mytoy986

I have the pleasure of driving a 98 Boxster (that's boxster with the s!) not an S package. Now that I put the new clutch etc. in I would like to maybe get a bit more grunt out of the 2.5 So far what I've read and the people I've spoken to seem to suggest breathing! meaning an air intake and exhaust. Any feedback on these, like yeah or nagh What brands work best etc. NO I DO NOT WANT TO GO TO FORCED INDUCTION!! after all it has 86000 miles!

99firehawk

do it for sound not for power, your not going to get much power out of either

First986NJ

OK....I hear what Firehawk is saying, BUT....

I did this to mine recently. New headers, exhaust, and EVO V-FLow. First let me say I do not have access to a dyno, so this is strictly seat of the pants and observation. However I DO believe that there is a noticable difference in a couple of areas...at least with my car.

1) It sounds S-W-E-E-T. I would do it again for the sound alone...like Firehawk said

2) It appears to rev a bit quicker. When I am flat out on it shift points seem to be coming up noticably quicker. This is NOT foot position either....

3) I have broken the rear loose twice by suddenly nailing the throttle when pulling out from a cross street. I never had the car do that before. But the exhaust is quite a bit lighter now, so it could be a weight thing.

4) It pulls harder, longer.


My $.02 - If you have the change (it ain't cheep) do it, it's worth it.

986Jim

Simply pulling the snorkel is DYNO proven to give 5whp so thats a good start. An intake system will give you hp, Header are also proven for 11hp and 17lbs or torque. A muffler another 5hp and 1ft/lbs of torque. The sport cats or 300cell or less cats have never been dyno tested to my knowledge so no idea on that but they would likely be the same as a mufflers results.

Intake:
http://www.6speedonline.com/forums/s...ad.php?t=75281 Bisi did it on his dyno. 5whp and 3ft/lbs of torque. This is a Boxster S however the effect will be the same on a 2.5L. Though im sure some critics will come on and say otherwise A Evom intake will do better than that. Some have dynoed and said otherwise, however a dyno doesn't totally replicate the difference in additional cold air vs being on a dyno where air is stagnant even with fans still not the same.

Headers and Muffler:
http://turbowerx.com/page1/page18/page18.html Here 5-20hp across the whole range, and 5-15ft/lbs across the whole range on a 2.5L

http://986forum.com/forums/showpost....6&postcount=57
Base WHP: 169.27 With Headers: 179.27 With Headers & Muffler: 184.24
Base Torque: 147.91 With Headers: 165.85 With Headers & Muffler: 165.92
So, by swapping out the headers and the muffler, I gained almost 15 HP and 18 pounds of torque

So you can get power on the car by doing modifications, it's dyno proven as you have seen. With that said, gains are still small and high hp/dollar ratio so know what your getting into when spending money on the car. You will get some gains but don't expect turbo like power to show up with some simple bolt ons. You will likely get max with intake, header, exhaust about 20hp and the same in torque. Not sure on chips yet myself I have not gone there personally on my car. Maybe somebody can chime in about chips? There seems to be a lot of different opinion about chips on these cars. The people selling them claim 15hp gains but guys on dynos don't show any gains that I have seen. However that was always said about headers and mufflers and the snorkel in the past which we all know now that it does make power so who knows.

If your thrifty you can get the intake headers and exhaust for around $1200 bux or so and install it all yourself. That will be 20 or so HP and the same in torque, thats a good start and you will feel and hear that.

Regards,

First986NJ

Personally, I believe the claims of 20 - 25 RWHP with EVO intake/ Short tube equal length headers, and a performance exhaust. My headers look to be pretty much the same design as the TurboWorks headers.

Those are the mods that I just made to my 2.7L , and I would say that the 20-25 HP add feels about right for the equipment I put on. It is most definitely noticeable. My son says the same thing, he feels the HP difference is quite noticeable from the passenger seat.

$1200 might be a little optimistic though, at least for all new stuff. I just spent about $1800 for those parts...and believe me I shopped them. I bought the whole package from ImagineAuto.

Keep weight in mind too. I believe the general rule of thumb is that every 10 pounds is about 1 more effective HP. There is such a HUGE difference between the weight of my stock headers and muffler, and the headers and muffler that I put on, that I am sure I gained some effective HP through that weight reduction as well.

