Guys,
Why is my car peaking at 5700 rpm???? It should peak at more than 6000 rpm.
What is this a sign of ? A restriction on the exhaust or intake side?
Also the dyno shop didn't have a fan. Darn!
BTW I picked up 7 wbhp by going up to 24.5 degrees BTDC at 5700rpm from 23.5 degrees. And another 3 bhp from 12:1 A/F to 12.4:1 A/F.
Next time at the dyno, I'm gonna go with 25.5 deg. adv. and 12.8:1 A/F. I hope to get around 185 wbhp.
Last run was 178 wbhp. But the dyno shop didn't have a fan so I just called it quits.
Hi Zamani,
My experience on the dyno shows the existing air supply used by the 164 engine with original AFM and ducting to be adequate for the job. My engine comes up to standard specs for 200 flywheel bhp @6250. Exhaust air sampling indicates correct mixture which confirms intake characteristics.
What limited the power going higher is the exhaust system which is pretty much standard (by intent) because it is a road use car to keep it civil-especially when I go touring with it over many thousands of kilometers at a time.
So what I am saying is, you need to check the exhaust gas analysis to see what's happening with the burn ie. too rich, too lean, spot on? If it is correct, then obviously you have an exhaust restriction and you need to start there.
Hope that helps.
My experience on the dyno shows the existing air supply used by the 164 engine with original AFM and ducting to be adequate for the job. My engine comes up to standard specs for 200 flywheel bhp @6250. Exhaust air sampling indicates correct mixture which confirms intake characteristics.
What limited the power going higher is the exhaust system which is pretty much standard (by intent) because it is a road use car to keep it civil-especially when I go touring with it over many thousands of kilometers at a time.
So what I am saying is, you need to check the exhaust gas analysis to see what's happening with the burn ie. too rich, too lean, spot on? If it is correct, then obviously you have an exhaust restriction and you need to start there.
Hope that helps.
Transaxle Alfas Haul More Arse
MD,
200 bhp sounds good. Is it a QV?
So by my estimation, 178 wbhp is about 214 flywheel bhp (17% loss factor for RWD). So it looks promising as the engine isn't fully tuned.
Right now the A/F is quite steady from 4K-6K, around 12.2:1 - 12:4:1. Hate to boast, but I've seldom seen "chips" with this steady of an A/F ratio.
Beninca says, a little leaner may get me more horses. OK next dyno session will verify this.
So about the exhaust, mine is as follows
SZ headers/extractors (1.5" ID primaries about 12" length for the longest, and 8" for the shortest)
2" OD downpipe (about 16" length)
Merge collector 2 X 2" in 2.5" out (volume...hmmm about 3/4 litre)
Mitsubishi EVO 6 2.5" cat converter
2.5" OD pipe into 2.25" over axle pipe
straight through 2.25" muffler
2" exhaust tip with S bend (for noise suppression)
Although I don't understand why if the A/F is correct is a sign of exhaust restriction?
200 bhp sounds good. Is it a QV?
So by my estimation, 178 wbhp is about 214 flywheel bhp (17% loss factor for RWD). So it looks promising as the engine isn't fully tuned.
Right now the A/F is quite steady from 4K-6K, around 12.2:1 - 12:4:1. Hate to boast, but I've seldom seen "chips" with this steady of an A/F ratio.
Beninca says, a little leaner may get me more horses. OK next dyno session will verify this.
So about the exhaust, mine is as follows
SZ headers/extractors (1.5" ID primaries about 12" length for the longest, and 8" for the shortest)
2" OD downpipe (about 16" length)
Merge collector 2 X 2" in 2.5" out (volume...hmmm about 3/4 litre)
Mitsubishi EVO 6 2.5" cat converter
2.5" OD pipe into 2.25" over axle pipe
straight through 2.25" muffler
2" exhaust tip with S bend (for noise suppression)
Although I don't understand why if the A/F is correct is a sign of exhaust restriction?
Last edited by Zamani on Tue May 31, 2005 2:04 pm, edited 1 time in total.
