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Old 10-03-2006, 07:47 PM   #151
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Quote:
Originally Posted by Patrick Olsen View Post
Thanks, Matt, that's good info. Intuitively that has always made more sense to me, so it's good to see some real numbers that would seem to back up what my brain thinks.

Pat
Let's try not to distort that information into making people believe that at the low n/a power levels we typically talk about here, the number is still constant. At the level we're dealing with on a daily basis here on the forums, a percentage still works best to estimate losses to the wheels.
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Old 10-03-2006, 08:48 PM   #152
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You could figure two aspects accociated with driveline loss. First, you have rotating mass of all the rotating parts. Inertia takes up X amount of power. The total energy used to speed all these parts up from 2000 or 3000k rpm to redline is always the same. In terms of work, we apply it per time. The power associated with spinning up the parts is drug out over a longer time with a low powered car. A high powered car can spin these parts up faster, but it takes a greater effort to do so, same net energy, more work. This is pretty exact. Rotating mass and rotational speed difference does not change. If you dyno from 3k to 7k, it's the same energy always. Yet, if you did it in half the time, you just doubled the work, i.e. HP sucked up.

I wonder if you could use a load bearing dyno to calculate this, plot out a large number of static torque values through the rpm range, calculate HP, then run it dynamically and measure time. I'm curious if you couldn't extrapilate the inertial mass from that...hmm.

Second, we have friction. Friction is based off the applied force. The more force applied, the higher the friction. Now, the linearity of this depends on the characteristics of the surface. You have gears, bearings, bushings, the tires on the dyno, everything in contact with everything else. All these things have their own relations to each other and their own friction curve. In a general approach, we could assume this to be linear. Double the force, double the friction. However, in real life, that's not the case. Double the force may have a friction force greater than 2x or less than 2x. Heck, motor oil and gear lube may be something like 1.05x. I have no clue.

Then consider which one is more influencial. Is inertial spin up sucking up 80% of your power, or is all the friction between all the mechanical parts draining away the majority of your HP?
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Old 10-03-2006, 09:03 PM   #153
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You do realize you just wasted your time looking all that up in "Engineering for Dummies", and that all dyno's use software to take all this into consideration, just calculated in different ways depending on how that dyno measures power and torque, right?
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Old 10-03-2006, 10:52 PM   #154
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MeanEditor (whom I am guessing is Ryan under a new screenname?),

I think my car and dyno results helps to support the point you are trying to make. I ran the spicy cams for nearly 2 years before I did the headwork, and have before and after dyno runs. What I found with my car is that the headwork just bumped the powercurve. It didn't shift it at all, and my peak HP is made at pretty much the exact same RPM's that is was at before the headwork. This suggests to me that it's the cam that's setting that point.
Matt,

Would this then mean that if you were A) happy with your current RPM power range / cam profiles or B) had to choose between doing cams or head work that head work would be the better choice?

Obviously doing both would be optimal, but for a DD street car looking for more power in a real world useable power range of say 2,800-5,800RPMs instead of max HP gain at 7,000RPMs it sounds like head work may be a better route. Or would this be a situation where the stock cam profiles are so "safe" that there would be no benefit to the head work without the spicy cams?
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Old 10-03-2006, 11:30 PM   #155
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You do realize you just wasted your time looking all that up in "Engineering for Dummies", and that all dyno's use software to take all this into consideration, just calculated in different ways depending on how that dyno measures power and torque, right?
This is an educational and informative thread. I don't think he wasted any time at all.
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Old 10-04-2006, 12:23 AM   #156
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I know people will love this, but I just discovered I missed some questions/comments directed my way.

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Originally Posted by hatchbuilder View Post
OK Pat challenge taken.
Your 168hp. What did you dyno stock? Can you answer that simple question? Because you will note that what I said WAS significant. We need to see gains over baseline pulls. All your numbers indicate are a high-reading dyno. Are you implying that you have a stock 168whp?
My baseline runs were 103whp, 105whp, and 106whp. Oh, did I mention those were on a different dyno? Read the multiple dyno result threads I've posted in this forum and you'll find all the information. I'm certainly not trying to claim 168whp stock.

Quote:
Originally Posted by hatchbuilder
Are these numbers corrected by the dyno to read what the theoretical brake hosepower figures are (which is what I am going to assume) or are they wheel?
Why would you assume a chassis dyno would spit out BHP figures? That's not even possible (for the reasons you yourself have laid out.)

Quote:
Originally Posted by hatchbuilder
You do not set up a dyno the same way for an STi than for an RS etc.
You've really got my curiosity piqued on this one. Having been to a few dyno days with mixed types of cars, I'm honestly curious what you mean by this, as I haven't seen any difference in the way the dynos were set up.

