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That is correct. I had them do a .419 lift with the same duration. Also, with a wider lobe separation.
If I did it again. I would have kept the stock duration, but, increased the lift to about .430. Close lash adjustment would be in order to prevent noise.
As for my cam, it is very good for everything. It's not too temperamental. But, power starts to fall off around 5700 rpm on a loaded dyno. Not the 6000 they advertised. Yet, this is with my increased lobe separation I asked for... And I have no idea what the lobe lift is at .050 lift. Some cams ramp up quicker, therefore, more aggressive. Mine is quite tame. I would have gone more aggressive, but, my piston compression is 9:1, so I would not burn the fuel properly if I went with a more aggressive cam.
My vacuum is ok. But I have no means of measuring it.
My vacuum is ok. But I have no means of measuring it.
When tuning this project you need to know what the vacuum profile is. This is super important at idle, light and part throttle.
Get a vacuum gauge. The MPS influences the fueling considerably. See if adding a few degrees of timing provides a better a vacuum profile at part throttle and thus more accurate fueling.
Do you still have a single coil and stock ignition module, if so you're luck it even make it over 5000 RPM. Consider an crane ignition module and a modern high capacity coil. A v12 going at 6000RPM is like a V8 going at 9000 RPM.. That's a lot to ask of a coil.
i use the Crane X700 computer , had original from 1994, a Advance auto standard hi-output coil! 1978 Pre He , V12, tried the Crane X3000 module,(ran like crap), burnt up the coil, NOT compatible with 12 cylinders, V8 or less only!
my engine will rev past 6500rpm no problem(but not pulling tho). shifts best at 5700/6000rpm! Crane RACE cams, .410lift, new springs from Grp44 racing,shimmed .060 thou. Grp 44 oversize valves single piece forged Stainless steel. 9.2 compression pistons, low drag Moly rings! the usual port/polish modded ports!,, almost forgot, inlet manifolds and plenums completely EXTRUDE HONED, no humps and injector bumps! OS TBS.
i also use a stanalone fuel system SDSEFI.com,, had it since 1994, but as they advanced in technology, they upgraded at NO charge, 1998!
again company owner emailed,around 2006, they were changing there basic systems, and sent back and completely new board(same box and plugs), No charge, just shipping Calgary!
i do like it ,but in beginning a lot of tuning/retuning/and retuning!! learning curve is an UNDERSTATEMENT,, OH Yeah!!
but now i'm pretty sure i got it covered,(i think),LOL. for me i could not be without the mixture control,Lean/rich, and AFR gage!
of course trans and rear gear mods, usual stuff!
probably forgot some stuff,, 26yrs ago build, if i were to do it over , it would be TWIN TURBO, E85/or methanol!
ron
When tuning this project you need to know what the vacuum profile is. This is super important at idle, light and part throttle.
Get a vacuum gauge. The MPS influences the fueling considerably. See if adding a few degrees of timing provides a better a vacuum profile at part throttle and thus more accurate fueling.
Do you still have a single coil and stock ignition module, if so you're luck it even make it over 5000 RPM. Consider an crane ignition module and a modern high capacity coil. A v12 going at 6000RPM is like a V8 going at 9000 RPM.. That's a lot to ask of a coil.
I have upgraded my single coil ignition. I have a Crane xr700, going through a MSD box, with a dry race coil. Yes, I agree, a single coil can't do 6000 rpms. My car on the dyno started to cough out around 4800 rpms with the Crane and MSD box. The MSD liquid coil could not energize and spark fast enough. So, I had to put a race coil in. Fixed the problem. So spark is good.
I still have not gotten a vacuum guage...
I know Norm used single Marelli coils on the race cars which were good for 7500rpm
Two single coils are good. But, one single coil is no good. I experienced this on the dyno. Infact they had to increase the sensitivity of their pick up wire to max, just to get a reading at higher rpms. The spark fizzled out.
No, the cars had 2 coils until the mid 80's. Then the low resistance Ducallier coil came in and was able to charge fast enough to use a single coil. If you use a single coil with a primary resistance under 0.5 ohm it should work fine. In contrast, an older coil for points ignition is about 3 ohms.
No, the cars had 2 coils until the mid 80's. Then the low resistance Ducallier coil came in and was able to charge fast enough to use a single coil. If you use a single coil with a primary resistance under 0.5 ohm it should work fine. In contrast, an older coil for points ignition is about 3 ohms.
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look at my 1st pic , shows a single coil standard Advance auto high output coil, and in the dizzy i use the Crane XR700 optical sensor setup! with my preference for advance curve simple weight/spring setup!
When tuning this project you need to know what the vacuum profile is. This is super important at idle, light and part throttle.
Get a vacuum gauge. The MPS influences the fueling considerably. See if adding a few degrees of timing provides a better a vacuum profile at part throttle and thus more accurate fueling.
Do you still have a single coil and stock ignition module, if so you're luck it even make it over 5000 RPM. Consider an crane ignition module and a modern high capacity coil. A v12 going at 6000RPM is like a V8 going at 9000 RPM.. That's a lot to ask of a coil.
I finally bought a vacuum tester. My car is floats around 18 - 21 Hg. Better than nothing I guess...
So, I had a few months where I redid my interior. The inside looks fantastic! So, I finally got back into tuning...
So, does anyone know if I can increase the higher RPM fuel quantity without effecting the bottom end? So, I need to increase the quantity of fuel at the top end but not the bottom end.
It seems everything that I adjust, directly effects both the top end and bottom end. I need to expand my fuel hump. I increased my fuel pressure. It gives more up top, but it also gives more at the bottom. Which I don't need. So, the top end is good, but the bottom end is rich. I have maxed out the T1 adjustment from AJ6, which adds more to the top end hump. I even have played with the resistor value to get more T1. It seems I maxed out the injector spray timing. I need a bit more... in order to allow my bottom end to run properly with the right A/F mixture.
Right now, the bottom end is running richer in order to get the top end barely safe. It really isn't. If I lean out the bottom end, my top end leans out too.
judging by your setup , you may Have to go standalone adjustable , so as be able to adjust AFR maps from top to bottom , factory ECU are not compatible to your mods!
ron
Ron, you are correct. I re-read some emails long ago from AJ6, Roger Bywater, and he said that. They had to make a special circuit to integrate it with the stock ECU. They did it, but, he did not have time to make one for me... I am trying to not spend $5000 on another computer...
Yes, I have already did this, but because of the lower vacuum I have, it doesn't do it as well. I just read an article about FMU and I can put 2 in a row. I will try this. This would make a good boosted car. lol.
It's a fair bit of work, but you might consider the Megasquirt ECU if you're a DIY type. It would be easier as the car is already injected, all you have to do is the tuning. https://www.diyautotune.com/shop/megasquirt-assembled/
Last time I checked Megasquirt required an extra board to handle 12 cylinders, they had it but I had no time to wrap my head around it. Generally, based on Megasquirt unit one could build a dream ECU, which tunes itself to max economy when cruising and to max power when floored. Must install wide-band O2 sensors for that.
05-14-2019, 11:41 AM
