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Re: Quench vs. C/R vs. Fuel octaine [Re: patrick] #502180
10/21/09 11:38 AM
10/21/09 11:38 AM
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Chi_Town_Runner Offline OP
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Patyrick,

Very interesting.

Here is a link to the cam I was LOOKING at, not yet purchased any. Cam Spec Link

I will keep looking at cam profiles to see where I need to go.

Keep the info commin.
I only want to do this once.

Frank


Remember - 2 wrongs don't make a right - but 3 rights make a left!
Re: Quench vs. C/R vs. Fuel octaine [Re: Chi_Town_Runner] #502181
10/21/09 12:21 PM
10/21/09 12:21 PM
Joined: Jan 2003
Posts: 16,122
Grand Haven, MI
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those numbers given for cam timing are .050 numbers.

intake opens 6 degrees BTDC, closes 38 after. 6+180+38=224.

intake installed centerline is 106 ATDC, or 74 BBDC.

1/2 of 224 is 112. 112-74= 38. to figure out advertised ICP, just take 1/2 of 274, (137) and subtract 74 137-74=63.

can't really build compression until the valve is closed, so IMHO the .006 ICP is a better indicator than the .050 ICP + 15 degrees....

for instance, just in hydraulic roller lobe profiles,
look here: http://bulletcams.com/Masters/HRlobes.htm

for 226@.050 lobes, bullet has 10 different profiles with .006 duration ranging from 276 to 293, which assuming the lobes are symmetrical, would mean a .006" intake close point 8.5 degrees later for the 293 over the 276....these lobes also have an 18 degree range (133 to 151) of .2" lift duration.


1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
Re: Quench vs. C/R vs. Fuel octaine [Re: patrick] #502182
10/21/09 12:55 PM
10/21/09 12:55 PM
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Baltimore/Denver
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Quote:

you get
8.2 DCR, using the KB method nets 8.8....it should run fine on 92 or 93, you may have to be a little conservative with your distributor's timing curve.




Does this number take into account his altitude? If not, he's going to end up with a DCR of about 6.5 and a SCR in the high 7s.

And, I don't like the cam... the ramps are too slow for a roller. Get something in the 35º range using the .050" numbers.

ETA: I did some rough calcs using 60º as the ICA, a 10.5 SCR and 6000' of altitude. Your cranking pressure is only 140 psi. That's not going to get it done, Frank.

Last edited by 64Post; 10/21/09 01:10 PM.
Re: Quench vs. C/R vs. Fuel octaine [Re: 64Post] #502183
10/21/09 01:46 PM
10/21/09 01:46 PM
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Chi_Town_Runner Offline OP
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Patrick & 64 Post and anyone else who is not as mathematically challenged as I,

What are your suggestions?

Frank


Remember - 2 wrongs don't make a right - but 3 rights make a left!
Re: Quench vs. C/R vs. Fuel octaine [Re: 64Post] #502184
10/21/09 02:08 PM
10/21/09 02:08 PM
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Grand Haven, MI
patrick Offline
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Quote:

Quote:

you get
8.2 DCR, using the KB method nets 8.8....it should run fine on 92 or 93, you may have to be a little conservative with your distributor's timing curve.




Does this number take into account his altitude? If not, he's going to end up with a DCR of about 6.5 and a SCR in the high 7s.

And, I don't like the cam... the ramps are too slow for a roller. Get something in the 35º range using the .050" numbers.

