20+ Horsepower from exhaust
 

This smells like bull$hit to me



http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7948785235&catego ry=33630

I dont know about that product but i know you can get BHP gain from exhausts of around 20+

There is now way your going to get 20hp out of an exhaust on a Boxster, maybe on other cars but not a Boxster. If there is an exhaust out there that will give me 20hp I will buy it tomorrow and sell my GHL system today
Automon

Yes you can, i have seen them.

WWW.FVD.DE offer a boxster one with 20bhp gain and many other stores.
This aint a scam. Its well known about the 20+ bhp for a mod boxster exhaust

http://img150.exs.cx/img150/1118/1008pw.jpg

Anyone interested in a used (5000 miles) GHL system sounds great but it will not give you 20hp. This is the system with the twin 5" cans
Automon

Hmmmmmmmm, maybe the 2 is right.
 

But not the zero. Show us some legit dyno scans from a reputable and neutral shop. You will sell many if this is the case. We have all heard and read from many tuners the world over that the oem system is hard to beat. Ruf says 2-3 h.p. with their system. Something seems fishy here. It's hard enough to get 20hp from intake exhaust and ecu (especially without headers and cats).
Show us the proof, we will be happy to review it! :)

i agree with fletch; there is zero chance of a 15% horsepower gain in a car as finely tuned as a porsche by simply bolting on a muffler. in most cases, without other changes in the intake / fuel maps, you will LOSE horsepower by bolting on a muffler.

for a comparison, FVD's tuning program for a 2.7L includes the following:

tuned headers
DME map
sport air filter

this yields 172kW, or about 230HP. this is an increas of a whopping thirteen horsepower from replacing the headers and reprogramming the whole computer. DME aside, even with upgrading cats, headers, muffler and intake, you'd be lucky to see 17HP in that car.

To get 20+ HP from this car you will need an exhaust, cats, headers, intake and an ECU reprogram. Then you will get close to 30HP more. Just a muffler? Never!

unless you fell for the banana in the tailpipe.....

Sorry but i think you can.
A basic induction kit goves 7-12bhp

A dyno can settle the score. Could you cut a deal with the supplier that they will refund your dough if you can get close to the 20 they advertise?

I'll eat the muffler if it produces 20hp alone. There's no friggen way! I think someone on another board has already dyno'd a bunch of aftermarket mufflers. They all produced from around +3hp to -3hp. Also keep in mind that usually any gains are up on top at the expense of losing torque down low.

I'll help Lux out and eat half the muffler that makes +20hp. No way no how with just an exhaust alone. :dance:

But there is hope...
 

I spoke with a tuner in Sacramento today. They have a dyno and tune european cars and the like. They sell the unichip. He said he can make hp in my car. Custom mapping after my mods are installed. I also found this interesting dyno chart on Unichips website. They have a great rep. Maybe my goal of 250 is doable (I am starting with 225). :cool:

Btw
 

I am awaiting verification of which model yesr this is. On their website unichip.us you can see all the numbers. This was with an scargo intake. Not too shabby. This is of course bhp. :D

Facts: To get 20HP out of the boxster (2.7L), you need to do one of the following:

1. Decrease manifold air temp by 4% absolute (about 50F)

2. Increase manifold air pressure by 9% absolute (about 1.1 psi)

3. Increase overall thermal efficiency of engine by 10% abs (3% of fuel heat val)

4. Increase lambda number by .08 (to 12:1 stoicheometric rato [13.1 is stock])

which one of these does a muffler do? or an intake? discuss.

If you add :rolleyes: a chip, intake and exhaust mods, I can see getting to 250. I assume this would all be emissions legal? That is a big deal in many states.

I have a couple of questions with this subject:


One is gas mileage. Would a muffler like the kind mentioned improve or hurt your gas mileage? What if you would include a power flow kit, would that enhance the performance and compliment those mufflers? With a limited budget which end should I concentrate on (intake or exhaust)?

