[fofo]

I read a lot about the importance of camshaft specs on a n20 motor.

Here are the specs I have in my 665 BBC with Brodix 15* EPD Heads.

Lift: .864 Intake .864 Exhaust
Duration: .283 Intake .316 Exhaust
Centerline: 116
Manufacturer: CompCams

Cranking compression is about 180#.

I routinely spray 1 stage 34N26F. I also have 2nd stage 36N28F (and will have 3rd stage Punisher from SJ soon).

Thx for the comments.

 

[onefast68]

as good as that motor runs i wouldnt change anything....it is gonna fly on 3 kits..i havent seen very many cars that run as fast as yours on 1 kit with a small jet.

 

[fofo]

Thx Will.

My Body & Paint guy should have the '69 Camaro Front Cap & Hood finished by next week. I spoke to Steve today, and he should be finished with the Intake with the 3rd stage Punisher next week also. After that I just need to get Charlie to finish up the Intake install & a few other small items, and we'll be back testing the last week of January...already made the gear change to 3.89 from 3.60. We have a local IHRA Nitro Jam race in February, and would like to take the '69 Camaro to SGMP at the end of February to see what it can do on a good track with plenty testing time.

Hope 2011 is good for you!

 

[onefast68]

2011 will be a great year fofo..got alot my small stuff done..all that left is to freshen up the transmission and restall the converter .,,the goal is the same as always but i think i will run some 4.80's this year...i would also like to run over 180 as well.

 

[NOS-Nelson]

I read a lot about the importance of camshaft specs on a n20 motor.

Here are the specs I have in my 665 BBC with Brodix 15* EPD Heads.

Lift: .864 Intake .864 Exhaust
Duration: .283 Intake .316 Exhaust
Centerline: 116
Manufacturer: CompCams

Cranking compression is about 180#.

I routinely spray 1 stage 34N26F. I also have 2nd stage 36N28F (and will have 3rd stage Punisher from SJ soon).

Thx for the comments.

Not used to seeing such a huge difference in duration. What is the opening at? 283° on the intake is kind of small.

 

[onefast68]

here are my specs for comparison.

288/314 at .050
int lift 515 ex lift 510 w/1.7 rocker lift is int .875 ex .867
timing events
int open 28 ex open 93
int close 80 ex close 41

cam is on a 116

installed at 114

cranking compression is 175

 

[NOS-Nelson]

here are my specs for comparison.

288/314 at .050
int lift 515 ex lift 510 w/1.7 rocker lift is int .875 ex .867
timing events
int open 28 ex open 93
int close 80 ex close 41

cam is on a 116

installed at 114

32° seems to be the somewhat magic opening for a nitrous engine. Have you ever tried advancing it 2 more degrees?

 

[Monte Smith]

Not used to seeing such a huge difference in duration. What is the opening at? 283° on the intake is kind of small.

I agree with Nelson here.......sure thats not a typo fofo. Is it supposed to be 288 on the intake?

Monte

 

[onefast68]

32° seems to be the somewhat magic opening for a nitrous engine. Have you ever tried advancing it 2 more degrees?

yes and it didnt run as good..it was at 112 for 3 years...i just upgraded to a tunnel ram and bullet said to put it in a 114..i gained 7mph with these 2 changes..and dropped over 3tenths..these are on motor..will spray it next time out..i dont expect those gains on the bottle but if i could get 1tenth and 3mph over my best before on the bottle then it was worth it.

 

[NOS-Nelson]

yes and it didnt run as good..it was at 112 for 3 years...i just upgraded to a tunnel ram and bullet said to put it in a 114..i gained 7mph with these 2 changes..and dropped over 3tenths..these are on motor..will spray it next time out..i dont expect those gains on the bottle but if i could get 1tenth and 3mph over my best before on the bottle then it was worth it.

That isn't a fair comparrison with changing the manifold.

 

[onefast68]

That isn't a fair comparrison with changing the manifold.

true..but the numbers it ran i could not go back to the single carb..ran a 8.76 at 157.7 with a nitrous motor.LOL..i couldnt be happier...i am ready to turn the kits on now.