ETA: I did some rough calcs using 60º as the ICA, a 10.5 SCR and 6000' of altitude. Your cranking pressure is only 140 psi. That's not going to get it done, Frank.




no, I just plugged the IVC point in the calculator. the calculator doesn't account for altitude/air pressure...either way, the compression RATIO is the same, it's just the CYLINDER PRESSURE that's lower at altitude.

also, you can't judge a cam's aggressiveness just by the advertised and .050 numbers. Hydraulic rollers a lot of time "look" less aggressive becasue they usually have slowish opening ramps.

for comparison, let's compare this cam to some hydraulic flat tappets, looking in the comp cams master lobe guide

the comp XE274's intake:

274@.006" dur, 230@.050 dur, 143@.2" dur, .325" lobe lift.

the XE275HL's intake lobe has these specs:

275@.006" dur, 231@.050 dur, 149@.2" dur, .35" lobe lift.

it looks like the cam he's looking at is using comp's XFI lobes, which are amongst the most aggressive hydraulic roller lobes I've seen, and which according to the catalog spec like this for the intake:

274@.006" dur, 224@.050 dur, 149@.2" dur, .358" lobe lift



so for a given .006 duration, the roller has 6 & 7 degrees less than the .842/.904 dia flat tappet lobe, but 6 degrees more, and the same .2" duration, and more lift than both....I'd say that's an aggressive lobe.

lets compare to some solids. can't directly compare advertised numbers, since comp uses .015" lift duration as advertised duration for solids. let's compare to a .842" dia XE solid lobe, which looks like this:

rated dur (.015" lift), .050 dur, .2 dur, lobe lift

262/224/135/.319"
274/236/147/.335"

so it looks like the juice roller's lobe is more aggressive than an aggressive .842" solid flat tappet lobes in terms of .2" dur and lift compared to .050 duration......


1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
Re: Quench vs. C/R vs. Fuel octaine [Re: Chi_Town_Runner] #502185
10/21/09 02:23 PM
10/21/09 02:23 PM
Joined: Jan 2003
Posts: 16,122
Grand Haven, MI
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Quote:

Patrick & 64 Post and anyone else who is not as mathematically challenged as I,

What are your suggestions?

Frank




you are fine. should make a great street motor, should be strong from 1500-5500 RPM. I'd expect the power to peak below 6K RPM. it probably will run on 89, will definitely run on premium.

there's guys with KB107 equipped 360 shortblocks and magnum heads with tight quench (~10.6:1 comp, with iron heads) running comp XE268's and running on premium, can get by with 89 without an overly aggressive dizzy timing curve.

granted, the smaller bore helps slightly with detonation resistance, too...

anecdotally, a friend has a stroker LT1 in his impala SS, 396", with a 230@.050 duration comp hydraulic roller (probably in the 280 adv range), and 11.7:1 measured static compression, and he runs ok on pump premium. it's a little finicky, as the computer sometimes pulls a little timing out on warm days if he fills up anywhere but the shell station that sells 93 octane....

plugging the numbers in on his combo to the K-B DCR calculator, I get a DCR of 9.4-10 depending on using .006 vs. .050+ 15 ICP....granted he has better fuel/spark control running a EFI....


1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
Re: Quench vs. C/R vs. Fuel octaine [Re: patrick] #502186
10/21/09 06:22 PM
10/21/09 06:22 PM
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Aurora Colorado
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I've been watching this post with interest. You all are correct in the choice of cam. Hyd. Roller profiles are more aggresive than a solid ft. However, I think the post while valid, isn't going after the most important item :: cyl pressure. It is very difficult to develop needed cyl. press. The planned motor, w/o the cam is suspect to me. Static compression ratio needs to go up. With alu. heads to 12 to 1.
I had an iron headed 383 at 11.7 static cr and moderately aggressive cam with quench @ .040 that ran w/o any detonation. But it was still underpowered up here.
Consider that we lose an average of .9 sec on a good day of quarter mile times because of air density/cylinder pressure when compared to sea level. Many times our DA is 8000-9000 ft. Generic power loss is on avarage 20%. No cam profile is going to make that much up.
So to plan this out correctly IMHO, Up the static compression ration to 12/1 and .040 quench and use that roller you have posted. My experience says you will still be fine on detonation AND you will have a build that will scream.
I will also add that that cam seams a little small. I've now got a Solid ft that is much more agressive than whats posted in a 470.

