nitrous V quench

I am also with Lem on the exhaust side and intake I don't think the intake is the problem cause it's getting it in just not out..... I think you will be ok at .071 just make sure your headers are up to par big tube primary

10SHOTS wrote:

Lem Evans wrote:

10SHOTS wrote:

richter69 wrote:If it were a methanol deal then hyd lock might be an issue........ Also if its lifting the heads the pistons aint gonna live no matter what.

Not a bad idea to add quench and maybe some exh duration...one thing id do when i went back out is pull 5 more degrees and go from there

ok I've talked to my cam guy , and he said the 284-298 114 lobe sep ain't getting the exhaust valve open wary enough , he said the about the same thing Mr. Evans said , said my heads ain't good enough for  350 to 400 shot of spray on a 566 cid motor , he won't to put a 286-305 on a 115.5 installed at 113 and said don't get the compression over 13.5 but he would do 13.1 , do you think he's close on the new cam ?
I was thinking do the cam , 13.5 compression , Pistons .020 in the hole , .051 gaskets
I think he said the the exhaust will open at 92 or 95 degrees I can't remember

I doubt that your 284* intake is much of an issue if any at all. I'm ~ on the same page as your guy relative to the exh. duration and lsa.....304* @ .050" and a wider lsa i.m.o.

he started out with a 283 intake lobe with a 305 ex then changed his mind for some reason

The duration @ .050" tells a story but, not the whole story. A 283* lobe could have 4 * more duration at .200" tappet lift than a given 285* lobe and make more power than the 285* lobe.

What does the exhaust port on a P51 head flow?  What is the intake?

i think it was 260ish after Charlie ported mine, I had Blake go back this last go round and grind the f-ck out of the exh ports.

I have 2 3/8" primarys and 4.5" collectors also.

intake is a Blake the Snake cut and welded TFS "mafia" w two used direct ports

also I see the cam and exh port on the small side limit power out of the bigger nitrous tunes but I doubt its gonna start hurting parts, unless its way off in left field........ Id want the compression brought down though.

10SHOTS wrote:562 has 190

That number tells you a lot. Either make the heads flow more on exhaust of cam the motor to compensate.

richter69 wrote:also I see the cam and exh port on the small side limit power out of the bigger nitrous tunes but I doubt its gonna start hurting parts, unless its way off in left field........ Id want the compression brought down though.

As Jon says, usually just doesn't make anymore power with jet increase not hurt parts.

my exhaust ports are hogged out as well all the way in to the bolt hole and header is a step 2-1/4 2-3/8 in to 4.5 collector.

this is the numbers I have wrote down but may not be exact 285@50 307@50 865 in 845 ex 115 sep.the new cam will change bit I don't know the amount.

Larry T wrote:my exhaust ports are hogged out as well all the way in to the bolt hole and header is a step 2-1/4 2-3/8 in to 4.5 collector.

this is the numbers I have wrote down but may not be exact 285@50 307@50  865 in 845 ex  115 sep.the new cam will change bit I don't know the amount.  

Larry I think your combos biggest problem was the copper gaskets.....JMO

i think bigger headers are next as well.  If it's a straight nitrous deal just go to 2.5" to 5" and be done.

Not only will help the flow but kills a lot of the heat.

richter69 wrote:also I see the cam and exh port on the small side limit power out of the bigger nitrous tunes but I doubt its gonna start hurting parts, unless its way off in left field.....
... Id want the compression brought down though.

what compression ratio would I need to shoot for ?

Lem Evans wrote:

10SHOTS wrote:

Lem Evans wrote:

10SHOTS wrote:

richter69 wrote:If it were a methanol deal then hyd lock might be an issue........ Also if its lifting the heads the pistons aint gonna live no matter what.

