Zamani: I use 37deg on my 3,0.
Jarle
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junglejustice
- Verde
- Posts: 624
- Joined: Fri Nov 26, 2004 1:19 am
- Location: Granolaville, WA
Zamani, I would guess that the 5700 is measured by the dyno counter and not your tach...?
Any way, 28 degrees seems to be the 12 valve target under full load for max power. (Had this conversation with Domingos (GoTech) a week or so prior and his maps too seem to all like 28 degrees avance at full load!)
Any way, 28 degrees seems to be the 12 valve target under full load for max power. (Had this conversation with Domingos (GoTech) a week or so prior and his maps too seem to all like 28 degrees avance at full load!)
...to Alfa, or not to Alfa? That is the question...
Z
In the GTV-6 factory handbook (uk) it shows 31 degrees maximum advance. "M" mark on the pulley??
And 6/8 degrees static @ 800/1000 rpm
So I guess your safe with "up to" 31 degrees.
just play around on the dyno with 3 or 4 small changes to full load max advance power runs, and see what gives you the most bhp - overlay each run to see what works. Say 28-29-30-31 degrees, and see if the power starts to fall off at 31.
Try to run with setting just before power falls away. Were you runninng with high octane fuel in the tank?? was the tank full ??
In the GTV-6 factory handbook (uk) it shows 31 degrees maximum advance. "M" mark on the pulley??
And 6/8 degrees static @ 800/1000 rpm
So I guess your safe with "up to" 31 degrees.
just play around on the dyno with 3 or 4 small changes to full load max advance power runs, and see what gives you the most bhp - overlay each run to see what works. Say 28-29-30-31 degrees, and see if the power starts to fall off at 31.
Try to run with setting just before power falls away. Were you runninng with high octane fuel in the tank?? was the tank full ??
Andrew b
I have a little comment to make re. the best advance curve for a 3liter, something I've said before: With 11:1 CR, I am using the stock Motronic advance curve (from the ECU map) and performance is very satisfying. The only problem is you have no way of ever measuring the actual advance, not even at idle, because everything varies continuously (idle speed is adjusted by the idle bypass step-motor and primarily by varying the advance). Consequently, when you observe idle timing with a timing light, you may well see a blur-nothing is wrong. Then, if you raise rpm with the throttle, you may see 45-50* at 1500-2500rpm,because of no load! This Motronic is an ingenious thing, I have a long-standing respect for Bosch.
All this does, is illustrate exactly the 3-D ignition map concept. You may have 10* at 2000rpm when going uphill in one case and 45* at no load for example. May sound reasonable like this, but developing a similar system and taking into account temperatures and fuel quality is an engineering feat.
Jim K.
All this does, is illustrate exactly the 3-D ignition map concept. You may have 10* at 2000rpm when going uphill in one case and 45* at no load for example. May sound reasonable like this, but developing a similar system and taking into account temperatures and fuel quality is an engineering feat.
Jim K.
Zman,You can of course retard the overall cam setup to move the power band up in the rev range.It takes away from the bottom end by simply moving the torque band higher.......What are the timing specs for your cams??
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.
Yo Z, if we talk Potenziato or S cams as you call them, I dynoed my car with them and max power is at 6000, max torque at 5000, with CSC headers+free flow. AR says the Pot. power is at 6000 and max torque at 4500, not too far off from our results. I suspect though they're BSíng as usual and the actual torque rpm is more in line with my (and other people's) measurements.
Z, the shop I measured my 75 at, says that my wheel 186hp is 202 engine hp, hence the number I quote from time to time.
Where do you get 17% loss? Usually its around 7% and thats what dyno mfr literature talks about. Another very important point linked to this, is that all chassis dyno makers go to great lengths to explain that any comparison between chassis dyno results is pointless! These instruments must only be used for relative measurements of before and after mod evaluation and even this is questionable, depending on a lot of variables (air temp+humidity, barometric pressure, water+oil temp etc). To make a point, a couple of days after my measurement, I went to another dyno, getting...192 engine hp (177 wheel hp)!!! Disappointing? Psychologically yes, but would things be better if I saw 210 wheel? The car logs almost the same laptimes (and even there we have lots of variables), so I believe that there's no way we can compare results here. About the best we can do is compare the rpm where events occur (to get back to your question).