Last edited by BELVEDERE67; 10/21/09 06:35 PM.
Re: Quench vs. C/R vs. Fuel octaine [Re: patrick] #502187
10/21/09 06:50 PM
10/21/09 06:50 PM
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Quote:

Quote:

Quote:

you get
8.2 DCR, using the KB method nets 8.8....it should run fine on 92 or 93, you may have to be a little conservative with your distributor's timing curve.




Does this number take into account his altitude? If not, he's going to end up with a DCR of about 6.5 and a SCR in the high 7s.

And, I don't like the cam... the ramps are too slow for a roller. Get something in the 35º range using the .050" numbers.

ETA: I did some rough calcs using 60º as the ICA, a 10.5 SCR and 6000' of altitude. Your cranking pressure is only 140 psi. That's not going to get it done, Frank.




either way, the compression RATIO is the same, it's just the CYLINDER PRESSURE that's lower at altitude.




Exactly! What I'm trying to emphasize here is cylinder pressure is critical at higher altitude. For example, if 165 psi is the limit for 91 pump gas at sea level, then that is the target that should be hit @ 6000'.


Quote:

also, you can't judge a cam's aggressiveness just by the advertised and .050 numbers. Hydraulic rollers a lot of time "look" less aggressive becasue they usually have slowish opening ramps.




I acknowledge rollers are more efficient and do promote higher VE. But, you can't build a 10:1 SCR sea level engine and expect a roller cam alone to make up the 25% loss @ 6000', and we haven't even brought up DA which on some days will be 8,000'-10,000'. Personally I haven't seen any empirical data that quantifies a given percentage increase in VE over a similar solid cam. But let's say there is a 5% increase in cylinder filling using the roller. It still leaves the OP way short on cylinder pressure if he is starting out @ 140psi.

Also DCR is not a panacea. Sure at lower rpm it's a factor, but once the revs go up SCR becomes the dominating factor.

Re: Quench vs. C/R vs. Fuel octaine [Re: BELVEDERE67] #502188
10/21/09 10:24 PM
10/21/09 10:24 PM
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I really do appreciate all the information I'm getting on this.

The 12:1 compression ratio scares me a little. I live at the 6000 ft level but I want to be able to take this car on the road. Any which way I go, N-S-E-W, I decrease my altitude. This car is not going to the track on any regular basis but I will do some traveling with it, so I am willing to sacrafice some HP for drivability at lower altitudes. I guess I'm looking for a compromise that I think has eluded all of us and don't know if it's attainable.

Belvedere67, I listen to your comments with great interest, and respect your input since your in Colorado and have altitude expierence. The only way I can see uping the static C/R at this point is to mill the heads.

Tomorrow, I'm going to the machinist and since the heads aren't in yet we'll just concentrate on the bottom end. I'll go for zero deck and hope to get more input here.

Thanks to all, I'll be standing by.

Frank


Remember - 2 wrongs don't make a right - but 3 rights make a left!
Re: Quench vs. C/R vs. Fuel octaine [Re: Chi_Town_Runner] #502189
10/21/09 10:49 PM
10/21/09 10:49 PM
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Supercharger with several different pulleys (ratios) will fix Ya right up..That is if you have money to burn

Re: Quench vs. C/R vs. Fuel octaine [Re: BELVEDERE67] #502190
10/22/09 02:12 AM
10/22/09 02:12 AM
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Quote:

I've been watching this post with interest. You all are correct in the choice of cam. Hyd. Roller profiles are more aggresive than a solid ft. However, I think the post while valid, isn't going after the most important item :: cyl pressure. It is very difficult to develop needed cyl. press. The planned motor, w/o the cam is suspect to me. Static compression ratio needs to go up. With alu. heads to 12 to 1.
I had an iron headed 383 at 11.7 static cr and moderately aggressive cam with quench @ .040 that ran w/o any detonation. But it was still underpowered up here.
Consider that we lose an average of .9 sec on a good day of quarter mile times because of air density/cylinder pressure when compared to sea level. Many times our DA is 8000-9000 ft. Generic power loss is on avarage 20%. No cam profile is going to make that much up.
So to plan this out correctly IMHO, Up the static compression ration to 12/1 and .040 quench and use that roller you have posted. My experience says you will still be fine on detonation AND you will have a build that will scream.
I will also add that that cam seams a little small. I've now got a Solid ft that is much more agressive than whats posted in a 470.




