Is a cam swap worth the hassle

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racin69z
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Is a cam swap worth the hassle

Post by racin69z »

I have a 3350# 69 Camaro that I drive on the street and do some local hard tire heads up racing with. I have 275/60/15 400 tread wear "Hercules" street tires. I havent raced since 2007 and everyone else has upgraded and I have the same old crap. I am low on power compared to the other cars right now. I am saving and gathering parts for a turbo build but it wont be this year. Right now it has a approx (never ccd the heads for sure )12.5:1 383 with 220cc pro action aluminum heads, Pro tru dome pistons, single plane pro products intake, 1 3/4 hooker super comp headers, 950hp carb. Current cam is a 260 270 @ .050 .660 lift roller on a 106 lobe sep angle installed at a 102 ICL. I am spraying 175hp of nitrous through a big shot as soon as the tires are hooked up, which is usually 2nd and 3rd gears. Best ET is 6.61 1/8. The car has been 6.96 on motor on tires that hook. I am not a super good nitrous tuner, but if I spray more than 175 it will burn the #4 piston down the sides and then the rings stick and it looses compression. I always used 112 octane sunoco gas. 28 degrees total timing. NGK #9 plugs. Considering switching to E85. I also have a water meth kit if thay may help.

I have another cam sat aside for the turbo project that I am considering trying. Its a 244 248 @.050 .640 .630 lift 114 lobe sep angle. I am not a cam wizard, but the wider lobe seperation angle seems to be what alot of people run with nitrous cams so I was wondering if anyone had any thoughts. Or any other thoughts about my combination.

Thanks
Lynn
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Re: Is a cam swap worth the hassle

Post by Walter R. Malik »

racin69z wrote: Sat Apr 04, 2020 11:28 pm I have a 3350# 69 Camaro that I drive on the street and do some local hard tire heads up racing with. I have 275/60/15 400 tread wear "Hercules" street tires. I havent raced since 2007 and everyone else has upgraded and I have the same old crap. I am low on power compared to the other cars right now. I am saving and gathering parts for a turbo build but it wont be this year. Right now it has a approx (never ccd the heads for sure )12.5:1 383 with 220cc pro action aluminum heads, Pro tru dome pistons, single plane pro products intake, 1 3/4 hooker super comp headers, 950hp carb. Current cam is a 260 270 @ .050 .660 lift roller on a 106 lobe sep angle installed at a 102 ICL. I am spraying 175hp of nitrous through a big shot as soon as the tires are hooked up, which is usually 2nd and 3rd gears. Best ET is 6.61 1/8. The car has been 6.96 on motor on tires that hook. I am not a super good nitrous tuner, but if I spray more than 175 it will burn the #4 piston down the sides and then the rings stick and it looses compression. I always used 112 octane sunoco gas. 28 degrees total timing. NGK #9 plugs. Considering switching to E85. I also have a water meth kit if thay may help.

I have another cam sat aside for the turbo project that I am considering trying. Its a 244 248 @.050 .640 .630 lift 114 lobe sep angle. I am not a cam wizard, but the wider lobe seperation angle seems to be what alot of people run with nitrous cams so I was wondering if anyone had any thoughts. Or any other thoughts about my combination.

Thanks
Lynn
You really do need a camshaft change for nitrous. You would need a whole new combination with a turbo kit; especially at 12.5/1 compression ratio.
Get a good quality cam about 264/276@.050" with around .700" net lift and 112 to 114 separation. A supercharger cam would work OK.

Headers are on the small side for nitrous but, fine NA.
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Re: Is a cam swap worth the hassle

Post by lefty o »

id start with good tires. honestly, a good set of modern drag radials.
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Re: Is a cam swap worth the hassle

Post by racin69z »

Thanks for the replies.

I am planning on an entire different engine build for the turbo setup.

The class I am racing is a tire limited class. Must run a 220 or greater treadwear tire. The tire is supposed to be the equalizer, but I am still low on power compared to the other folks.

Lynn
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Re: Is a cam swap worth the hassle

Post by rebelrouser »

I am not a cam guru either but the one thing I see is, if you build an engine set up for nitrous, with a good nitrous cam, you have to use nitrous, to get good performance. A nitrous cam bleeds off too much cylinder pressure for a N/A engine to work good with it. So in your case, a good nitrous cam will kill a lot of low end torque, get you off the starting line, then you could stage in nitrous and make it run down track. Which is the strategy most street racers use as far as I know.

I have a lot of guys ask about building an engine, and when they say I want a nitrous cam because I may want to use nitrous someday, I just say No.

I built an engine for a mud racer who wanted to race two classes, one allowed nitrous and one did not, I told him that any more than a 300 shot would melt the engine with the cam I selected. he did fairly good, but after he decided to only race the nitrous class, we changed cams bumped up the nitrous and it ran too good, they wrecked it four times in one year, most of the time was trying to get it stopped leaving the mud pit, as it went through the pit on the rear wheels, and then goes air borne when it hits the dip at the end of the pit.

I had a buddy that bought a 10.5 nitrous outlaw drag car, 66 Nova that ran high 8's in the quarter, he was kind of scared to turn on the nitrous, so his first couple passes he left it off, as I remember to car never got in the 10's. He even called the guy, all the guy said was you are stupid. First nitrous pass was a 9.10 wheels in the air, and my buddy was shaking like a leaf when he got out of the car.