Quote:
Originally Posted by hatchbuilder
Your statment about making 14whp peak with exhaust and header and 18whp at redline does not make sense.
Peak power doesn't occur at redline - my stock runs showed about 12whp less at redline than at the peak. So it is entirely possible for the engine to show a larger gain at redline than at the peak.

Quote:
Originally Posted by hatchbuilder
Are you saying the entire graph shifted up and to the right? You made more power everywhere?
Yes and no. Look at the graph - http://www.submariner.org/thepno95/P...comparison.jpg .

Quote:
Originally Posted by hatchbuilder
Also, I bet the addition of tuning is what made the 10hp, not the intake but that is neither here nor there.
I had an S-AFC already tuned (since the car ran grossly rich even with the stock intake). I added an Injen CAI and retuned the S-AFC (only a little bit, really). I went from 132whp to 142whp on a Dyno Dynamics dyno.

Quote:
Originally Posted by hatchbuilder
So you made 24 peak whp with intake, header exhuast and Tuning. That sounds about right. Where is your argument? You made a bit more than I postulated speaking in GENERAL terms.
The intake and tuning were the last two things I ever did (well, until I replaced my MRT header with an OBX and dyno'd again to see what difference it made), so I don't have any numbers for intake/header/exhaust/tuning. After I did the MRT exhaust I bit the bullet and blew a bunch of dough on heads and cams, then did the intake and S-AFC later.

Quote:
Originally Posted by hatchbuilder
You claim 168whp (which I will assume is your end number) which means your stock baseline is 144hp.
Actually, my baseline was ~103whp, but that was on a different type of dyno (Dyno Dynamics Low Boy). I made 142.5whp on that same dyno. I've since (with essentially no changes) made 168whp on a Dynojet.

Quote:
Originally Posted by hatchbuilder
So lets say that your dyno is actually trying to calculate bhp. that would mean that 144/168=~87 which is a 13% drivetrain loss which puts us at about 125whp which is just about right, and it falls comfortably into a 5% margin of error for a not so precise machine since you can't really know until you take the motor out and put it on an engine dyno. Which none of us has.

Math owns you.
So (final whp)/(baseline whp) = drivetrain losses? That's, ummm, pretty creative. It would appear that math (and basic dyno calculations) own you, my friend. If any of us manage only 13% drivetrain losses through an AWD drivetrain it'll be a miracle! Hell, that would be pretty good for a 2WD car!

Assuming that I'm still making roughly 40hp over stock (since there were no significant changes to the engine between the Dyno Dynamics runs and the Dynojet runs), then my somewhat imaginary baseline number on the Dynojet would have been ~128whp (40whp less than what it puts out now). So (165bhp - 128whp)/165bhp = 22.4% drivetrain losses. On the Dyno Dynamics (on which I did do a fun stock runs) it was (165bhp-103whp)/165bhp = 37.5% drivetrain losses.

Quote:
Originally Posted by hatchbuilder
As for my own experiences with this motor. They are my own and I don't feel the need to tell you all about it until you can really tell me how I am SO completely wrong.
I have an RS, I built it to a certain level of modification beyond bolt-ons. I can look at my begining basline and my end point and see the difference that is the key.
Thanks for sharing your experience with the rest of the community.

Pat
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Old 10-04-2006, 12:27 AM   #157
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I don't know what corrections dynos have. I'm sure the operators are aware of corrections, probably pretty standardized by now...at least I would hope.

Still...
when someone buys a car that's rated at 150HP and puts down 100HP on the dyno, there is no correction. They see 100HP and say wtf. People were discussing linear/non-linear ideas. My mind goes weeeeeeee, and I share my thoughts.

Sure there's probably standardized corrections, and the operator knows this or at least can have the machine spew it out for him. However, what does the average person know about loss? How many people wonder where their power went? Sure someone can say, "it's driveline loss," and it's X amount or Y%. Ok. That's super, but why? I decided to share my understanding of why.

No need to look up anything. It's all in my head. Oh god the voices! Make them stop!!!
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Old 10-04-2006, 12:47 AM   #158
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Originally Posted by Back Road Runner View Post
I don't know what corrections dynos have. I'm sure the operators are aware of corrections, probably pretty standardized by now...at least I would hope.

Still...
when someone buys a car that's rated at 150HP and puts down 100HP on the dyno, there is no correction. They see 100HP and say wtf. People were discussing linear/non-linear ideas. My mind goes weeeeeeee, and I share my thoughts.

