Cam Swap before and after results
06-03-2013, 10:33 AM
#1
Cam Swap before and after results Some of you in this section may know this customer of mine as NXZ28 or by his real name of Don. Don is stationed in Germany and has a 4th gen F-body with a 416 c.i. stroker motor that he likes to race a lot when military life and the weather permit him so. Don contacted me way back in January of the beginning of this year for a new camshaft that would perform as best as it possibly could on nitrous. He felt his old cam was lazy, and was causing his combination to under perform. I was tasked with fixing this issue.
Don's combination is as follows:
416 CU (4.070" bore x 4" stroke) Approx 11.5 to 1 compression
AFR 225cc 72cc heads.
PRC EHT 675" lift springs set at .006 coil bind
Comp Endure X solid lifters
T&D 1.7 shaft mounted rockers
2" primary with 3.5" collector headers
Super Victor EFI intake
Accufab 4500 Throttle body
Holley 50# injectors
A very solid combination for sure that has the potential to run very quick even with a full weight 3600lb. carcass to drag around. Don's old camshaft was ground on what I consider lobes that are "older technology". While they do work, and work well...there have been major advancements in lobe technology over the years.
The major issue here was the AFR spring pockets will not accommodate a large enough diameter spring to run anything more than about .675"-.700" valve lift with less than desirable seat and open pressure. This complicated things in the sense that I could not run the lobes I normally do in applications like Don's. This necessitated some out of the box thinking, but I quickly came up with a very solid lobe profile that I found deep in the corners of the comp catalog haha.
Make no mistake this cam was ground with one thing in mind and that was a 400 shot. Don had currently been spraying a 200 shot with a best E.T. of 10.25@131 1.45 60' and was able to run 10.90-11.00@123-124 consistently on motor. When Don first installed the cam and took it to the track, he began shifting the new cam at the same RPM he shifted the old camshaft. Around 6900rpm or so. He lost .5 tenths of E.T. and 7mph with the new camshaft versus the old camshaft on motor which had him fairly upset and wondering how he was going to gain what he had lost back when nitrous was being used. I reassured him that the cam needed to be shifted at least around 7400-7500rpm and that it would improve drastically on motor and on nitrous once this was done. With renewed vigor Don set out the next week(this last weekend) to try again. The only reason he was unable to spray it on his first outing was rain. He had the bottle warmed up and everything, but was unable to make a pass on nitrous.
Fast forward to this last weekend and Don makes it to the track. With a 7500rpm shift point set, and the window switches off point raised to go along with the higher shift points Don was ready. Shifting the car at 7500rpm picked him up 2 mph in the 1/4, but he still has lost 5mph on motor compared to his old cam. Gained .1 tenth from the higher shift point as well so we're at a loss of .4 tenths now. Don did mention that the "track"(old airport runway with 10 years of rubber as traction compound) was garbage that day and everyone was having issues with traction. He feels he can get another tenth out of it on motor on a better day.
On to what really matters! Don finally loaded up the 200 shot, and made some passes. When the smoke cleared Don laid down a 9.87@135 with the new camshaft! That's a gain of .4 tenths and 4 mph over the old cam on the same amount of nitrous! The best part about it, on this pass Don hit the 7700rpm window switch at about the 1000' mark so he didn't have nitrous for the last 200-300'! On top of that, Don's 60' on his previous best 10.25@131 was a 1.45, his 9.87@135 pass it was a 1.54! Needless to say there is at least a tenth hiding in the E.T. from a better 60' and possibly 2-3 more mph and another tenth on the big end from the nitrous cutting off.
This just goes to show how much a cam that is suited for nitrous will run over a cam that is not. I will say that a true nitrous cam is not for the weekend enthusiast, it's not for someone that will not be spraying nitrous all the time. As you can see Don lost a ton of E.T. and MPH on motor. This is mainly from the much larger cam profile he has now versus the old cam profile. He would need a much looser stall converter than he has now to gain the E.T. and MPH lost back on motor. Nitrous performance would suffer if Don changed the stall. I cannot wait until the 300 shot and 400 shot jets are loaded up and to put this thing in the 8's at full weight!
Sorry for the long post guys, but I feel that track results are much more telling than dyno numbers. I can say that it takes good power and torque to run fast at the track, and if you make big power on the dyno you can just about rest assured it will put up big numbers at the track. That said, when your results come from the track I feel it speaks larger volumes than on the dyno. Yes the weather was probably different than when he ran the last time, but it's quite apparent where the gains came from in this situation. Don feels that his converter is causing a lot of slip or possibly the transmission. He did change from a TH350 to a TH400 before he swapped cams, as he thought he was having transmission issues which may of been the converter all along.
Here's a video of the 9.87@135 pass, note how loose Don's converter is as you can barely hear the 2-3 shift extension as he goes down track. Also you can hear the nitrous cut off as well. Enjoy!