Just a couple of my experiences.
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Re: Is a cam swap worth the hassle

Post by n2omike »

Walter R. Malik wrote: Sat Apr 04, 2020 11:57 pm You really do need a camshaft change for nitrous. You would need a whole new combination with a turbo kit; especially at 12.5/1 compression ratio.
Get a good quality cam about 264/276@.050" with around .700" net lift and 112 to 114 separation. A supercharger cam would work OK.
And advance it several degrees. The conventional thinking with a nitrous cam, is to keep the intake event pretty much what it would be n/a, but open the exhaust valve sooner, and leave it open a bit longer. This means, making the exhaust lobe bigger, spreading the lobe separation, and advancing it.

More experienced cam experts can add to this, but this is the gist of it. Some also give it a little more intake duration than what they normally would, as nitrous makes more TORQUE than horsepower... which shifts the power range down a little bit.

Again, I don't speak as a cam 'expert' for individual combinations... just providing general info.

Good Luck
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Re: Is a cam swap worth the hassle

Post by MadBill »

n2omike wrote: Sun Apr 05, 2020 1:06 pm... nitrous makes more TORQUE than horsepower... which shifts the power range down a little bit....
A double-edged sword with nitrous is that it directly adds horsepower, regardless of RPM, so for example, a 300 HP shot will add 263 lb-ft. of torque @ 6000 RPM, but if triggered at 3000 RPM, will add 525 lb-ft., to the possible detriment of the block, rotating assembly, etc... #-o
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Re: Is a cam swap worth the hassle

Post by Monza355 »

Are you allowed to use MSD Grid to control the timing ? What’s the tune for your 175 hp shot of nitrous ? 106 lsa cam is not a ðroblem with this amount of nitrous. But i feel the 28 degrees of timing is to much. Have you read the plugs while tuning the nitrous ?
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Re: Is a cam swap worth the hassle

Post by CamKing »

Not only is the cam not correct for NO2, it's also not correct for a limited tire class.
A cam change would be a huge improvement.
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Re: Is a cam swap worth the hassle

Post by racin69z »

It was 2007 when I last raced so the details are fuzzy. If I recall I was spraying 76 jets squared with 6# flowing fuel pressure 950 bottle pressure. The annealing mark on the ground strap of the plug was usually at or near the bend. I tried spraying a larger shot two times, and the #4 piston popped each time. That makes 3 times total for that hole. Its on its last leg! I am not sure why it is taking out the piston. 1.125 CH, or just that they are shelf pistons, or bad tune. I sprayed 325 forever on my 377 till one of the china rods buckled, so I have some experience with larger amounts of spray.

There are no rules that I know of about ignitions. Never heard of the grid. I was setting the timing to the total that I was spraying on (28*), then using a MSD retard box with either a 5* or 8* chip in it to make the car a pig off the line. As soon as the car was settled, I would turn the retard off. Then I would either activate the nitrous manually in first or when I hit second gear with a switch on the shifter. It would run pretty consistent high 6.60's with a best of 6.61 I was the class champion in 2007 and won 5 of 6 races. I had all but one guy covered by 4 tenths. But,, everyone has got faster since then. I want to try a race or two this year, but I don't want to look like a chump.

I really don't have the money right now to throw at it, but I do have the previously mentioned cam stuck back for the turbo build. What little project money I have is going towards the turbo build. I thought if it would allow me to get down the track faster by spraying more down track I would try it. I always felt that once I had the car stuck, I could have put way more power down. I have pop up lifters, so it would be free to swap. If anyone has any other ideas or insight id be glad to hear it.

Lynn
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Re: Is a cam swap worth the hassle

Post by CamKing »

The 244/248 cam you have, is also completely wrong for running NO2 and limited tires.
If you don't have the money for the correct cam, try selling the 260/270 cam to some bracket racer who doesn't run NO2, them try and find something on a wider LSA(112-114) with an intake duration in the 260's, and 10-12 more degrees on the exhaust, and .700"+ lift
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Re: Is a cam swap worth the hassle

Post by n2omike »

CamKing wrote: Tue Apr 07, 2020 11:15 am The 244/248 cam you have, is also completely wrong for running NO2 and limited tires.
If you don't have the money for the correct cam, try selling the 260/270 cam to some bracket racer who doesn't run NO2, them try and find something on a wider LSA(112-114) with an intake duration in the 260's, and 10-12 more degrees on the exhaust, and .700"+ lift
Exactly. The tight LSA will hit far too abruptly to properly hook a small tire, and the cam won't allow you to run much nitrous without hurting the engine. Needs a wider lobe separation/more exhaust duration to both make it more manageable, and to allow it to safely digest an ample amount of nitrous. Listen to Camking, he knows what he's talking about. Will be MUCH happier with a proper cam swap. Good Luck
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Re: Is a cam swap worth the hassle

Post by steve316 »

I agree. Like what Walter suggested & then MIke.
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Re: Is a cam swap worth the hassle

Post by racin69z »

Fellas,

Thanks for the info. That is what I needed to know.

Lynn
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Re: Is a cam swap worth the hassle

Post by GARY C »

racin69z wrote: Tue Apr 07, 2020 9:25 pm Fellas,

Thanks for the info. That is what I needed to know.

Lynn
Can you or do you run a progressive nitrous controller?
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