And now the stupid question, how do you read a dyno chart? Do I compare the blue lines with red lines or the dotted line with the solid line? Sorry, but since I came aboard not too long along I have dffinitely learn a lot from this forum. Thanks guys.


spgribben007

You will have a hard time getting to 250 with an intake, exhaust and chip even if your exhaust includes headers. without the headers (muffler only), my guess would be 242 or so. in fact, i would get the headers before i got a muffler (it's a larger constraint in the case of these cars).

BTW, per my last post, here is what THESE mods would do:

Muffler / Intake:

increase thermal efficiency of motor by reducing volumetric air losses due to friction

Headers:

same as above PLUS:
increase thermal efficency of motor by balancing relative output of each cylinder

ECU:

1. increase rev limit (remember, hp=torque*rpm/5252 so same torque at higher rev=higher HP

2. increase lamda value to provide 12.6:1 stoichiometric ratio

3. adjust spark map to account for #2

4. adjust fuel / spark map to account for #1


So how do these pan out on paper?

ECU:
Just increasing lambda for a 12.6 ratio would yeild 225 HP at 6000 rpm (using the dyno graph in this thread for locations of peak values).

This equals 197 lb-ft of torque.

If we move our HP max from 6000 to 6800 rpm and estimate a torque loss of 20 for 177 lb-ft at 6800, we now have:

229HP


Intake / Exhaust:

Intake: static pressure losses can account for at most about .25 psi manifold pressure. in our case, if we say we get the entire .25 psi, we now have:

236HP

Exhaust: In order to get the .25 psi manifold pressure that we gained above (from the intake), the exhaust would have had to be tuned to the itake in order to apply the full .25 psi.

We do, however, gain efficiency from the headers.
it's a lot of math, but here goes:

with the changes we've made, we are now burning .94 kg per minute of fuel at our 6800 rpm HP peak.

this translates into about .12 gallons per minute.

our friend gasoiline contains about 46MJ (yes, MEGAjoules) per kilo of fuel.

since we are burning almost a kilo a minute, that means we're cranking out 717 kilowatts of power.

this translates to, believe it or not, 962 HP available from the fuel we're burning. We're only making 236 HP, so we are 24.5% efficient *at this RPM*. The rest is lost to heat, friction, etc.

A tuned header can decrease compression effects at the manifold. this means that the exhaust exiting the engine can more easily expand (it's HOT!) due to reduced interference with other cylinders.

the more easily that this can expand, the cooler it is upon exit of the motor AND the lower its pressure. this does a few things:

this removes some of the load necessary for the pistons to PUSH the exhaust out of the motor in addition to the exhaust gas transfering less heat to the motor.

per newton, it also reduces pressure of gas against the pistons due to heat expansion.

finally, it transfers less heat to the engine.

all of these in our case will add up to about a .5% increase to our thermal efficiency AT THIS RPM (again, we start to get inefficient at the upper limits of our rev range). .5% of our 962 gross HP yeilds about 5HP.

We are now at:

241HP

So, the SHORT answer to your question "can i get 250HP from exhaust / intake / ecu" is: Not on pump gas. :-) you're looking at 241/242 tops (unless you live someplace that's freezing cold and at sea level).

spgribben007:

exhaust / intake will improve your fuel efficiency under normal driving conditions. with a limited budget, i wouldn't do anything at all to these cars since gains are marginal at best.

the most bang for the buck short of a supercharger would be your ECU program, but you only get the most of it if you also do your air intake (muffler really not necessary on this car) and headers, all of which equals the price of the supercharger (almost).

as for the dyno charts, you are graphing torque and HP vs. rpm at the same time. torque is your flatter curve (for our purposes). hp always = 0 at 0RPM, so the HP curve starts very low. the torque curve is showing you, at each rpm, what your torque value is. the HP curve is showing you your HP output at each rpm. horsepower is derived from torqe (HP=torque*RPM/5252).

in the above chart, the dashed lines are torque and the solids are HP.

the colors usually illustrating before / after some type of mod.