Don's combination is as follows:
416 CU (4.070" bore x 4" stroke) Approx 11.5 to 1 compression
AFR 225cc 72cc heads.
PRC EHT 675" lift springs set at .006 coil bind
Comp Endure X solid lifters
T&D 1.7 shaft mounted rockers
2" primary with 3.5" collector headers
Super Victor EFI intake
Accufab 4500 Throttle body
Holley 50# injectors
A very solid combination for sure that has the potential to run very quick even with a full weight 3600lb. carcass to drag around. Don's old camshaft was ground on what I consider lobes that are "older technology". While they do work, and work well...there have been major advancements in lobe technology over the years.
The major issue here was the AFR spring pockets will not accommodate a large enough diameter spring to run anything more than about .675"-.700" valve lift with less than desirable seat and open pressure. This complicated things in the sense that I could not run the lobes I normally do in applications like Don's. This necessitated some out of the box thinking, but I quickly came up with a very solid lobe profile that I found deep in the corners of the comp catalog haha.
Make no mistake this cam was ground with one thing in mind and that was a 400 shot. Don had currently been spraying a 200 shot with a best E.T. of 10.25@131 1.45 60' and was able to run 10.90-11.00@123-124 consistently on motor. When Don first installed the cam and took it to the track, he began shifting the new cam at the same RPM he shifted the old camshaft. Around 6900rpm or so. He lost .5 tenths of E.T. and 7mph with the new camshaft versus the old camshaft on motor which had him fairly upset and wondering how he was going to gain what he had lost back when nitrous was being used. I reassured him that the cam needed to be shifted at least around 7400-7500rpm and that it would improve drastically on motor and on nitrous once this was done. With renewed vigor Don set out the next week(this last weekend) to try again. The only reason he was unable to spray it on his first outing was rain. He had the bottle warmed up and everything, but was unable to make a pass on nitrous.
Fast forward to this last weekend and Don makes it to the track. With a 7500rpm shift point set, and the window switches off point raised to go along with the higher shift points Don was ready. Shifting the car at 7500rpm picked him up 2 mph in the 1/4, but he still has lost 5mph on motor compared to his old cam. Gained .1 tenth from the higher shift point as well so we're at a loss of .4 tenths now. Don did mention that the "track"(old airport runway with 10 years of rubber as traction compound) was garbage that day and everyone was having issues with traction. He feels he can get another tenth out of it on motor on a better day.
On to what really matters! Don finally loaded up the 200 shot, and made some passes. When the smoke cleared Don laid down a 9.87@135 with the new camshaft! That's a gain of .4 tenths and 4 mph over the old cam on the same amount of nitrous! The best part about it, on this pass Don hit the 7700rpm window switch at about the 1000' mark so he didn't have nitrous for the last 200-300'! On top of that, Don's 60' on his previous best 10.25@131 was a 1.45, his 9.87@135 pass it was a 1.54! Needless to say there is at least a tenth hiding in the E.T. from a better 60' and possibly 2-3 more mph and another tenth on the big end from the nitrous cutting off.
This just goes to show how much a cam that is suited for nitrous will run over a cam that is not. I will say that a true nitrous cam is not for the weekend enthusiast, it's not for someone that will not be spraying nitrous all the time. As you can see Don lost a ton of E.T. and MPH on motor. This is mainly from the much larger cam profile he has now versus the old cam profile. He would need a much looser stall converter than he has now to gain the E.T. and MPH lost back on motor. Nitrous performance would suffer if Don changed the stall. I cannot wait until the 300 shot and 400 shot jets are loaded up and to put this thing in the 8's at full weight!
Sorry for the long post guys, but I feel that track results are much more telling than dyno numbers. I can say that it takes good power and torque to run fast at the track, and if you make big power on the dyno you can just about rest assured it will put up big numbers at the track. That said, when your results come from the track I feel it speaks larger volumes than on the dyno. Yes the weather was probably different than when he ran the last time, but it's quite apparent where the gains came from in this situation. Don feels that his converter is causing a lot of slip or possibly the transmission. He did change from a TH350 to a TH400 before he swapped cams, as he thought he was having transmission issues which may of been the converter all along.
Here's a video of the 9.87@135 pass, note how loose Don's converter is as you can barely hear the 2-3 shift extension as he goes down track. Also you can hear the nitrous cut off as well. Enjoy!
06-03-2013, 02:37 PM
#3
Heavy raceweight and the converter is definitely too loose. The fact that it only picked up 8mph on a 200 shot from what it ran on motor before my cam pretty much shows that the converter is too loose.
This isn't Nick's car that weighs 2900lbs....if it was it'd be going a lot faster. The point is it picked up .4 tenths and 4 mph with a cam swap on the same tune-up and a tenth slower 60' and the nitrous cutting off 300' before the traps. It also only has 11.5:1 compression.