Sure there's probably standardized corrections, and the operator knows this or at least can have the machine spew it out for him. However, what does the average person know about loss? How many people wonder where their power went? Sure someone can say, "it's driveline loss," and it's X amount or Y%. Ok. That's super, but why? I decided to share my understanding of why.

No need to look up anything. It's all in my head. Oh god the voices! Make them stop!!!

Damn dude
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Old 10-04-2006, 12:48 AM   #159
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On a recent dyno day, I put down 121HP on a Dyno Dynamics, stock '02 Forester with just an I-Speed reflash. I was suprised seeing so many RS cars with near 100HP numbers but disappointed too as basically everything else at the dyno day was a WRX putting 200HP and well above.
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Old 10-04-2006, 01:13 AM   #160
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Wow, that's damn impressive, Back Road Runner!

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Originally Posted by FalconRS View Post
You do realize you just wasted your time looking all that up in "Engineering for Dummies", and that all dyno's use software to take all this into consideration, just calculated in different ways depending on how that dyno measures power and torque, right?
If all dynos take this stuff into consideration then why don't they all spit out the same numbers?

The fact is that drivetrain losses can't be taken into account. There is no way to measure them unless one has a chassis dyno and an engine dyno at hand and can measure the output both ways. The numbers that a chassis dyno spits out are wheel horsepower numbers, that's it. Their relationship to crank horsepower numbers can be guessed at, but there's no way to "use software to take all this into consideration."

Pat
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Old 10-04-2006, 01:45 AM   #161
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I will say it was a cool day, mid 60's maybe? humid...(sprinkled lightly). The conditions were definately favorable. In a relative sense, someone did come down with a stock wagon, 2.5L turbo. It put down 181HP. On the third run of each turbo car, they'd squirt down the intercooler, blow a fan on it for a moment, then run the final run. With this one, they wet down the intercooler and threw a blower fan(kind you see on the floor at supermarkets during the rainy days) right on the intercooler like normal for the last run and then kept it there during the pull for fun, got a dead even 200.00HP. It was the last car, last run, just did it for fun. It's interesting to show how much an intercooler can affect power with just a little air blowing through it.

A lot of the 2.0L WRXs were doing a hair over 200HP. There was a 2.5L WRX with the exact same setup as a 2.0L version, same upgrades. The 2.5L put down 70 more HP with just the .5L difference.

The winner of the day was a nicely modded XT, did 275HP/290Tq, a beast.

Someone brought along a friend with a supercharged Mustang, put down low 440HP. It put down 460 something with a couple less mods on a Dynojet dyno previously. The operator figured he's currently making about 490HP at the crank, about 50Hp lost via driveline.

Oops, I probably shouldn't be mentioning turbo cars in a NA thread, lol.
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Old 10-04-2006, 03:28 AM   #162
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If all dynos take this stuff into consideration then why don't they all spit out the same numbers?
Lots of ignorance in this thread. Dyno's are developed by TEAMS of engineers that know what they're doing. Having one guy roll in here thinking he's just solved all the problems with a 3rd year engineering school essay (I know because I was one) is simply ludicrous. Unfortunately, like every industry, they have to work around patents for the systems they're trying to build, making sure they don't infringe on someone else's design. Some dyno's use a free-spinning heavy drum. Some use a magnetically loaded drum, some use fluid, some use a braking system to create load against which torque/power is measured. None of these are perfect, they all have deficiencies and all rely on different educated estimates. How dyno's work and why one dyno will give completely different numbers than another (even if both are the same type) has been debated since the car to be strapped to one was measured. A dyno operator can very easy change some calibration points in his own computer and have the dyno spit out lower or higher numbers.

The only truly accurate way to measure what your engine can do, is by measuring it against itself, on the same dyno, and hope nobody's messed with the settings, and hope the calibration is still the same as it was the last time you put your car on the thing. That's why horsepower wars always make me laugh. Car A makes 300, Car B makes 310 and gets the bragging rights. Too bad they're across the country from each other on completely different dyno's. Who the hell knows who's telling the truth or whose system is even remotely accurate?
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Old 10-04-2006, 03:56 AM   #163
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I'm not really sure what you are saying with your long rambles. Also, testing standards go a long way to mitgate the problems you are referring too. Engine dynos with properly metered/humidified/conditioned airflow and consistent operating temperatures give consistent results.

Last edited by LastResort; 10-04-2006 at 04:11 AM.
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Old 10-04-2006, 04:12 AM   #164
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I'm not really sure what you are saying with your long rambles. Also, testing standards go a long way to mitgate the problems you are referring too. Engine dynos with properly metered/humidified/conditioned airflow and consistent operating temperatures give consistant results.
Just like two RS' of any given year will always crank out exactly the same number on your perfect, naive little world's dyno, right?