 

[NOS-Nelson]

true..but the numbers it ran i could not go back to the single carb..ran a 8.76 at 157.7 with a nitrous motor.LOL..i couldnt be happier...i am ready to turn the kits on now.

Of course not. The true test would be to play with cam timing with the nitrous on.

 

[fofo]

Thx for the comments. I did not buy this camshaft, but rather bought the 665 already built & fresh with the camshaft installed (USA Racing Engines, Houston did the engine build originally). I do not have the cam card but the specs I quoted came from the seller. It is NOT a 4/7 swap. USA's invoice sheet reflected that the "Cam was degreed 113 at 7* retard on the Jesel."

It seems to work O.K. & was built (again acording to the notes from the seller & engine builder) for heavy n20 use. The block is a solid aluminum Keith Black piece with water going only through the EPD Heads.

 

[598nos]

Heres a BBC 100% nitrous cam (standard journal) if anyone interested. used one weekend. It was to big for my heads.

 

[Jp outlaw]

Thx Will.

My Body & Paint guy should have the '69 Camaro Front Cap & Hood finished by next week. I spoke to Steve today, and he should be finished with the Intake with the 3rd stage Punisher next week also. After that I just need to get Charlie to finish up the Intake install & a few other small items, and we'll be back testing the last week of January...already made the gear change to 3.89 from 3.60. We have a local IHRA Nitro Jam race in February, and would like to take the '69 Camaro to SGMP at the end of February to see what it can do on a good track with plenty testing time.

Hope 2011 is good for you!

Just a thought -

That's a lot of gear if you're putting the 33-w's back on. Power Mad took a 3.60 out and put a 3.90 back in and went faster all around than he had before; he shifts at 7600 and just lets it pull out the back.

 

[dfree383]

Not used to seeing such a huge difference in duration. What is the opening at? 283° on the intake is kind of small.

got to look at the .200 numbers, alot of the newer cams are getting shorter seat timing but fatter in the middle....

 

[fofo]

JP, I'm confused about your statement about a "lot of gear". You stated that David went faster when he went from 3.60 to 3.90, and I'm similarly going from 3.60 to 3.89, and we both have the same tire height (33"). I shift at the same 7600 he does. The difference is that I am heavier at 3050# AND I run a Glide with a 1.80 1st while he runs a Rossler 3 speed with a 2.10 1st.

Please explain.

NOSNelson, thanks. I do not have the cam card, but I can only assume the 283 Duration is at .050.

 

[NOS-Nelson]

The cam should have a grind number on it. Next time the engine is down call Comp with that number and get a new cam card.

 

[fofo]

Back on Camshaft thoughts...

Here is the specs on my 582 18* Big Duke in the '71 Camaro;

Manufacturer: Comp Cams
Part #: 11-741-9
Grind #: 314RXH-15
Valve Setting: .024 .026
RPM: 5000 to 9000
Duration @ .050: 281 Intake 300 Exhaust
Lift: .839 Intake .800 Exhaust
LSA: 115

With my 1.80 Rockers, that puts tjhe Lift on the Intake @ .888 & .847 on the Exhaust.

The only thing I see from my limited knowledge is that it seems the Exhaust Duration could be higher for heavy n20 use.

Again, comments are appreciated.

 

[another69camaro]

Back on Camshaft thoughts...

Here is the specs on my 582 18* Big Duke in the '71 Camaro;

Manufacturer: Comp Cams
Part #: 11-741-9
Grind #: 314RXH-15
Valve Setting: .024 .026
RPM: 5000 to 9000
Duration @ .050: 281 Intake 300 Exhaust
Lift: .839 Intake .800 Exhaust
LSA: 115

With my 1.80 Rockers, that puts tjhe Lift on the Intake @ .888 & .847 on the Exhaust.

The only thing I see from my limited knowledge is that it seems the Exhaust Duration could be higher for heavy n20 use.

Again, comments are appreciated.

yeah your right that ex duration looks real low for your combo. its lower than every cam i had in my conv head 598 and big chief motor i see run more than conv.