I don't know why you had to make a condescending remark like that Steve, but you damn well know if the nitrous had stayed on for 300' more feet it would of trapped at least 2-3mph higher. Is it the fastest thing out there, no. Did it pick up tremendously with a cam swap? Yes it did.
I was just impressed that a cam swap was able to do what it did in this case.
This isn't Nick's car that weighs 2900lbs....if it was it'd be going a lot faster. The point is it picked up .4 tenths and 4 mph with a cam swap on the same tune-up and a tenth slower 60' and the nitrous cutting off 300' before the traps. It also only has 11.5:1 compression.
I don't know why you had to make a condescending remark like that Steve, but you damn well know if the nitrous had stayed on for 300' more feet it would of trapped at least 2-3mph higher. Is it the fastest thing out there, no. Did it pick up tremendously with a cam swap? Yes it did.
I was just impressed that a cam swap was able to do what it did in this case.
Last edited by Sales@Tick; 06-03-2013 at 02:48 PM.
06-03-2013, 02:48 PM
#4
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Thanks for the write up Martin. I couldn't be more pleased with the gain on the nitrous just from a cam swap. The car has never left that hard and I had the two step turned down to 3300 rpm so it would somewhat hook. Everyone was off 1-2 tenths on their 60 foots. Germany is experiencing some crazy weather this year. The air temp was around 55 degrees and we were battle a nasty crosswind that was gusting up to 25 mph.
@ StrokerTA, The car was pulling 7700rpm through the lights. With a 3.89 gear and 28" tire I was seeing 20-22% converter slip. A new converter will be at the top of my list for next year along with some overdue weight reduction. I think it should trap in the 140+ range.
Thanks again Martin for the awesome cam. I was worried at first with the N/A passes but it comes to life on the spray and the car wanted more timing. I just didn't bring enough nitrous.
@ StrokerTA, The car was pulling 7700rpm through the lights. With a 3.89 gear and 28" tire I was seeing 20-22% converter slip. A new converter will be at the top of my list for next year along with some overdue weight reduction. I think it should trap in the 140+ range.
Thanks again Martin for the awesome cam. I was worried at first with the N/A passes but it comes to life on the spray and the car wanted more timing. I just didn't bring enough nitrous.
06-03-2013, 03:13 PM
#7
Thanks for the write up Martin. I couldn't be more pleased with the gain on the nitrous just from a cam swap. The car has never left that hard and I had the two step turned down to 3300 rpm so it would somewhat hook. Everyone was off 1-2 tenths on their 60 foots. Germany is experiencing some crazy weather this year. The air temp was around 55 degrees and we were battle a nasty crosswind that was gusting up to 25 mph.
@ StrokerTA, The car was pulling 7700rpm through the lights. With a 3.89 gear and 28" tire I was seeing 20-22% converter slip. A new converter will be at the top of my list for next year along with some overdue weight reduction. I think it should trap in the 140+ range.
Thanks again Martin for the awesome cam. I was worried at first with the N/A passes but it comes to life on the spray and the car wanted more timing. I just didn't bring enough nitrous.
@ StrokerTA, The car was pulling 7700rpm through the lights. With a 3.89 gear and 28" tire I was seeing 20-22% converter slip. A new converter will be at the top of my list for next year along with some overdue weight reduction. I think it should trap in the 140+ range.
Thanks again Martin for the awesome cam. I was worried at first with the N/A passes but it comes to life on the spray and the car wanted more timing. I just didn't bring enough nitrous.
You know I respect your opinion and you know I consider you a friend. Don't act like that man. I just took your comment the wrong way...I feel Don and I have some work to do with the car to really have it up to its true potential, but I felt I should share how much a properly specified nitrous cam could pick up over one that wasn't 100% optimal.
It will get there Don! You just get home safe soldier!
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06-05-2013, 12:50 PM
#13
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It was setup more for motor and a small shot. I wanted more from the spray than motor. I decided to go with the nitrous cam because I want to move up over 250hp on the spray. I think the cylinder pressure would have pushed a head gasket with the old cam. It is a night and day difference between the old cam and the new nitrous grind.
06-05-2013, 05:46 PM
#14
It really depends on how often you spray the car and how much. A lot of other factors play into "do I need a nitrous cam or not" such as: how much your cylinder heads exhaust port flows, what the balance of I/E flow % is and many more.
06-05-2013, 08:14 PM
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Plan on spraying everytime at the track but drive it there and back 100 mile round trip. Forged 427 with TFS 235 cnc heads, Fast 102, single noid DP setup dry 26-28 jet. So is that enough info to decide if it needs to be nos specific? On motor it did 9.87 at 135 1.40 60ft footbreak. Shifting at 6700-6800