Performance
Zamani
It is a standard 164 engine 12v
"Although I don't understand why if the A/F is correct is a sign of exhaust restriction"
What this means is that the intake fuel characteristics that the engine needs are being met and there is nothing you can do here.
It also means that the amount of waste gases being produced are impeding the production of more power due to back pressure.
Incidentally, it is an Americanism to refer to the first stage of exhaust pipes as "headers". This is a shame because these suckers are very important for road or racing and the word headers doesn't say much.
We use the term "extractors" because if they are made correctly, they actually will assist with extraction of gases. The emphasis is on the word correctly.(Sorry about the lecture). If they are made correctly, they will have a tuned resonance. Your primary pipes appear to be the the right OD but should be of equal length. This is bad because all the pipes have a different resonance . For a broad torque, I would suggest about 18 inches minimum.
I am pleased to see you haven't been tempted by the addage "bigger is better" for your OD. Smaller pipes increase velocity and increased velocity produces higher negative pressure behind it which simply put, causes the hot gases to suck the intake stuff in harder resulting in a better intake charge.. blah blah.
There is more if you wanna hear it.
It is a standard 164 engine 12v
"Although I don't understand why if the A/F is correct is a sign of exhaust restriction"
What this means is that the intake fuel characteristics that the engine needs are being met and there is nothing you can do here.
It also means that the amount of waste gases being produced are impeding the production of more power due to back pressure.
Incidentally, it is an Americanism to refer to the first stage of exhaust pipes as "headers". This is a shame because these suckers are very important for road or racing and the word headers doesn't say much.
We use the term "extractors" because if they are made correctly, they actually will assist with extraction of gases. The emphasis is on the word correctly.(Sorry about the lecture). If they are made correctly, they will have a tuned resonance. Your primary pipes appear to be the the right OD but should be of equal length. This is bad because all the pipes have a different resonance . For a broad torque, I would suggest about 18 inches minimum.
I am pleased to see you haven't been tempted by the addage "bigger is better" for your OD. Smaller pipes increase velocity and increased velocity produces higher negative pressure behind it which simply put, causes the hot gases to suck the intake stuff in harder resulting in a better intake charge.. blah blah.
There is more if you wanna hear it.
Last edited by MD on Wed Jun 01, 2005 12:42 am, edited 2 times in total.
Transaxle Alfas Haul More Arse
What do you mean 24.5* ignition, you're not using static advance are you? I thought you had Autronic?
What kind of mufflers/silencers? Absorption? Reflection?
Walk us through the intake system, what does it look like?
What kind of mufflers/silencers? Absorption? Reflection?
Walk us through the intake system, what does it look like?
Mats Strandberg
-Scuderia Rosso- Now burned to the ground...
-onemanracing.com-
-Strandberg.photography-
GTV 2000 -77 - Died in the fire.
155 V6 Sport -96 - Sold!
-Scuderia Rosso- Now burned to the ground...
-onemanracing.com-
-Strandberg.photography-
GTV 2000 -77 - Died in the fire.
155 V6 Sport -96 - Sold!
Actually I will need to get some hard data, like some pressure test at the beginning of the mouth of the air filter and inside the plenum.
Then I need to ask JimK, what's the max potential of the 3.0 12V heads since you can generally predict max power for the heads given the cam specs and flow figures.
I guess exhaust is next, but I'm totally unaware of how to check for restrictions there, except for what MD has said earlier on.
Anyway I will return with some more data.
Where's JimK anyway...too busy at AlfaBB, or interviewing playmates?
Then I need to ask JimK, what's the max potential of the 3.0 12V heads since you can generally predict max power for the heads given the cam specs and flow figures.
I guess exhaust is next, but I'm totally unaware of how to check for restrictions there, except for what MD has said earlier on.
Anyway I will return with some more data.
Where's JimK anyway...too busy at AlfaBB, or interviewing playmates?
Well Z, the greek goblin is back, deluded but alive, heheh!! I must confess the interviews didn't go too well, only one Playmate showed up....Miss March 1964... 
That did it! Short PR career, MD can take over (age hint, hahah!)