I'm talking chassis dyno's here, not engine dyno's. Engine dyno's tend to posess a lot more accuracy, partly because they're almost always within a heavily controlled environment to start with. There's a reason the SAE goes on crank horsepower and not wheel.
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Old 10-04-2006, 08:28 AM   #165
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Just like two RS' of any given year will always crank out exactly the same number on your perfect, naive little world's dyno, right?

I'm talking chassis dyno's here, not engine dyno's. Engine dyno's tend to posess a lot more accuracy, partly because they're almost always within a heavily controlled environment to start with. There's a reason the SAE goes on crank horsepower and not wheel.
Why don't you take your little thread hijack elsewhere?
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Old 10-04-2006, 11:16 AM   #166
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end dyno debate

check this thread

http://forums.nasioc.com/forums/show....php?t=1105529

thank you
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Old 10-04-2006, 11:30 AM   #167
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Why don't you take your little thread hijack elsewhere?
Who's threadjacking? Click back a couple of pages, I joined this thread to discuss N/A horsepower, and made some pretty good posts about it, if I do say so myself. The dyno discussion actually came about rather organically through the discussion of n/a horsepower production, through a combination of several people. Why you feel the need to target me specifically....not sure...something against Canadians?
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Old 10-04-2006, 01:29 PM   #168
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Please stop diluting the white paper thread with off-topic material!

This was meant to be a reference thread, not a brawling match over dynos. How about a little respect for something that was long overdue, and done correctly?
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Old 10-04-2006, 02:08 PM   #169
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Matt,

Would this then mean that if you were A) happy with your current RPM power range / cam profiles or B) had to choose between doing cams or head work that head work would be the better choice?

Obviously doing both would be optimal, but for a DD street car looking for more power in a real world useable power range of say 2,800-5,800RPMs instead of max HP gain at 7,000RPMs it sounds like head work may be a better route. Or would this be a situation where the stock cam profiles are so "safe" that there would be no benefit to the head work without the spicy cams?
The Cobb spicy cams make peak HP at 5800rpms (at least on my car with a stock ECU). The stock cams will make that peak power 500-600rpms lower. In my mind, there's no reason NOT to run the spicy cams without a raised redline.

As for your other question it's hard to say which is better; headwork or cams. My gut is that the cams are better. Cobb has dyno tested them to around 15whp on an otherwise stock car. I have never seen anyone dyno test ported heads on a stock car. All I do know is that the headwork gave me an ADDITIONAL 12whp over what I already had with everything else. What they would do alone is up to debate. But you can't argue with the costs. Ported heads tend to run more than $1000. Cams run between $200-500. And that's not even taking into account if you have to pay someone installation costs. I know guys here have ported their own heads, but it's not something I encourage. I think it needs to be done by a professional, with access to a flow bench and experience in what works and what doesn't work. My port work is deliberately fairly conservative as I do not have a race cam and didn't want to loose my port velocity or alter the nature of the heads...
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Old 10-04-2006, 05:55 PM   #170
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Thanks Matt, that makes sense. I was under the impression the spicy, or any perf aftermarket cams, gave most of thier additional power higher in the rev range (as that's the case with the cam packages available for my other car) with none or minimal change in low end TQ. I'm looking for "up to the left" or just "up" not up to the right in the power band.

And I was basing my which is better question on the subiesport prices. At $675 for the head work at Pineapple + $150 for install, and $150 for removal, for a total of approx $1,000. VS spicy cams for $499 plus 8 hour install cost of $650 for an approx total of $1,150. Unless the cams need to come out for the head work. Also assuming if you weren't looking to rev to 8K you wouldn't need the new valve springs/retainers etc. in the ZTH engine.

And 1 other quick question, why is there no/minimal discussion regarding porting/polishing of the intake? not possible, no potential benefit or rediculously cost prohibitive?
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Old 10-04-2006, 06:26 PM   #171
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Originally Posted by SubaDuba420 View Post
Thanks Matt, that makes sense. I was under the impression the spicy, or any perf aftermarket cams, gave most of thier additional power higher in the rev range (as that's the case with the cam packages available for my other car) with none or minimal change in low end TQ. I'm looking for "up to the left" or just "up" not up to the right in the power band.
I would imagine you'd have to have your own custom grind done to accomplish that. OEM cams are generally designed to hit the mid-range since that's where John Q. Public and Sally Soccermom normally drive. Cams that shift the power band up and to the left (or even just up) generally aren't done by the aftermarket.

