ALFAGTV6.COM

[fedezyl]

Great!!! on the to buy list noww!!!!!

[Jim K]

That's 236 engine power. For comparison on the same dyno, the std 3liter cat engine showed 171hp (from an advertised 184).
The attached 24v flow graph is for a very mild porting job, more of a cleanup (with the guides in place and untouched). For comparison, consider that a fully ported 4cyl M3 head goes to ~175cfm! I would think the Alfa can go to ~160cfm with a proper porting effort. The difference is made up from the bigger BMW valves. Still, a possible 160cfm is good for ~420hp according to Superflow.
Jim K.

[Zamani]

Jim,

Did you discuss about cam profiles in the book? Like ramp, LC, separation, benefits of ramp style etc? Just curious.

Also do you have videos of the 12v? I want to see how lumpy those cams are compared to mine. Mine are pretty aggressive with 11mm of lift. But idle is quite ok.

[Jim K]

There are some cam graphs but no detailed discussion on your topics. There is an explanation of certain cam parameters between two cams of identical characteristics yet very different in performance.
I don't have a video but them Catcams should not be offered as a street cam as far as I'm concerned. Idle has to be ~1000rpm to be stable and I would like ~850rpm. To me, good idle is factory idle. Actually, I'm thinking of going back to Motronic cams and a re-dyno!
Jim K.

[gran turismo]

Jim,

That's great news about your book. Thanks for all of the hard work!

Aren't you using motronic? Do you think the idle instability has anything to do with the flapper syle AFM?

If so maybe one of those aftermarket hot wire AFM's would help.

Jeff

[Jim K]

Its the cams. I have used Motronic all along and this is the first time I have lumpy idle. In my previous engine, I tried Catcams #1030322's without remapping and the thing was a rocket after 4500rpm, but I took them out to return to Motronics (didn't want to pay for remapping!) With the ones in the car now, I may attempt a little back and forth timing, in the hope of improving things. Other than this, these cams are great! I opened it up today side by side from 2nd gear ~3krpm with a fwd gtv 2.0TB with 260hp and surprise-surprise, I was ahead by just a hair all the way to 7krpm in 3rd gear! Man, there was a lot of joking around when we got back to the garage! A 3liter na beating a 2liter TB is not the norm! Mind you, I have the 1.8T gearbox and both cars weigh about the same at ~1400kg.
As far as I'm concerned, Motronic rules. I have also purchased a Dicktator and an Adaptronic ecu, but it looks like they'll stay in the box they came in.
Performance of this 12v engine has really got me wondering about the 24v I have finished and sitting around! I'm trying to get my mechanic to stuff it in his 75 1.8T and I'm close to convincing him! We'll see!
Jim K.

[Zamani]

JK,

I think you should install the adaptronic with the current cams. Then we can see the benefits of not having the flapper. After all you have all the equipment, just need dyno time.

Also you have to remember, you have access to a hot blonde who can remap the motronic (now we know why it's so expensive to remap!!!!), but in a lot of other places, re-programming is actually more difficult than installing a new efi and remapping it on your own.

[Jim K]

I tell you what: You are all welcome to come here for a few days, borrow the car and install ecu's, map it and play with it on your own time and expense! I just don't want to mess with it that much any more! I have the cams and I can change them at home and do anything that doesn't require spending more $$! Installing ecu's means spending considerable time to fabricate/adapt a harness and mapping time...So that's more time and money right there
A hot blond? I could use one right now for warmth! Up to yesterday we were in short sleeves (up to 25*C) and since last night we dropped to 2-3* and its snowing in the suburbs! This morning I had a snowfight with my son (there's no snow on the ground but all cars have snow on them! Damn! I sat outside for 4 hours and overhauled two rear calipers...I D-D-DO NEED THAT B-B-B-B-BLOND!!!
Jim K.

[xrad]

JK: I just bought your first book! nice!...maybe by the time i finish reading it, the 6 book will be out.....

[Jim K]

Regarding cam selection for mild performance and whether idle will be lumpy or not, here's a very informative table from noted cam maker SCHRICK (relatively unknown outside Europe):
Which camshafts are good for Street tuning?
If the vehicle is intended for normal street use,
i.e. with a stable engine idle and the ability
to pass an emissions test (idle to lower rpm
range), it is important to consider a small valve
lift at TDC.
The table gives a guideline for valve lift at TDC.
2 Valve engines with solid lifters 2.3 mm
4 Valve engines with solid lifters 1.5 mm
2 Valve engines with hydraulic lifters 1.9 mm
4 Valve engines with hydraulic lifters 1.1 mm
When these values are exceeded, the engine
idle will become increasingly unstable and the
torque delivery in the lower rpm range will be
noticably weaker.
Camshafts with larger valve durations, and a
resulting higher valve lift at TDC, should only
be considered for racing applications, or when
each cylinder has it`s own butterfly valve i.e. 2
twin-choke carburettors on a 4 cylinder engine.

I had found the above info some time ago but had unfortunately forgotten about it. It clearly explains the lumpy idle of my V6 Catcams, as they have 2.95mm lift @TDC...I now have a good mind to suitably reprofile the other set I have (#1030322) and arrange lobe separation to a bit more than 110* lobe centers. Will think about it...
Jim K.

[gran turismo]

Jim,

I was curious about the Cat Cams 1030321 and 22 so I plotted them in excel using the data on the catacams website. They give you lift at 0.1 mm, 1 mm, lift at tdc and peak lift. I had to add a data point with a faked duration at about 9 mm (0.35") lift to get the profiles to look right.

I also plotted the 164S for comparison.

Anyway, I'm no cam expert but wow, those exhaust lobes are huge! And at 106 and 108 lsa no wonder you have a lumpy idle. They also cut into the power stroke quite a bit which can't be too good for low end torque.

If you reprofile the cams maybe consider a shorter duration exhaust lobe which I have heard will often help low end torque but will not hurt the top end very much. Also you wouldn't need to spread the lobe centers as much to get down to the Shrick recommended lift at TDC. I think you would need at least a 115 degree LSA for either cam.

[Jim K]

On Monday, I went to my cam grinder friend here and that's exactly what we talked about: shortening exhaust duration and generally altering the profiles of the #1030322 cams, since it doesn't look that I'll be using them. The man has possibly thousands of profiles in his data file and we narrowed our search down to those with acceptable lift at TDC, total lift over 11.4mm and LC's from 110-112*. We found some and we'll have a new meeting to compare and select what we think is best. I'm confident we'll find a good solution here.
Jim K.

[Zamani]

Jim

Any chance you could let me have the profile for the Clio Williams Catalyst cam profile (ex/in) ? Will pay you if needed. Going to sell off my GTA cams to go for these cams. Also how do you think it compares with GTA cams?

Merry Xmas!

[Jim K]

I have tried to get a set of GTA cams to measure but so far no luck. Not easy to convince someone to let me take them out of their engine! One of the guys is going to have his engine rebuilt soon, so I'll get my chance.
Why would you want the Williams profile? I can post the graph if you want but what good would it do?
And what's this about paying?? You're too far away for schnitzels and its the wrong time of the year too!
Jim K.

[la_strega_nera]

Going to sell off my GTA cams to go for these cams.

howmuchizzit?