Not a bad idea to add quench and maybe some exh duration...one thing id do when i went back out is pull 5 more degrees and go from there

ok I've talked to my cam guy , and he said the 284-298 114 lobe sep ain't getting the exhaust valve open wary enough , he said the about the same thing Mr. Evans said , said my heads ain't good enough for  350 to 400 shot of spray on a 566 cid motor , he won't to put a 286-305 on a 115.5 installed at 113 and said don't get the compression over 13.5 but he would do 13.1 , do you think he's close on the new cam ?
I was thinking do the cam , 13.5 compression , Pistons .020 in the hole , .051 gaskets
I think he said the the exhaust will open at 92 or 95 degrees I can't remember

I doubt that your 284* intake is much of an issue if any at all. I'm ~ on the same page as your guy relative to the exh. duration and lsa.....304* @ .050" and a wider lsa i.m.o.

he started out with a 283 intake lobe with a 305 ex then changed his mind for some reason

The duration @ .050" tells a story but, not the whole story. A 283* lobe could have 4 * more duration at .200" tappet lift than a given 285* lobe and make more power than the 285* lobe.

the 283 lobe is 202 @.200 the 286 lobe is 205 @ .200 , my 284 lobe I have now is 205 @ .200

I think most of the answers have been posted, the moral of the story is every engine will react differently, more nitrous will not necessarily make more power, you can go beyond the sum of the the parts, combination, or tune without the results, every engine will reach maximum efficiency with the given serviceable external parts which are easily changed. If you are looking for an answer that is the end all be all it does not exist, open or closed chambers,quench timing, cam, heck fuel delivery was barely touched upon, if you want a max effort engine that eats copious amounts of the Juice, plan the engine with the engine builder you are comfortable with and don't limit yourself by buying all the parts first.! A dollar saved may be a dollar earned, but a dollar saved on the wrong parts could be the limiting factor. JMO

obviously I am lacking education in the cam department as I have relied on others that know their craft to do this for me.other than the heads the cam seems to be my next area of concern.sabo,conly and others that have run the bbf nos stuff have struggled it looks like they have moved on to what I don't know.

I would like to try the header adapter so I could use the round bbc flange.charlie has talked about the adapter extending the runner and the round bbc flange will or should not hold back the exhaust.

What u have should work..... Imo before i did all that i would have a different set of heads in the works

I was about to buy a set of the profiler heads about 2 years ago.at this time im all in with what i havebesides i cant afford the 10/12000 hit at the moment.

I was about to buy a set of the profiler heads about 2 years ago.at this time im all in with what i havebesides i cant afford the 10/12000 hit at the moment.


STICKY KEYS DAMN IT.........

I talked to comp cams today talked to dean Harvey , told him the engine combination  heads , valve sizes and flow numbers , port runner cc , cubic inch , the whole combo , and that I was going to use a 350 to 400 shot hit ,
he came up with this 285-308 on a 116 installed at 114 , exhaust valve opens at 92

10SHOTS wrote:I talked to comp cams today talked to  dean Harvey , told him the engine combination  heads , valve sizes and flow numbers , port runner cc , cubic inch , the whole combo , and that I was going to use a 350 to 400 shot hit ,
he came up with this 285-308 on a 116 installed at 114 , exhaust valve opens at 92

That's not much smaller than what we spec out. We usually grind it on a 118 but install it at 114 as well. When do your heads back up because I figured it needs to be in the 880-930 lift range depending on that.

whatbumper wrote:

10SHOTS wrote:I talked to comp cams today talked to  dean Harvey , told him the engine combination  heads , valve sizes and flow numbers , port runner cc , cubic inch , the whole combo , and that I was going to use a 350 to 400 shot hit ,
he came up with this 285-308 on a 116 installed at 114 , exhaust valve opens at 92

That's not much smaller than what we spec out.  We usually grind it on a 118 but install it at 114 as well.  When do your heads back up because I figured it needs to be in the 880-930 lift range depending on that.

tfs only gives flow numbers to .800
401-287 @ .800 , THis cam has a 484 lobe lift on the intake and exhaust , the car is 3010 pounds with a 370 gear , I asked about a wider lobe sep . he said he thought the car was to heavy , what's your thoughts ,
I also had a cam company that said , 281-312 on a 118 for a 350 shot ,

Your gonna have fun getting a cam w. .900 of lift to work on that style of head.......


Imo you guys are making all this way too hard.

richter69 wrote:Your gonna have fun getting a cam w. .900 of lift to work on that style of head.......


Imo you guys are making all this way too hard.

that's why I said it the way I did. All of our X customers and Limited customers are in that range very successfully but us dumb ole Texas boys like to over complicate things.

So after reading 7 pages, it sounds like the BBF needs an open combustion chamber popup pistons and better flowing exhaust ports to work better with big shots of N20? Are the water passages around the exhaust ports the problem or the pushrod angle/valve layout or just the combination of it all?

in my opinion it needs a larger closed chamber so you would have an option to have a piston with a raised bump to help with cooling.