Insite

Thanks for the suggestion and quick response.

I would never question your math...Insite
 

But I would disagree about the ultimate gains acheivable. The current model has 240hp and I believe 197 tq. They did not change the internals of the engine, including cams. They did enlarge the throttle body, add factory manifold (header style) and ecu changes, as well as intake manifold changes (how much I do not know since my 04 has the flapper style intake as well). I believe it is made of plastic now which may help the intake temp a bit.
All relatively subtle changes for 240 h.p.. Is this the last evolution of this motor power wise (no way). But remember Porsche does not want to spend a fortune on exclusive parts and tuning for just this mill and they have noise regulations and blah, blah you know to deal with. Can you make it smog legal sure. The headers will delete the pre-cat but if you use dual o2 cats that are at least 200 cell and get the ecu tuned properly a/f ratio. You should be fine. The pre-cats are for some tailpipe bag test only (not sure what that's about). Ultimately the sniff test on the dyno tells the tale.
I also think unichip is pretty reliable so there dyno numbers along with the cold air intake from scargo should be very close. Of course we all know about the power range of these motors from the factory right (they differ) some are stronger than others. Perhaps the best combo is Intake, Headers, ECU.

P.S. I think this is a great topic and Boxster tuning is just getting it's feet wet. I hope we can someday get a reliable supercharger kit or a less expensive turbo kit 24k is ridiculous. Don't get me wrong the Boxster is a great car but I noticed recently how the power really flattens out past 6k and we have 7200 to work with :D

Exhaust mods
 

I doubt very much the claim of 20 hp plus. Neil from Orton Motors who specializes in doing performance mods for 986's mentioned that changing the headers from the more restrictive factory model will result in a freer reving engine. He did not mention anything regarding hp additional for doing the mod.
He does do the engine swaps which new engine costs are prohibitive. 16K for the 3.4L and 18K for the 3.8L

Fletcher -

good points. i think that in addition to the changes that you mentioned, the majority of the gains in the 987 have to do with RPM and nothing more. i think some revisions to the intake have allowed them to maintain good driveability in the low rev ranges while further expanding the top end's spark map / fuel map / variocam program to move the torqe peak further up the ladder.

if you look at the dyno curve on the previous page, all it would take is moving / extending the flat part of the torqe curve (190 lb-ft in that graph, blue curve) from 6000 RPM (peak HP of 217) to 6630 RPM and you now have 240HP. if you go to porsche's website, you will see that indeed, peak power now occurs at 6400 RPM. this isn't the full 6630 that we needed, so they have added 7 lb-ft of torque; easily realized with the larger throttle body and new headers.

i have LONG believed that they drastically underrate the rev limit capabilities of their cars. think about this: my 1986 toyota celica was a 2L 4-cylinder. it redlined at 6900 RPM. It did this with cylinders and valves that were LARGER than the boxster's (2.0L / 4-cyl = .5L / cyl vs. 2.7L / 6-cyl = .45L / cyl) and connecting rods that were longer. from a force perspective, the new box generates 33.33 ft-lb of torque per cylinder; the celica generated 31.25.

considering the fact that a) the inertial mass of the reciprocating parts weighed more and b) this was a massed produced TOYOTA and c) that was 1986; one gets to wondering why that would be.