My results were with heads and cams, so I can't say how just cams might have changed the power band. My educated guess is that even with just the Cobb Street/Stage 1 cams (which is what I have) on stock heads the power band would be shifted to the right.

If you're looking for good low/mid-range, I highly encourage you to look into the Cobb/Rallitek/OBX equal length headers. I have the OBX ones, and just as Cobb's dyno graphs show, I saw significant gains throughout the RPM band - "significant" meaning 10+ ftlb everwhere. Search for my name and OBX and you'll find the dyno graphs and full explanation.

Quote:
Originally Posted by SubaDuba420
And 1 other quick question, why is there no/minimal discussion regarding porting/polishing of the intake? not possible, no potential benefit or rediculously cost prohibitive?
I think it's a bit of the last two. Cobb stated a couple/few years ago that the intake runners could flow a little more than even a head with aftermarket cams would require. I don't remember if that was a stock head with bigger cams, or a ported head with bigger cams. If it was the former, then for those of us with ported heads and bigger cams there may be some benefit to having the intake manifold ported and polished.

Storm has had some positive results with an intake manifold he (or someone who works on his car with him) fabricated. Perhaps he'll chime in with some more details.

If one chose to port/polish a stock manifold, doing so wouldn't be cheap because of the somewhat unusual configuration of the intake manifold on a flat engine. You could either have the manifold Extrude Honed (which, according to their price sheet would run you $450, plus shipping there and back), or you could have a shop cut the thing open in order to access the plenum and the runners and then weld it all back together. I don't know how much that would cost, but I'm sure it wouldn't be cheap. For the $450 that EH-ing would run you I'd be inclined to build a manifold like Storm did.

Pat
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Old 10-04-2006, 06:43 PM   #172
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And I was basing my which is better question on the subiesport prices. At $675 for the head work at Pineapple + $150 for install, and $150 for removal, for a total of approx $1,000.?

--

The cheapest place I can find for head porting and polishing is DPR, and it costs $1300
Plus the local labor for install is 12 hours which runs $1200
I would like to know how you got away with just $300 to pull and replace heads, and how do I contact Pineapple?

--
VS spicy cams for $499 plus 8 hour install cost of $650 for an approx total of $1,150.


-

Delta cams cost $75 each

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Old 10-04-2006, 06:55 PM   #173
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Quote:
Originally Posted by Patrick Olsen View Post


I think it's a bit of the last two. Cobb stated a couple/few years ago that the intake runners could flow a little more than even a head with aftermarket cams would require. I don't remember if that was a stock head with bigger cams, or a ported head with bigger cams. If it was the former, then for those of us with ported heads and bigger cams there may be some benefit to having the intake manifold ported and polished.

If one chose to port/polish a stock manifold, doing so wouldn't be cheap because of the somewhat unusual configuration of the intake manifold on a flat engine. You could either have the manifold Extrude Honed (which, according to their price sheet would run you $450, plus shipping there and back), or you could have a shop cut the thing open in order to access the plenum and the runners and then weld it all back together. I don't know how much that would cost, but I'm sure it wouldn't be cheap. For the $450 that EH-ing would run you I'd be inclined to build a manifold like Storm did.

Pat
One correction to add here. The stock manifold flows 236cfm vs 240cfm for the heads, according to Cobb's numbers. The primary reason the manifold hasn't been addressed more is the second part mentioned here. It's generally cost prohibitive...
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Old 10-04-2006, 07:02 PM   #174
SubaDuba420
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Pat,

I guess I really meant "up" across the whole RPM range as opposed to gains only above 5k. And also why I thought the head work without cams might work well for a street car where you don't want to cruise around at 5,200 rpm to be in the power.

I figured as much with the intake design. Good info on the intake VS head flow, explains why you don't hear much I guess.
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Old 10-04-2006, 07:16 PM   #175
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Quote:
Originally Posted by G.Subramaniam View Post
--
The cheapest place I can find for head porting and polishing is DPR, and it costs $1300
Plus the local labor for install is 12 hours which runs $1200
I would like to know how you got away with just $300 to pull and replace heads, and how do I contact Pineapple?
--
As I mentioned, I was using estimates based on the SubieSport ZTH engine build article. They stated $675 for the head work they had done and $150 for head installation, I added another $150 for removal. If these prices were based on the work being done while the engine was out of the car I guess it would be more, the numbers are useless and I made an internet ASSUMPTION.

Estimates, that's all, I haven't gone and priced the work out just getting some info. And after reading your post I checked the cobb site and you're 100% correct, head install is 12-15 hours so the ZTH cost must have been with the engine removed.

So it looks like the answer is: cams FTW over head work on both price and power.
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