camshaft rpm vs cubes

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Norway-dart

Norway-dart

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Hi.

If a lets say 240@050 108lobe sep camshaft peaks at 5500rpm in a 408, where do you guess it would peak in a 360?

Cant find any dynopapers with the hughes 3742 i will try to use in my 360.. need to know the peak point to get the head velocity correct. Pipemax tell me lobe-rpm ballpark figure is 5500 with my 360, but if the 408 peaks there im wondering if the 360 would put it much higher?

Have a nice mopar day!
 
I would guestimate it around 5800 based solely on the difference in stroke. Personally I own Pipemax - as long as the head/port info you input is accurate, so will the output. What are the specs on the cam?
 
if pipemax tell me camshaft lobe rpm = 5300, but on dynopapers a 408 peaks at this RPM. who is telling the truth? pipemax or the dyno?



I bought the camshaft some years ago for another project, the new design is 36/42, but my camshaft is 237/242@050 on a 108 lobe sep. .548,.555lift @1.5. me going 1.6.

if you go on hughes homepages, they have some dynotests of a 408 and 416, they both peak in the 5300-5400 area. http://www.hughesengines.com/TechArticles/10408416strokerdynotestingsept2002.php

even if the brake show happy values, peak rpm would be directly connected to the camshaft, right?

Dave @ hughes told me I could break the 400hp goal with this camshaft if the parts are correct, I doubt it if it peaks @ 5000 in my 360. I believe I need at least a 5600 peak. im talking real hp, no westech hp...:D
 
krazykuda said:
Hughes has a 3642, not 3742.

With those specs in a "general" 360 with dual plane intake, peak torque is 3000 RPM, and peak HP is 5000 RPM...
Click to expand...

Im going sheet metal intake with pipemax length and size. injection.
-procomp alu heads ported to meet pipemax flow and size
stock stroke,rods. sp pistons.
 
Norway-dart said:
Im going sheet metal intake with pipemax length and size. injection.
-procomp alu heads ported to meet pipemax flow and size
stock stroke,rods. sp pistons.
Click to expand...


I'm still in the learning curve for the dyno progaam... :banghead:

Not quite sure how to put in numbers to more closely simulate yours. It's hard to predict airflow numbers for custom parts, you usually have to flow test them and enter the specific numbers manually.
 
thanx for the try:) I guess you need a houndred-thousand dollars-programs to be really close is simulating power, because there are ,like you say,so many factors involved:)

but I was mainly searching for the peak rpm, and your program shows 5000. thats interesting. pipemax 3.2 that I have on my computer by larry meaux, peak where I want it, because the peak power is a input value. thats why I really need to be as close as possible, because it change the whole setup regarding to flow,runner length, runner volume etc.

what I lack is experience... I have not built more that a few engines:-(
but thats what the forums are there for:) sharing:)


the hughes engines in the link may have had too large runners, that make the engine peak higher, but maybe they had gotten more power if they had the correct runner size/velocity.
 
An XE268H with 224 at .050 will peak around 5300-5400 in a 360. Put 13* more duration in and it peaks the same, not likely.

I'll guess It will peak around 5700-5900.
 
Good mention Cracked.

To the OP, also remember there are other items that change what happens to the engine.
Bow I list the parts but the parts themselfs can vary a lot and effect the performance of the engine.
Carb size
Intake design
Cylinder heads
Exhaust
Ignition
And how the cam is degreed in the engine will effect how and where the cam performs.

In general the cam grinders will tell you the cam performs in *** range. This is a general range. Adding/decreasing stroke or cylinder bore changes the range a little.
This is where things can get complex in addition to the above list. Most people have. Hard time with it. While I understand it I do not get to deep into it. To explain it on a basic level, every part can have a up or down effect on where the power comes in and how it can be delivered. Getting into the science and mathmatical part of it becomes hard to explain and best read to understand.
 
Jup, i second that, but the thing we all strive for is to get the "combo" correct, this will give you the most horsepower!?? You need to build the engine around the camshaft or else you can not get it optimal. Sure it will run, but you may be way off the best potential.

Crackedback, i think the xe268 has 110 degrees lobe separation, this will widen the powerband and crate the peak higher, but you let of some torq in the middle....
 
