to take the modifications into account?

Paulhide, does your better exhaust system still use the standard headers?
I read about crossover manifolds, and the theory makes sense, but they'd have to be custom-made and apparently they may destroy the characteristic boxer sound and make the car sound more like a conventional straight 4?
_________________
"Now, all that is left to do ... is wait that something else brokens, to fix up again!"
Back to top
View user's profile Send private message
stedee
Alfa 33


Joined: 02 May 2006
Posts: 364
Location: brighouse

PostPosted: Thu Jul 12, 2007 12:23 am    Post subject: Reply with quote

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
_________________
brum brum
Back to top
View user's profile Send private message
paulhide
P4


Joined: 20 Dec 2003
Posts: 1607
Location: Oh Beautiful Billingham

PostPosted: Thu Jul 12, 2007 8:37 am    Post subject: Reply with quote

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.
_________________
Owner's Club 33 Registrar. Now from P4 & S2 1.7 QV
http://www.alfa-pages.co.uk/viewtopic.php?t=5188
Back to top
View user's profile Send private message Send e-mail
bobbber
P4


Joined: 14 May 2003
Posts: 2162
Location: The Greatest Town on Earth - Swadlincote, UK

PostPosted: Thu Jul 12, 2007 10:37 am    Post subject: Reply with quote

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 Laughing - 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 ! Laughing

Bob Cool
_________________
Fiat Bravo 165 Sport
Back to top
View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
bobbber
P4


Joined: 14 May 2003
Posts: 2162
Location: The Greatest Town on Earth - Swadlincote, UK

PostPosted: Thu Jul 12, 2007 10:42 am    Post subject: Reply with quote

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 Cool
_________________
Fiat Bravo 165 Sport


Last edited by bobbber on Thu Jul 12, 2007 10:49 am; edited 1 time in total
Back to top
View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
paulhide
P4


Joined: 20 Dec 2003
Posts: 1607
Location: Oh Beautiful Billingham

PostPosted: Thu Jul 12, 2007 10:49 am    Post subject: Reply with quote

Make sure you've got good oil in your rear diff?
_________________
Owner's Club 33 Registrar. Now from P4 & S2 1.7 QV
http://www.alfa-pages.co.uk/viewtopic.php?t=5188
Back to top
View user's profile Send private message Send e-mail
bobbber
P4


Joined: 14 May 2003
Posts: 2162
Location: The Greatest Town on Earth - Swadlincote, UK

PostPosted: Thu Jul 12, 2007 10:51 am    Post subject: Reply with quote

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

Bob
_________________
Fiat Bravo 165 Sport
Back to top
View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
stedee
Alfa 33


Joined: 02 May 2006
Posts: 364
Location: brighouse

PostPosted: Thu Jul 12, 2007 11:40 am    Post subject: Reply with quote

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.
_________________
brum brum
Back to top
View user's profile Send private message
bobbber
P4


Joined: 14 May 2003
Posts: 2162
Location: The Greatest Town on Earth - Swadlincote, UK

PostPosted: Thu Jul 12, 2007 1:21 pm    Post subject: Reply with quote

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
_________________
Fiat Bravo 165 Sport
Back to top
View user's profile Send private message Send e-mail Visit poster's website MSN Messenger
stedee
Alfa 33


Joined: 02 May 2006
Posts: 364
Location: brighouse

PostPosted: Thu Jul 12, 2007 2:22 pm    Post subject: Reply with quote

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
_________________
brum brum
Back to top
View user's profile Send private message
lee16v
16 Valve


Joined: 29 Jun 2005
Posts: 1429
Location: Devon, UK

PostPosted: Thu Jul 12, 2007 6:05 pm    Post subject: Reply with quote

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.
Back to top
View user's profile Send private message Send e-mail
lee16v
16 Valve


Joined: 29 Jun 2005
Posts: 1429
Location: Devon, UK

PostPosted: Thu Jul 12, 2007 6:19 pm    Post subject: Reply with quote

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!
Back to top
View user's profile Send private message Send e-mail
stedee
Alfa 33


Joined: 02 May 2006
Posts: 364
Location: brighouse

PostPosted: Thu Jul 12, 2007 11:27 pm    Post subject: Reply with quote

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.
_________________
brum brum
Back to top
View user's profile Send private message
aforalfa
Alfasud


Joined: 05 Jun 2007
Posts: 77
Location: under someone elses alfa i expect :roll:

PostPosted: Fri Jul 20, 2007 11:24 am    Post subject: Reply with quote

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 Shocked

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 Very Happy

Tis easy to feck up the cam timing on em, so check it, ours also feels like sh1t when the belts need tensioning.
Back to top
View user's profile Send private message
stedee
Alfa 33


Joined: 02 May 2006
Posts: 364
Location: brighouse

PostPosted: Fri Jul 20, 2007 5:37 pm    Post subject: Reply with quote

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?
_________________
brum brum
Back to top
View user's profile Send private message
col748
Alfa Arna


Joined: 14 Aug 2006
Posts: 19

PostPosted: Mon Jul 23, 2007 7:47 pm    Post subject: Reply with quote

should be able to change idler pulley on charger easy enough i think, where you getting charger from for 100 notes?
_________________
you can sleep in your car nut you can't race your house
Back to top
View user's profile Send private message
stedee
Alfa 33


Joined: 02 May 2006
Posts: 364
Location: brighouse

PostPosted: Mon Jul 23, 2007 8:39 pm    Post subject: Reply with quote

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.
_________________
brum brum
Back to top
View user's profile Send private message
col748
Alfa Arna


Joined: 14 Aug 2006
Posts: 19

PostPosted: Tue Jul 24, 2007 7:45 pm    Post subject: Reply with quote

will you need to change compressions if you fit charger?
_________________
you can sleep in your car nut you can't race your house
Back to top
View user's profile Send private message
stedee
Alfa 33


Joined: 02 May 2006
Posts: 364
Location: brighouse

PostPosted: Tue Jul 24, 2007 7:57 pm    Post subject: Reply with quote

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.
_________________
brum brum
Back to top
View user's profile Send private message
mt
Alfa Sprint


Joined: 19 May 2005
Posts: 177
Location: Portsmouth

PostPosted: Sat Aug 18, 2007 1:57 pm    Post subject: Reply with quote

aforalfa wrote:
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 Very Happy

Just spotted this, was that me perchance? Very Happy
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Alfa Pages Forum Index -> Boxer Workshop All times are GMT + 1 Hour
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum