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  #16 (permalink)  
Old 04-18-2006, 11:31 PM
Choctaw Bob's Avatar
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You need to spend the $49 for a Mr. Gasket Desktop Dyno and settle the question once and for all. I go through this everytime I start to design an engine. I always have at least 3 engines and 6 cams I can use because I have them left over from project and I can make more money if I can.
Runn it on the desktop dyno and your questions will be answered.

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Old 04-19-2006, 12:01 AM
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I don't think Desktop is really going to give you any real data, at least I never got any real engineering data out of it. It's fun to play with but it's lacking in any real feedback of information on what's going on with the engine. When we have a question on a build up that needs analysis with some pretty solid engineering behind it we model the engine in EA Pro. In this instance we are really talking about a big block. It's not going to have any trouble make power with a 230cc runner. If your concerned about what it will do at 1000 RPM that's another story.

Here is what your looking for..........
The Intake Runner Velocity 'Int AvgVel' is 323 ft/sec at 6500 RPM with a 230cc runner on that engine which is somewhat high. An ideal 'Int AvgVel' occurs around 5300 RPM, or 260 ft/sec. So, again, your just fine with a 230cc runner given your current cam selection and any future upgrades you may be looking at.

So there is your data. Have fun, that's a nice head.

That Indy head is so superior to the other option it's a no brainer.
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  #18 (permalink)  
Old 04-19-2006, 12:43 AM
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Quote:
Originally Posted by Rick WI
I don't think Desktop is really going to give you any real data, at least I never got any real engineering data out of it. It's fun to play with but it's lacking in any real feedback of information on what's going on with the engine. When we have a question on a build up that needs analysis with some pretty solid engineering behind it we model the engine in EA Pro. In this instance we are really talking about a big block. It's not going to have any trouble make power with a 230cc runner. If your concerned about what it will do at 1000 RPM that's another story.

Here is what your looking for..........
The Intake Runner Velocity 'Int AvgVel' is 323 ft/sec at 6500 RPM with a 230cc runner on that engine which is somewhat high. An ideal 'Int AvgVel' occurs around 5300 RPM, or 260 ft/sec. So, again, your just fine with a 230cc runner given your current cam selection and any future upgrades you may be looking at.

So there is your data. Have fun, that's a nice head.

That Indy head is so superior to the other option it's a no brainer.
I guess if you like to play with data for the sake of data, you can model the data in EA Pro, that is if you don't mind the investment.

With our firm we are more concerned with the effect of off the shelf parts on a client's car. We find we can model the car and predict within 20 or so Hp and a half of a tenth of ET in a quarter by using Dyno 2000 and it's associated software which most of us can afford individually. Since we are more interested in results than theory, I instruct my engineers to invest their time developing packages for specific customers cars and record their time so we can get paid for it. We do have clients ocasionally that are willing to spend the money necessary for R&D in an area where they think they can gain some advantage. But these people also are able to do the R&D themselves but have better things to do with their time. So they make a financial decision to pay us to do the work.
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Old 04-19-2006, 07:07 AM
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Javelin, "got it!" MUCH more clear after your last post.....

not many threads ask: "how can I make my car slower" (and the wife's car quicker with a 224 cam)...thanks for the chuckle!

food for thought(?): use the correct cam and stall, just kill the timing total and spark=slower ET= less chance of detonation with 11/1!!...till you get the roll bar
(now you can adjust "up to" roll bar required)(why make the motor "sick" with a wrong cam on purpose? and buy 2 cams?....still not clear on that part)

general references:
3400lb car, 10.5 ET=580 RWHP (18% loss) 612 FWHP
just pointing out it is not easy to hit 10's with a street car (without a bottle)

loose weight!
3000 lb car 10.5 ET = 512 RWHP

Last edited by red65mustang; 04-19-2006 at 01:02 PM.
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Old 04-19-2006, 08:14 AM
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the first thing anyone who builds a motor needs to do is decide where the engine is going to spend most of its life.will it be a street ,street/strip, strip only ,round track,and be honest with yourself.then you look at the parts you are going to have and decide on the cam and again be honest with yourself because over camming will only hurt you.which side of 100 mph will it spend most of its time on?that should help you decide on the smaller port or larger port and remember that smaller ports move faster air.look at the rest of the edelbrock heads.most are small yet work well.
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  #21 (permalink)  
Old 04-19-2006, 09:38 AM
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Quote:
Originally Posted by GoneNova/406
the first thing anyone who builds a motor needs to do is decide where the engine is going to spend most of its life.will it be a street ,street/strip, strip only ,round track,and be honest with yourself.then you look at the parts you are going to have and decide on the cam and again be honest with yourself because over camming will only hurt you.which side of 100 mph will it spend most of its time on?that should help you decide on the smaller port or larger port and remember that smaller ports move faster air.look at the rest of the edelbrock heads.most are small yet work well.
Best advice on this subject that I have seen in a while.
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  #22 (permalink)  
Old 04-19-2006, 09:53 AM
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Quote:
Originally Posted by red65mustang
y
just pointing out it is not easy to hit 10's with a street car (without a bottle)

l
You really have been to the track working on this! It is tough to make enough HP to pull 3000 pounds that quick, then hook it up, make a drive line work and stay together. You also have to be willing to spend one day a week in preparing the car just to keep it consistant.
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Old 04-19-2006, 10:45 AM
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GoneNova, Choctaw,
he has 2 very nice looking matching Javelins, one (stock) for the street(hers) and one for race(his)

Javelin,
"bracket" race mama with your car....lots of fun....daughter just got a porshe, I coulda/woulda beat her if my reaction time wasn't 1 second (!)....she was ticked (!) when my son beat her with his Suburban mud truck ( he had a hole shot...she did a break out...their still arguing who won)
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  #24 (permalink)  
Old 04-19-2006, 11:00 AM
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Quote:
Originally Posted by red65mustang
GoneNova, Choctaw,
he has 2 very nice looking matching Javelins, one (stock) for the street(hers) and one for race(his)

Javelin,
"bracket" race mama with your car....lots of fun....daughter just got a porshe, I coulda/woulda beat her if my reaction time wasn't 1 second (!)....she was ticked (!) when my son beat her with his Suburban mud truck ( he had a hole shot...she did a break out...their still arguing who won)
That is fun! I remember the Javelins and the AMX. I was running a SS396 Camero then. The Factory Super Stock and AFX cars by American Motors were very competitive.
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Old 04-19-2006, 11:36 AM
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i've got desktop dyno 2003 and engine analyzer. but the hp#'s are really high with that small cam and head flow. 578hp 517lbs TQ with exhaust. it seems to go off the head flow more than anything. when i called ati for a stall and gave the guy the motor info. he was a little shocked and said to me. "that thing is going to make over 500LBS of tq" i told him it better

i've got a friend that runs high 9's N/A with a 3400lbs gremlin with a 401 with stock ported heads on 8 inch slicks. he has 13to1 compression and shifts at 7200 with a 4500 stall and it's a foot brake car. so if he can do it with stock heads i know i can hit 10's with a smaller stall and cam with indy heads.

the wife wants to race her car. but i don't think i want it going any faster than low 12's.


red65mustang the 2hp goes on the flow not the cc. say 300 for my valve lift now=600hp max port job and 650 lift cam= 680hp

here's a link to a 484hp 498tq motor with a small cam, junk intake, ok port job on stock heads. cam- Lunati hydraulic flat-tappet grind with 230/235 degrees of duration at 0.050, a valve lift of 0.0523/0.0540, and 108 degrees of lobe separation.
http://carcraft.com/techarticles/116...brute_engines/

i'm going for a dyno tune on friday. i'll post what my car makes at the wheels. i know that 727, ford 9inch and that huge indy intake are going to hurt.

GoneNova/406 good post. most of the people i talk to like small cam's and don't really believe the big cam myth. but my friend with the gremlin did over cam his motor so he could hook. with the smaller cam the motor was built with he had to go up to a 10inch slick and still couldn't hook at all. just blowing the tires off the line.
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Old 04-19-2006, 01:01 PM
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neat article...kinda old school....mix and match (Ford-Chevy-AMC) to find the best

more general references:
(fairly big part of the reason the Gremlin can do a 9)
350 chevy 8/1CR= 8800 lbs of downward force on the piston
350 chevy 12/1CR=15,000 lbs of downward force on the piston
not linear but ok to ballpark it as 1500 lbs per compression point
(his 13/1 will have roughly 3,000 more pounds on the piston then your 11/1)
(and his crank mains don't like)

whoops on the cc's....deleted it

footnote to all: found the stock heads flow: 225/155 (???? cause there were no details) just to reference how much he has increased it

yea, please do post the desk top and "real world" results
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Old 04-19-2006, 05:28 PM
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since there are no amc aftermarket rods to stroke a 401. to stroke the 401's they use chevy 6 inch rods to get a 4 inch stroke. they just came out with I beam rods for amc 360's and stock replacement 401 rods. that's all the rods we have to pick from. we have 2 places to get cranks but there over 2,000 bucks. we don't have many parts to chose from but there making a lot more than they did a few years ago

i'm really worried about the indy intake killing the hp/tq. that thing is huge. believe it or not a duel plane RPM airgap makes better #'s than a torker on indy heads with a small cam. i'm also running a holley 750 vac secondary with a choke i keep saying i'm going to get a proform but for some reason i hate to spend 500 bucks on a carb 870 bucks for pistons is not problem.

maybe i'll slap a 750 quick time on it. god, i'm nervous about what #'s it's going to pull.
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Old 04-21-2006, 10:29 AM
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well, both head gaskets are blown. the motor started braking up at 5500. i think the guy used the wrong valve springs or i had too little timing. i only had 33 total. the guy gets out of the car and say you have to much motor for you converter. i tell him the stall is a new ati. it must of been the trans slipping. he said it's wasn't a good pull and he's sure it makes more power. but with the blown heads gasket. we didn't want to try it again. i'm off to pull the heads off

i guess the #'s aren't that bad for a motor with a blown head gaskets and a slipping trans.

good news, he didn't have to tune the carb. he said the #'s where perfect.

350 rwhp@ 5000r's threw 5800r's around 340 lbs QT all the way across until it started braking up..

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Old 04-21-2006, 10:48 AM
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"ouch"
and dang it!!!....I was going to ask you to do a compression test to verify the desktop 11/1 claim and get a indication (?) what the cam was doing

fair chance the blown gasket would have shown up in the results! 11/1=roughly 180-200psi (depends on the cam) so a leak shows big time
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  #30 (permalink)  
Old 04-21-2006, 10:51 AM
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Quote:
Originally Posted by 71javelin
well, both head gaskets are blown. the motor started braking up at 5500. i think the guy used the wrong valve springs or i had too little timing. i only had 33 total. the guy gets out of the car and say you have to much motor for you converter. i tell him the stall is a new ati. it must of been the trans slipping. he said it's wasn't a good pull and he's sure it makes more power. but with the blown heads gasket. we didn't want to try it again. i'm off to pull the heads off

i guess the #'s aren't that bad for a motor with a blown head gaskets and a slipping trans.

good news, he didn't have to tune the carb. he said the #'s where perfect.

350 rwhp@ 5000r's threw 5800r's around 340 lbs QT all the way across until it started braking up..
My experience with blown head gaskets has always been with too much timing in combonation with nitrous and compression and a lean condition. Did you by any chance have a AF ratio monitor? A lean condition with too much timing might cause excessive cylinder pressure. Something else that could duplicate this condition is bad gas. Try some race gas on the next run.
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