If its one thing competing in the EMC for the last 6 years has taught me, it is this. Camshaft timing has very little to do with where the peak power occurs. Primary importance goes to the intake tract. If your induction is great-you can put in a stock cam and have it peak @ 6000+ rpm. Adding more cam timing to a cylinder head limited combo may bump peak power production up a bit (100-300 rpm) but really no more than that. This notion that "cubic inches eats up duration" is entirely warped.Cylinder heads and intake system dictates most of where the powerband winds up. One clue I will divulge is this: LSA determines the engines "personality" NOT duration when it comes to talking cam numbers. J.Rob
 
RAMM said:
One clue I will divulge is this: LSA determines the engines "personality" NOT duration when it comes to talking cam numbers. J.Rob
Click to expand...


I like to look at overlap when comparing cams. Overlap is directly related to LSA; smaller/tighter LSA gives more overlap, larger/wider LSA gives less overlap and less "lopey idle".

If you have low compression, it will help to run a wider LSA for less overlap to increase cylinder pressures.

If you have higher compression, a smaller/tighter LSA will give you less cylinder pressure and may help run lower octane fuels.

Duration sets the power band, overlap helps tune it in for the compression...

I think that they are both important to look at when picking a cam...
 
I will say that you should make 6000 RPM. You are going from a 408 with a 4 inch stroke down to a 360 with a 3.58 stroke. All else being equal, your ability to feed the 360 will be much easier {with the same heads that is}. The LSA sounds like it is very close to optimal for a 360, JMHO.
 
I agree. A 110 is fine
I would do a 108 if it was important enough. Non issue really. It'll go fine ether way.
 
AJ/FormS said:
I really hate to disrupt what looks like the beginnings of a great thread,but I have to ask this: Are you building this engine for competition?
Click to expand...

This is a 99% street engine. saterday night spesial:D we have wery few tracks in norway. maybe some time, I take it to the strip.
 
Okay, a fello streeter .
I had a Hughes HE2330 in my 366 combo once that peaked right around 5300 as measured by the Gtec Pro.
I currently have a Hughes HE3237 cam which seems to peak around 5700.Maybe a hair more or less. So thats about 400rpm for 9* more intake duration. I know it doesnt extrapolate linearly, but another 5*, to 237*, Would put you in the range of 5900 to 6000, as others have mentioned.
The rest of my build is 10.7Scr with KB107s@+.005, alum.Eddies(stock) with 1.6 roller-tipped alum.rockers, AirGap&750Holleydp, and TTIs. Makes enough power to go 93 in the eigth.
IMO this is an excellent street pkg, and it burns the lowest octane gas commonly available; 87E10.
Its behaves just like the stocker, but has twice the hp,and way too much torque for 295/50-15s with street suspension.They will break loose on concrete at up to 50mph,4300rpm,2nd gear(1.92 M/Tx3.55diff), with a stomp on the go-pedal.Learning to negotiate turns at sub-30mph has been in exercise in self-control. 275s were a joke.
 
RAMM said:
If its one thing competing in the EMC for the last 6 years has taught me, it is this. Camshaft timing has very little to do with where the peak power occurs. Primary importance goes to the intake tract. If your induction is great-you can put in a stock cam and have it peak @ 6000+ rpm. Adding more cam timing to a cylinder head limited combo may bump peak power production up a bit (100-300 rpm) but really no more than that. This notion that "cubic inches eats up duration" is entirely warped.Cylinder heads and intake system dictates most of where the powerband winds up. One clue I will divulge is this: LSA determines the engines "personality" NOT duration when it comes to talking cam numbers. J.Rob
Click to expand...

Yeah, but that Stock camshaft peaking that high does have a terrible powerband!?
no power anywhere...?
you may size the intake track to "ram" at a spesific rpm, and I believe if this area falls right in the cams sweet spot, the gains are much more that ramming outside of the optimal area.

it would have been interesting to see a dyno where they have different intake csa(based on wanted peak rpm) on the same camshaft. Wonder how the powerband would have moved around.


My case is that if I set up the intake tract for 5900rpm peak, the port may be too big for the engine Down low, throwing away alot of torq there would make me a looser on the street:burnout:
 
AJ/FormS said:
Okay, a fello streeter .
I had a Hughes HE2330 in my combo once that peaked right around 5300 as measured by the Gtec Pro.
I currently have a Hughes HE3237 cam which seems to peak around 5700.Maybe a hair more or less. So thats about 400rpm for 9* more intake duration. I know it doesnt extrapolate linearly, but another 5*, to 237*, Would put you in the range of 5900 to 6000, as others have mentioned.
The rest of my build is 10.7 Scr, aluminum Eddies(stock) with 1.6 roller-tipped al.rockers ,AirGap/750Holleydp, and TTIs.
Click to expand...

thats Nice info!:) do you have a 360?
lately I have read Magazines that want to show a tight lsa as the "New" trick to make big Power... they seem to peak rather high even With tight lsa, but I Guess some of the rpm capabilities lies in the heads. on a Stock J or x head, the story would have been completely different.
 