True
 

I have heard that Porsche is trying to milk these engines in small incriments due to the logical ceiling with the 997's 3.8L mill. They will spread out the h.p. and displacement to allow small steps just as with the original 986 the cap being 225 on my 04 2.7 (series 1 let's call it). Now with the 2nd gen motors they have upped the hp a bit. Like you said moving the obvious graph up a few hundred rpm and thus power and a bity of torque. My motors redline is 7200 and yet max power is at 6450 I think (but it really goes flat above 6k).
Ultimately if I could move that graph up to say max power at 7000 while adding headers, intake etc should get me close to 250. It would be more enjoyable to drive (pulling to redline) as apposed to falling flat at 6k. If all goes well it will be fun trying anyway.
I love tuning chat :D
P.S. I found out that contrary to what I thought before, Remounting the first o2 sensor to the cat (in the case of a high flow system, the one that WAS at the pre-cat) is not good. You have to extend the harness leads to the o2, that's bad. And by leaving it very close to it's original position but now on the headers (just past the collector) is the best shot and for no cel. Header wrap/jethot coating would probably help in this regard as well keeping the inside HOT for proper o2 reading. Neil @ Orton said he does this all the time with no cel's.

if you had a set of headers tuned for 7000 revs made, programmed ecu to match, added a larger throttle body / smooth intake, then you'll see 270HP IF the valves are large enough (not sure what the stock diameter is).

that assumes 150F manifold intake temp, .25 psi manifold pressure increase, no thermal efficiency increase, lambda=.8. Just the RPM increase alone, if the ecu has enough play to tune to this RPM, would give you 253. Add everything else and you get your 100HP / L.

Does anyone know the valve diameters or port areas for these cars? If we can find those, we can calculate the theoretical and most likely HP limits of these cars (without doing any serious engine work first).

Insite,
Good stuff, man. :cheers:

Fletch,
Custom mapping will yield the highest gains for sure. But even then it's still minimal gains. Dyno charts are great and all but you need to know the facts behind the numbers. Showing gains on 94 or 104 octane gas means nothing since we only have 91 in CA.

Why only 91 in CA? I live in $hit hole USA (MI) and I can get octane up to 110, which I run in my bike but not my Porsche
Automon

We can get 100 @ some Shell stations too!
 

You just have to look for it. You can blend to get 93 or 94. Try this blend chart if you need it.http://members.aol.com/SteveL1994/public/OctaneChart.xls

I just got my Dansk muffler and intend to install it over the next few days. My previous before/after showed 6+ bhp gain (at the wheels) from just the sports cat. I hope the muffler will yield about the same.

Look out for my report! I've not forgotten my intake kit. Just didn't have time to do it as the new year meant a lot of late nights for my line of work :(

but what about the S?
 

all this talk about the 2.7... what, if anything, would this or any other mods do for the 3.2? dont get me wrong, i LOVE the ponies I got, but I always want more. :)

More, more more.
 

Richard you can expect very similar gains if not more with a 3.2.

Clubhead which cat's did you install? Which headers? Was this on a 2.7, what year do tell all please! I read over on PPBB that the dansk makes some power as well but it is extremely hard to pin anyone down with dyno results against baseline etc. I think we are starting to see some exciting stuff coming for the Boxsters tuning wise and the more choices the better :D
Every hp counts, my goal is 250. We will see what happens.

Anyone know much about the ignition on these cars? Just about everything can be improved on :dance:

05 is going to be a fun Year!!!!! :dance:

I've Dansk headers on. You can find more details from my posting here http://986forum.com/forums/showthread.php?t=1805

It is not hard to pin down dyno results. All you need is time to go to/fro the dyno place after/before the installation.

Well, I can get 104 octane down the street at the local 76. But at almost $5/gallon I'll pass. I'm just suspicious of tuning for OBDII cars. Even Jim Conforti of BMW tuning fame said that OBDII is a ******************** and that getting 5-6hp is about it. Of course he's talking about a different car (E46 M3) but since all cars since '96 have OBDII I'd guess that we're in the same boat.

Remember in CA, the state govt has fiddled with EVERYTHING! Wouldnt be surprised if 92 and up was illegal!

Richard -

when i get home this evening i'll run a workup on the 3.2's mathematical likely / theoretical limits with these change.

thanks, insite....
 

i look forward to hearing what you have to say. :)