Power potential of the heads is what I'm playing with these days (ok guys, I heard that!!). With stock runners or what? Stock runners will give you no more than about 228hp with everything else optimized, which is never the case!!! (Right Vince?). Large runners and/or valves, we'll soon see (hey, what am I doing, I'm trying to write a book here! If you piece all this shiit together why bother?
)
Anyway you cut it, it looks like the engine needs Carillos to make power reliably where it can and this general range is 6500-7500 depending on mods.
Jim K.
That did it! Short PR career, MD can take over (age hint, hahah!)
Power potential of the heads is what I'm playing with these days (ok guys, I heard that!!). With stock runners or what? Stock runners will give you no more than about 228hp with everything else optimized, which is never the case!!! (Right Vince?). Large runners and/or valves, we'll soon see (hey, what am I doing, I'm trying to write a book here! If you piece all this shiit together why bother?
) Anyway you cut it, it looks like the engine needs Carillos to make power reliably where it can and this general range is 6500-7500 depending on mods.
Jim K.
Jim,Use the new 24v gta rods-If they can stay together at 8000rpm on a 24v(with a heavier 101.6mm piston)they will do well on the older engines...
Zman,How come you only running 23/24 deg ignotion??Im up at 28/30 degrees .Have you treid going for more and if so, what were the results??You have a super efficient combustion chamber there!!!
Zman,How come you only running 23/24 deg ignotion??Im up at 28/30 degrees .Have you treid going for more and if so, what were the results??You have a super efficient combustion chamber there!!!
French cars are shit and shit expensive to service and bloody awful and unreliable and expensive and friends don't let friends drive french cars and you wait years for parts.
JimK,
Looks like I'm not too far off. I got bigger runners too, but not too big of course. My target is around 230 bhp at 6500 rpm. I'm not too worried about the stock rods up to 7K rpm on occasions.
Baz,
I'll try 28 degrees next time. Need to find a decent dyno place first, one with a powerful fan that makes Hurricane Sally look like...uh.. Sally.
Actually, do the CSC extractors make a difference in peak power? Compared to the SZ exhaust manifolds that is.
Looks like I'm not too far off. I got bigger runners too, but not too big of course. My target is around 230 bhp at 6500 rpm. I'm not too worried about the stock rods up to 7K rpm on occasions.
Baz,
I'll try 28 degrees next time. Need to find a decent dyno place first, one with a powerful fan that makes Hurricane Sally look like...uh.. Sally.
Actually, do the CSC extractors make a difference in peak power? Compared to the SZ exhaust manifolds that is.
Hey Barry, last time I looked, 3,2 motors and rods don't grow on trees here (like in SA!) A used 3,2 goes upwards from 3500Euros and new rods are 110Euros each (less than I thought actually, hmmm 
!) You have given me something to think about-owing more money to my parts store! 
Z, looks like the damn 3liters can take all the advance you can throw at them! I would hit the dyno with a trick distributor, starting with 25-30 static and 38-40 final! Within 3-4 runs you'll know where its at.
Jim K.
A used 3,2 goes upwards from 3500Euros and new rods are 110Euros each (less than I thought actually, hmmm !) You have given me something to think about-owing more money to my parts store! Z, looks like the damn 3liters can take all the advance you can throw at them! I would hit the dyno with a trick distributor, starting with 25-30 static and 38-40 final! Within 3-4 runs you'll know where its at.
Jim K.
Jim,ran 34 -36 deg on my 3.0l and it feels like a lot of torque,but its actually slower....Ran at kyalami with 34 deg and the motor sounded gruff......came back and retarted to 28 and she`s sweet.My Haltech has 2x pots -1x ignition and 1x for fuel trim.Lovely to play with-a long term tuning tool.Now that I have the Innovate wb lambda with data logging,I can use the road as my dyno -and I do-hence the speeding citations Ive just recieved.....damn....
Zman,do you have a pot for adjusting on the run??Easy to see if your motor will be happy with more ign.Cant remember if Autronic has the feature.......
Barry
Zman,do you have a pot for adjusting on the run??Easy to see if your motor will be happy with more ign.Cant remember if Autronic has the feature.......
Barry
French cars are shit and shit expensive to service and bloody awful and unreliable and expensive and friends don't let friends drive french cars and you wait years for parts.