Your rpm does seem low (assuming cams are timed std) and I can't think of any reason. As MD says, an exhaust restriction would do it-have you ever measured back-pressure? (I have welded 2 little nipples in front of each muffler, to make sure there is no restriction in the exhaust system).
MD talked about the 164 Q engine. Well MD, thats what I have, complete with its -130 ECU and large afm. Then, I have mildly ported heads, 11:1, CSC, everything balanced, clearanced and 215psi compressionx6! All this gives the above power...you figure it out, AR claims 200hp for the stock engine, hardeharhar!
Once and for all, chassis dynos read bonkers!
Jim K.
Z, the shop I measured my 75 at, says that my wheel 186hp is 202 engine hp, hence the number I quote from time to time.
Where do you get 17% loss? Usually its around 7% and thats what dyno mfr literature talks about. Another very important point linked to this, is that all chassis dyno makers go to great lengths to explain that any comparison between chassis dyno results is pointless! These instruments must only be used for relative measurements of before and after mod evaluation and even this is questionable, depending on a lot of variables (air temp+humidity, barometric pressure, water+oil temp etc). To make a point, a couple of days after my measurement, I went to another dyno, getting...192 engine hp (177 wheel hp)!!! Disappointing? Psychologically yes, but would things be better if I saw 210 wheel? The car logs almost the same laptimes (and even there we have lots of variables), so I believe that there's no way we can compare results here. About the best we can do is compare the rpm where events occur (to get back to your question).
Your rpm does seem low (assuming cams are timed std) and I can't think of any reason. As MD says, an exhaust restriction would do it-have you ever measured back-pressure? (I have welded 2 little nipples in front of each muffler, to make sure there is no restriction in the exhaust system).
MD talked about the 164 Q engine. Well MD, thats what I have, complete with its -130 ECU and large afm. Then, I have mildly ported heads, 11:1, CSC, everything balanced, clearanced and 215psi compressionx6! All this gives the above power...you figure it out, AR claims 200hp for the stock engine, hardeharhar!
Once and for all, chassis dynos read bonkers!
Jim K.
JimK,
Talked to a few tuners and they concur with the % of loss. If we take the 7% loss figure, gosh, we won't only have disappointed Alfa owners. And Alfa's aren't the only ones guilty of lying.
I even have a report on 1 car on 5 different dynos (dynojet, mustang, dynapak, DTS). Huge variance. Anyway I'm smart enough to know that comparison between dyno to dyno is pretty useless. But just for laughs.....
Will check on the exhaust restriction though. My outlet pipe is only a single 51mm. Is that too small for an outlet?? Also the SZ exhaust manifold's collector looks a little restrictive.
Talked to a few tuners and they concur with the % of loss. If we take the 7% loss figure, gosh, we won't only have disappointed Alfa owners. And Alfa's aren't the only ones guilty of lying.
I even have a report on 1 car on 5 different dynos (dynojet, mustang, dynapak, DTS). Huge variance. Anyway I'm smart enough to know that comparison between dyno to dyno is pretty useless. But just for laughs.....
Will check on the exhaust restriction though. My outlet pipe is only a single 51mm. Is that too small for an outlet?? Also the SZ exhaust manifold's collector looks a little restrictive.
You confuse me there Z, the lower the loss %, the lower engine power comes out to. 200 wheel with 17% loss becomes 234 engine. With 7% loss, becomes 214 engine hp. As you know, there is no way of realistically measuring driveline loss or even calculating it with reasonable accuracy. A dyno guy (friend) I talked to, said that higher losses is a good way to boost business....everyone wants to see high power numbers! And the software, allows them to do all kinds of tricks!
Jim k.
Jim k.
The dyno I've used measures power by accelerating and then free rolling. The free rolling power is then "driveline loss" but actually also includes rolling resistance of the rear tires.
Anyway, this loss has been about 13% for all Alfas I've dynoed. (Hey, isn't that nicely just between your figures?)
I don't know how it handles engine inertia. Probably an approximation from a book or something. In 3rd gear this already makes a difference.
Like Jim said. Dyno's are only for tuning. Don't even bother comparing figures from defferent ones.
Anyway, this loss has been about 13% for all Alfas I've dynoed. (Hey, isn't that nicely just between your figures?)
I don't know how it handles engine inertia. Probably an approximation from a book or something. In 3rd gear this already makes a difference.
Like Jim said. Dyno's are only for tuning. Don't even bother comparing figures from defferent ones.