That is right as the cyl pressure is the bottom line that all of this effects and at sea level I would not push it mover 200 if you want to run on pump. In fact I like to keep it around 180 for pump at sea level. I am not sure at you elevation. But I can say at sea level I would not hesitate to run 11.5 comp with aluminum heads and quench as with the right cam you can run on 92 or 93 pump. My sons 400 has Eddy RPM heads and I cut them to get his 400 at almost 10.8 and it does not have good quench as his pistons are down about .023 and it has the .039 head gaskets. But we run 38 total timing with no ping at all. Aluminum heads can usually run about 1 point higher in comp. But you need to watch where the cyl pressure comes out. A good cam company can help with that. Good luck , Ron

Re: Quench vs. C/R vs. Fuel octaine [Re: 64Post] #502191
10/22/09 02:29 AM
10/22/09 02:29 AM
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Lincoln Nebraska
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Quote:

For example, if 165 psi is the limit for 91 pump gas at sea level, then that is the target that should be hit @ 6000'.


yes if 165 is the limit for 91 inside the cyl(s) it doesn't make any difference if the cyl(s) are located in New Mexico or death valley but since the air outside the cyls is "thinner" at NM you need more CR to squeeze this thin air inside the cyl(s) to get that 165


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Re: Quench vs. C/R vs. Fuel octaine [Re: RapidRobert] #502192
10/22/09 02:47 AM
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Quote:

Quote:

For example, if 165 psi is the limit for 91 pump gas at sea level, then that is the target that should be hit @ 6000'.


yes if 165 is the limit for 91 inside the cyl(s) it doesn't make any difference if the cyl(s) are located in New Mexico or death valley but since the air outside the cyls is "thinner" at NM you need more CR to squeeze this thin air inside the cyl(s) to get that 165




Correct, and that's why we generally add 2 points (maybe more depending on the other usual factors) of static CR to a "sea level" type build and then fine tune the cylinder pressures with the cam shaft. All of the various on line calculators make this a pretty simple task nowadays.

Re: Quench vs. C/R vs. Fuel octaine [Re: 64Post] #502193
10/22/09 03:08 AM
10/22/09 03:08 AM
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64Post do you have a ballpark psi recommendation for me for 87 octane. My daily driver mileage build is coming together & I have not finalized the scr or the cam. Lincoln Nebraska is ~1200 ft & I will be taking no trips


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Re: Quench vs. C/R vs. Fuel octaine [Re: RapidRobert] #502194
10/22/09 10:57 AM
10/22/09 10:57 AM
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Your additional info on how you plan to use that good looking RR does change how aggressive the cam should be.
To answer your question on milling the heads : yes. I used the calculator in this post with your bore and stroke and added a 77 cc combustion chamber with the other provided numbers and came up with 11.3 SCR. I have a set of Eddy's that were milled to 77cc's. Considering that the intake face needs to be milled as well, that may be as much as you can go with a street application. The valve cover rail get a little small for sealing. So, even with the zero deck and the head milling, you still are well below that 12 to 1 number your concerned about. Just to let you know you may not be able the get the compression high enough and be safe in a street app.
You may be spot on with your cam choice even tho it does seem to be a little small. Bear in mind that a stroker motor (this may not be one) does like or eat up cam duration. So this is a consideration for you.......like you need another question..............right?

Last edited by BELVEDERE67; 10/22/09 10:59 AM.
Re: Quench vs. C/R vs. Fuel octaine [Re: RapidRobert] #502195
10/22/09 03:24 PM
10/22/09 03:24 PM
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Quote:

64Post do you have a ballpark psi recommendation for me for 87 octane. My daily driver mileage build is coming together & I have not finalized the scr or the cam. Lincoln Nebraska is ~1200 ft & I will be taking no trips




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