basic hp gains

Code_Kid · Post by **Code_Kid** » November 6th, 2005, 2:29 pm

well i know for simple performance CAI and exhaust.

im wondering what would be the best size pipe to run on k8 motor? im thinkin 2.5. but needs some ideas on a exhaust or muffler i will be running a straight pipe no Cat so are there any sensors or anything in the stock cats?

im really looking for a wicked sounding exhaust something different then others have the town runs APC mufflers really needs to flow good also.

also where can i get a good CAI?

just need a idea on a good sound and preformance exhaust and good flowing CAI.

cb2big4u · Post by **cb2big4u** » November 6th, 2005, 2:42 pm

MX3_Sleeper · Post by **MX3_Sleeper** » November 7th, 2005, 5:46 pm

Well it depends what sound/performance your going for...
If you want a loud sound well you should get 3'' piping the whole way with a straight pipe... If your going for a tuned sound that ACTUALLY gives you hp gains, then 2.5'' sounds good but you should still find out if that gives you proper backpressure/velocity. A rule is for every N/A engine, 1 inch for every litre of displacement. Can't go wrong with that, unless talking about a 6.7L thunderbird.

Vanished · Post by **Vanished** » November 7th, 2005, 6:14 pm

umm..yaaa rriiight..sorry bud but uh that doesnt' really work out..1.8inch exaust? No...mustang 5.0 liter? 5 inch exaust? uh..noo...2.5 liter KLZE with 2.5 inch exaust, yah but thats about it.

For K8 2.25 is the best choice. If your planning on getting a KLZE you might want to go 2.5. THe velocity would decrease alittle bit, but you would be set for a KLZE. 3 inches is over kill. It wouldn't make your exaust much louder, and it woudl make your car slower.

Most peopel don't like loud exausts, but if you do then get rid of your cat and you'll be good to go.

Nice exaust doesnt' always mean loud exaust. For muffler and resonators, get flowmaster.

Oh and APC = s---. Don't get it.

papa roached · Post by **papa roached** » November 7th, 2005, 7:58 pm

Vanished wrote:umm..yaaa rriiight..sorry bud but uh that doesnt' really work out..1.8inch exaust? No...mustang 5.0 liter? 5 inch exaust? uh..noo...2.5 liter KLZE with 2.5 inch exaust, yah but thats about it.

ok, round it up, 2 inch exhaust, the 5.0 mustang is probably running DUAL 2.5 inch exhaust pipes, thank you now, bye bye then

ikarus1 · Post by **ikarus1** » November 9th, 2005, 9:05 am

Unless you want to lose torque, I wouldn't change exhaust diameter on a stock car. And by stock, I mean stock heads, exhaust manifolds, stock intake manifold. Mandrel bends will flow up to 30% more over the same diameter crush-bent pipe. So if you want to replace something, get a 2.0 inch mandrel bent exhaust similar to the borla for the probe.

2.25 inch is good for a STOCK 2.5L which is what a KLZE is, and 2.5 if you have headers and no intake restriction, maybe. You'll still lose some torque and move the powerband higher, but the KL31 cams do that too. Just remember that the stock MX-3 GS exhaust was a performance-type exhaust * unlike a civic or other non-performance car * and doesn't flow that badly. Thats why when you bolt on headers to a stock exhaust you still gain HP.

sinhron · Post by **sinhron** » November 23rd, 2005, 10:27 pm

just buy a muffler and put it on your stock exhoust. On a K8 you won't gain much. maybe like 3 HP ?!

mx3stylez · Post by **mx3stylez** » November 23rd, 2005, 11:35 pm

a really nice sounding exaust set up is 2.5 inch pipe, high flow cat, not resonator, and a ractive fireball muffler. Thats what i put on my car when i still had the 1.8, and it sounded and felt great.

MX3 GSR for dummies · November 24th, 2005, 11:24 am

I am running a stock exhaust system now with a perfy muffler and it sounds sweet!!! plus the hp didn't drop so that's good too. Most RICERS end up blowing oil through there rings and making horrible noises which can resemble an exhaust and spend so much money just to gain a couple hp. I currently run a KLZE but with my K8 I put a 2.5 fully custom exhaust and it performed horrible. I can also say that a friend of mine slapped on a 2.25 and even that set-up was debatable. The stock exhaust is amazing for the mx-3 and anyone to apose this really doesn't understand how that exhaust works.----Keep the money saved in the KLZE DROP fund

markmclean · Post by **markmclean** » November 24th, 2005, 12:22 pm

Well, while its true that things like bigger throttle bodies and bigger exhaust help, by themselves they have minimal impact. Any engine builder/tuner would agree that if you increase intake volume, you must increase exhaust volume or you create a bottleneck. Thats the simple answer. The more involved answer would be to:
Increase Intake Volume
Increase Exhaust Volume
Maximize volumetric efficiency
The last one is the tough part. Minimizing the restrictions in A/F mixture is essential to making power. When looking for a CAI find one with as straight a line between airfilter and TB as possible. The more bends, the more restrictive the CAI. Second, having the valves cut and sized in addition to even some mild bowl work on the commbustion chambers will increase volumetric efficiency and have a big impact on the power of your engine. Camshaft selection is also important. Select a cam to meet your driving/idle needs to optimize the powerband. and lastly, choosing the right exhaust for your combination. too much back pressure is too restrictive, while insufficient backpressure wont scavenge properly and result in a loss in power.like the CAI, you want your exhaust to have as few bends and crimps as possible to avoid bottle necking. As an extra note, you should remember that adding larger TB, headers, injectors, etc will fascilitate a need to have your ECM modified to reflect the modifications. The stock settings will conflict with the changes resulting in error codes and loss in power. Now the really hard part...cost...These mods range from pretty cheap like the CAI, to spendy like head work, custom exhaust and ECM tuning. Decide what kinda power you wanna make and find the most bang for your buck.

These can be done over time so dont feel it has to be a pkg deal..once you finish all these mods and uncork your engine, you can fairly estimate an increase in WHP by 30-40 hp

markmclean · Post by **markmclean** » November 24th, 2005, 12:27 pm

one more thing...before dropping coin for things like horsepower in a bottle or a turbo setup, remember these things put considerable strain on your engine and it must be built to suit these add-ons, or you risk one expensive grenade. Even building up the topend as i described, you want to be sure the bottom end is in good shape or all that hard work and money will be for nought when you spin a bearing or throw a rod with your new and improved top end power. Let Common Sense prevail....good luck

MX3 GSR for dummies · November 24th, 2005, 12:48 pm

Well put Mark!! Finally someone who fully understands why making a lot of sound does not give power. The ecu programming is crucial. But as mentioned by Mark...expensive. To go through a couple grand for 30hp seems pointless when 70hp costs the same with the KLZE swap...then customive your exhaust. You have to choose to go for power or acoustics. Power being an engine swap and then set-up the rest properly....or acoustics and just have a good sounding exhaust wich is not expensive and still sounds good but doesn't jepordize your power.

markmclean · Post by **markmclean** » November 24th, 2005, 11:17 pm

Ahh but add that 30-40 hp to your newly installed klze and hold on to your hat...those mods apply to any engine from a 4cyl all the way to a big block race application, its just simple engineering. The point is adding power is rarely simple. Think the project through and build a car to suit your needs.