Apocolipse

Tuning was fairly easy but I attribute that to the Halltech 103 maf forward design - keeps the pulses away from the maf sensor which will cause surge. Idle there is not enough overlap to give a false lean like more agressive cams - my bet is that it is right on the edge as it is very easy to pull a little fuel and have it misfire. Cruise areas I am on stock timing map.

I idle at 900rpm with a more agressive spark correction vs stock.

Not sure if the +4 made a huge difference down low but I certainly love the powerband. I am close to 12:1 cr and the reduced torque down low (from cam events vs stock) allows me to put it to the ground easier now than before coming out of corners at track and on street. Powerband starts to hit hard around 4000 rpm and Torque peak is at 48-5800rpm. It then reduces from there but carries strong through to 7200+ giving ~600whp (~440tq) Its not a torque monster but sure carries well into the high rpm. I have fuel cutoff at 7500rpm.

MickVette

Thank you! Great information for me to compare. My current 232/246, .639/.639, 115+3, 9° overlap camshaft is violent when you stab the throttle killing the tires just cruising along in 1st. I'm willing to give up some of that low rpm torque to balance the power delivery and pull harder at high rpms.

I have the Halltech 103mm and I was able to tune out the minor surge it had. When I built my own forced air intake using most of the Halltech 103, surge was pretty aggressive. I was able to tune further and tame the surge, but am currently considering the Halltech MF108 in hopes of softening the air "signal" so I can keep some form of my forced air intake with a larger overlap camshaft.

I also have fuel cutoff at 7500 and idle is at 925rpms.

MickVette

Got oil analysis results today. Wondering if I should do the bottom end. What would you guys do?

Apocolipse

Nope - run it till she blows 😁

MickVette

Thanks for your analytical response. LOL

Apocolipse

You are most welcome haha Over the years I have learned not to fix what isnt broken. Worst case it gets worse and you need a rebuild...best case nothing happens! So may as well chance it.

MickVette

I already have the heads off and rebuilt as well as a cam change, motor mounts etc. I'm already this far so if these numbers are questionable this is a good time for a fresh short block.

The lead has me worried. I'm more of a preventative maintenance type then the run to failure type.

MickVette

I replaced the blurry pic of the Blackstone Labs report a few posts up with a picture you can actually see the numbers (sorry about that). I was concerned with lead being 10 with only 1300 miles on the oil. Heads are currently off the car and I was preparing for a camshaft, oil pump, timing chain and balancer replacement. I will pull the engine, break it down and inspect the bearings, rods and other internals while I'm in there.

AzDave47

Probably the best thing to do with that much already done. Good luck, hopefully you will not find any problems.

Innovate

Good thread and informative, interesting how the K501 has greater lift than the other 2 cams and they are all within 2/2 of each other. As a car with a big cam, yes you lose the lower RPM torque a little bit (I still make big torque though). around 38-4k RPM's the car becomes a ballistic missle. I still spin at low RPM's though.

Also curious about the GT21 cam with the huge lift, I have heard those are bad for our cars with stock rockers.

MickVette

I found some limitations of the version DeskTop Dyno version that I have (cheapest one). I plugged in all the values of known camshaft with dyno chart and "fine tuned" the program to make the dyno charts match best as possible when I started comparing camshafts. As I started comparing more and more camshafts outside of the sizes I was looking at I found the program doesn't really take into account for lift and duration accurately when comparing with known dyno charts. The program does look at LSA a lot more accurately but I must admit the calculations I performed on the DeskTop Dyno are not accurate. It was a fun tool to play with but I guess I needed to spring for the more expensive version.

Your camshaft has 29° of overlap if I saw correctly. WOW!!! How was tuning and highway cruising? I like the fact you can still spin the tires at low rpms and 38-4k rpms coming to life is pretty sweet not like a 5500 on/off switch like a 2-stroke power band. At what rpm does power start to fall off?

I am still deciding which camshafts I want to try depending on how difficult changing them will be with a 2 piece timing cover I recently ordered. I have been working with Stave from CamMotion and he has been great. They will pretty much build anything we can dream up. I started building a spreadsheet to compare driving impressions with different lifts, duration and LSAs. I know there is a lot more to camshaft characterization than that and I already need a 3 dimensional chart to loosely accurately view the differences. I am willing to give up some low rpm torque to spread the power into the mid 7000 rpm range. A lot will depend what I find when I pull the short block apart which direction this project takes and how my tuning skills are as I step up into bigger overlap camshafts.

I saw the GT21 camshaft and was wondering the same thing. That is one of the camshafts I plugged into the DeskTop Dyno and knew the results didn't properly reflect that camshaft. I can't even imagine the loads on stock rockers with that much lift.

STL Mike

Why do guys cut fuel at 7500 instead of spark? HP tuner limitation?

MickVette

You can choose spark if you want. The factory program looks like this so I guess most follow the factory way of controlling the rpm.

MickVette

Traction control uses spark:

jayyyw

I run a 243/258 .660 114+3 camshaft. Makes great power and drives fine. Peaks at 7200 rpm with a Holley Hi Ram. Made 646/555 on a dynapak dyno. I've been able to spin the tires in second gear, around 5-10mph, and smacking the throttle. This cam has 22.5 degrees of overlap.

I will be moving to a 263/275 .666 115 camshaft with 39 degrees of overlap. Should move my peak up over 7500rpms and make huge power in the mid-upper range.

I'd definitely stay away from that GT camshaft. It has an absurd amount of lift for no reason and older, harsh, lobes.

STL Mike

Cutting fuel for a rev limiter seems like an easy way to lean out a motor at high RPM, no? If the ecu can handle the spark management, why not just use that?

jayyyw

Cant lean out the motor if there is no fuel to burn.

MickVette

Your 243/258 cam sound like a fun driver. What was the idle rpm? Could it cruise in 6th? Did you have to drive around the rpm range where most healthy cammed LS7s surge at lower speeds?
The 263/275 is a HEALTHY bump in camshaft size! That is going to be a blast to drive and make some nice power!
The GT was a nice comparison cam and gives a good idea how much piston to valve clearance is there.
Kinda stinks I moved away from Austin. It would be cool to see your set up.

Innovate

Highway driving with my cam is not bad, driving at all anywhere is not bad other than the new Mantic being a pain as I am not used to it yet haha.

My cam is 248/262 .651/.646 113+3. Power starts to fall off after 66-6700 RPM's. I have not been back on a dyno after the new mods and clutch so I have no idea now. I also have the car apart replacing lifters and going Cometic .040 HG's to bump compression to 12:1. Then the car with get tuned and I will strap her on the dyno then.

If your program does not account for lift, I would definitely take results with a grain of salt. Lift matters.

jayyyw

It drives okay. We haven't really ironed out all the drivability on it. I don't really care how it drives. I mainly only bring the car out to race. How it drives on the street makes no difference to me. That being said, you can get it to drive very well. I can use 6th at around 70-75mph. I don't because of the drone in that range.