986Jim

And you should believe the claims. Just the header and muffler dyno proven for 15hp and 18ft/lbs of torque. So going from there shouldn't be too much of a stretch considering Bisi's dyno back to back 15 mins appart from the snorkel.

986Jim

99firehawk, not to start an arguement however your posts says

Then your sig says

I guess with all the dyno proof out there now, you can edit your post so you're not popping off?

J/K!!!

99firehawk

your not going to make a 2.5 boxtser into a hot rod, or any boxster for that matter, people think that by buying an intake that the mfg claims 25 hp for and the exhuast is good for 15 hp and then you take out the snorkal and get another 10 hp and then you get a reflash for another 15
and you added 65 hp to your car....................it doesnt work that way.
You will be doing well to get 20/20 more out of the car with a headers/muffler/intake and you will be in 3000$ +
IF you want more perfomance get a diffrent car step up to an s or to a 911.
90% of the people who feel a huge diffrence is purly physco sematic justifing next months credit card statement.
If you want the sound then by all means buy it for that.

arenared

You will get comparatively much less gains out of a 2.5L. The 3.2L S that you see used in most "reviews" is comparatively more restricted by the exhaust/etc. which is sized for a 2.5L. Also, the 2.5L does not have the two sets of cats and therefore already has a set of "headers". With an S, it seems like you can get 25 to 35 HP out of it while spending about $5K. On a 2.7L, I'd venture to guess around 15 to 25 HP with probably a lot of that from the headers. On a 2.5L, you're probably looking at an honest 5 to 15. Note that a lot of aftermarket parts are really "up to" 10 HP or whatever, and that gain is only at a certain RPM with losses possibly elsewhere. IMO, your best bet would have been to put in a LWFW when you had your clutch done. That would probably have given you the same seat-of-the-pants feel as all the other mods. You can do a few other mods for sound if you want, but if you want more power, I'd start saving for a used or reman 3.2L or a 3.4L which aren't all that badly priced anyhow.

blinkwatt

Hey Jim,

I actually tracked down a couple of people who bought the eBay(Top Speed) headers off of eBay and 2 out 3 three people had problems w/ the headers not fitting properly or leaking.

Did you ever get yours yet,I wouldn't mind hearing your opinoin.

gfl

Typically, the best you will do is move the torque curve up a bit. That will add (marginal) peak power, but probably at the LOSS of some low-end torque, which the 2.5L needs.

It will sound great.

And a great-sounding, bright red car, goes faster.

Grant

pecivil

yes Virginia you CAN turn the Box into more of a hot rod, but not with bolt ons.

blue2000s

+1 here. The flywheel will absolutely change the engine's personality.

Jay Laifman

Ok, the biggest claim above is +35hp, most claims tend to be in the 20hp range. I think all this continues to support 99firehawk's position. This is not very much more hp, and it's a lot of money to get there. So, the point is, why are you doing it? If you are racing and need every last bit of hp to be competitive down that back stretch, sure it makes sense - almost. Because if you are racing, these kinds of mods put you into a modified class, where the sky is the limit and this isn't even enough. If you are not racing, why do you need or want less than 10% more hp? Personally, I made the changes I made for my senses that define the driving experience (that is, my ears with my PSE and sport cats, and my hands with my B&M short shifter, though I don't know that I really care for my B&M). To me, it makes sense to spend money on something that improves my ride. Simply knowing that I have 10% more hp is meaningless.

Note, this is only my opinion. I know there are plenty out there who do in fact get plenty out of the simple knowledge that they have more hp. You have to decide where you are and what will bring you satisfaction for the money spent.

blinkwatt

The only mod that I have seen give off decent power gains for the price is the custom built exhaust on the Boxster Spec car. They gutted the inside of the OEM muffler and basically ran straight pipes in it and closed it all back up. Passes smog just cause it's looks stock and you can't tell anything was changed unless you open it back up! I have the dyno chart to show a +18lbs. of torque gain @ 4.5kRPM at the wheels, and about +10-11 HP @ 4.5kRPM as well at the wheels(this was tested on the 2.5L). The mod only cost $300-500 for shop to do it and that is the ONLY performance mod for POWER that I have ever seen worth the $$$ IMHO on the Boxster.