RAMM said:
If its one thing competing in the EMC for the last 6 years has taught me, it is this. Camshaft timing has very little to do with where the peak power occurs. Primary importance goes to the intake tract. If your induction is great-you can put in a stock cam and have it peak @ 6000+ rpm. Adding more cam timing to a cylinder head limited combo may bump peak power production up a bit (100-300 rpm) but really no more than that. This notion that "cubic inches eats up duration" is entirely warped.Cylinder heads and intake system dictates most of where the powerband winds up. One clue I will divulge is this: LSA determines the engines "personality" NOT duration when it comes to talking cam numbers. J.Rob
Click to expand...

I think when you're talking compromised packages - or really compromised packages which is really what any street engine is - there is less "warping" then you might hint at. There really is very little in terms of available, bolt on, "perfect" intake tracts when hood clearance, full exhaust, & non-ECM controlled engine management is concerned. Truth be told the fact that you comment only the intake side makes a big impact indicates to me that you're already basing the info on dyno or competition type testing. Yes, exhaust is more a function of blowdown but stil there is a big correlation in peak power and exhaust side tuning. You're not talking about a cruise night 360. Feel free to correct me if I'm wrong - but that's what I take from your comments. So while I agree in theory, I disagree in application here... If that makes sense...lol.
Your run-of-the-mill 408 build will not get the individual development that an EMC engine, or competition engine would. And each one of those has unique parameters you have to fit it into. But, take two piles of parts, bolt them together with one having a 4" stroke, the other having 3.31, or 3.58 as the only non-quality-controlled differences, and they will vary in output rpm based solely on displacement. It's stroke, not bore that can drastically change the environment any camshaft has to work in. It changes the physics of the power application from the chamber to the crank, and the physics of the pressure waves in the intake and exhaust tracts. Now take one example, let's say the 3.58 stroke, and then play with various LSAs and spend some time developing the intake tract & exhaust tracts, and we'd see much more of what you're talking about.
 
RAMM said:
If its one thing competing in the EMC for the last 6 years has taught me, it is this. Camshaft timing has very little to do with where the peak power occurs. Primary importance goes to the intake tract. If your induction is great-you can put in a stock cam and have it peak @ 6000+ rpm. Adding more cam timing to a cylinder head limited combo may bump peak power production up a bit (100-300 rpm) but really no more than that. This notion that "cubic inches eats up duration" is entirely warped.Cylinder heads and intake system dictates most of where the powerband winds up. One clue I will divulge is this: LSA determines the engines "personality" NOT duration when it comes to talking cam numbers. J.Rob
Click to expand...

I would have to agree with it. My first ported heads raised the max rpm from 5800 to 7200. and that was with the same comb except the heads! 340,9.4 compression Mp .474/280 cam.
BUT!!!!!!! THE CAR RAN A FULL SEC SLOWER BECAUSE IT LOST ALL OF ITS BOTTOM END AND WOULDN'T 60 FOOT AT ALL.
 
Cudafever said:
I would have to agree with it. My first ported heads raised the max rpm from 5800 to 7200. and that was with the same comb except the heads! 340,9.4 compression Mp .474/280 cam.
BUT!!!!!!! THE CAR RAN A FULL SEC SLOWER BECAUSE IT LOST ALL OF ITS BOTTOM END AND WOULDN'T 60 FOOT AT ALL.
Click to expand...

"My first ported heads"
 
Cudafever
Are you saying the engine horsepower peaked at 7200?,
Or are you saying the head-flow supported 7200?
Or are you saying you shifted it at 7200?,
Or are you saying at 7201 it was scheduled to blow?
Or other?
lol
 
LOL
I know it sound like a tall tail but it is true. the thing would hardly idle. When i pulled the heads back off there was soot(aka bad reversion)almost up to the top of the manifold.(only had them head on for a couple of months!)

The only common sense i can put to it, is that at the higher rpm the exh started pulling on the intake instead of pollution it.

It acted like a 2 stroke, and when the power would come on, around 4000 rpm, it was alive!

I pulled them head off and had a set of X heads rebuilt and it would only pull to 5800......but it ran a lot quicker and had a nice idle.
 
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