Custom exhaust gives 25~30HP to a 1999 Maxima?

Hi there, today I was talking to my friend about that a 1999 Maxima with an exhaust that still has CAT but no Pre-CAT, and he said this custom exhaust will end up give him 25~30HP at a certain rev range. Personally, I am highly doubt about it, what do you all think? I heard a lot of funny advertise about exhaust that gives 30hp, lol, but in a real world dyno, I barely see any single exhaust can give more than 20HP (maybe 5hp), do you all think it is possible? Since as I know, even a turbo can only give around 20~30HP more without any other modification.

Thanks

honnetement aprèes avoir swapper sr20det j'ai rouler un mois sur l'exhaust stock avant de mettre un 3pouces c dur a dire combien de hp de plus mais a haut régime ca parais en t****. selon moi 20hp de plus sur un moteur turbo mais ca reste a confirmer sur dyno!!

http://www.motorvate.ca/mvp.php/504

The question is yes but depends on the rpm range. Is it usable HP? Did you lose hp down low? Everything is a compromise. Don't forget that this guy lost hp down low. Everything in an exhaust is about air flow which is the speed of which the air moves in a given space. The better the flow the less power is wasted to get the exhaust out. Then there is the harmonics of the engine which aids in getting the exhaust fumes out. It is a complicated thing. "Usable" hp vs power you see on a dyno and in which application are variables that need to be attended.
This guy gained like 18 hp on average from 4000 to 6000 but the gain of 30 hp is from 6000 to 6200 rpm. Enough said he gained about 18 hp usable and 30 hp at higher rpm. Which you would feel mostly in top gear going close to his max speed. I this site the person had the following parts: y-pipe plus b-pipe are 2.5 inches instead of not even 2 inch depending on the bend and finally with cold air intake.
Yes I agree that most people BS to show off. Lastly, depending on the engine, depending on how restrictive,tolerances of the car from factory and the shape your engine is are all factors need to be factored in. There is no right or wrong answer. It all depends on many factors. This guy might have gained 18 hp but using the same pipe another person might have gained 10hp. Like I said it is a complicated thing and in this case not a yes or no answer. This is just my 2 cents.

Crazydrifter said:

honnetement aprèes avoir swapper sr20det j'ai rouler un mois sur l'exhaust stock avant de mettre un 3pouces c dur a dire combien de hp de plus mais a haut régime ca parais en t****. selon moi 20hp de plus sur un moteur turbo mais ca reste a confirmer sur dyno!!

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Sorry that I may not understand well French, but yes, as I know most of the Turbo engine will give you a good amount of HP after you swap to a reasonbly larger exhaust. But this example is about a NA 1999 Maxima....

To answer Lumlumty, yes, I understand that the 30HP you mentioned which happen only in a certain rpm, in your example, which is in between 6000~6200rpm, but still, I find it is more like an advertise result more than a real world dyno.

Another good example is, I had a magazine, which compare the engine of the G35 engine (2005 model 4drs) and the 350Z (2006 and up year) engine. Their engine HP different is around 20~30HP if I remember.... But what did they change? 1)Upgrade intake, 2)Upgrade piston 3)bigger Throttle body , 4)bigger header 5) an upgrade exhaust system 6)Update ECU. They are basically the same engine, but with these upgrades, it end up give only 20~30HP.

That make me wonder, a 1999 Maxima, with just a custom exhaust system, just without the pre-cats, and it gives you 30HP at high RPM? It sounds more like a joke to me, mostly likely an advertise thing. I remember I heard someone said "intake give you 20HP, exhaust gives you 30HP....." well.... If you believe this, then you should already have 50HP.

if the whole line is 2.5" your looking at a maximum of 30hp.this guy http://www.motorvate.ca/mvp.php/504 has the stock cat-back 2 1/4".the VQ30 was and still is in many peoples cars a Restricted engine,changing exhaust to an engine like that can have crazy results....I hope cause im installing my warpspeed 2.5" y-pipe and custom 2.5" cat-back this week on my 98 5spd...ill repost with the info..BTW hi-flow cats are bullshit they all do the same........


The VQ is a seven-time winner of the "Ten Best Engines Award" presented by U.S automotive journal Ward's Auto World.With that crappy stock y-pipe!!!!!!!!!

That is a dyno graph from the vendor right?

I know Maxima is a pretty good fast sedan and it has a very good engine, but gains 30HP from just an exhaust with a NA Maxima? I highly doubt it.

Lumlumty, ask yourself, do you feel 18 or 30HP gain since you had this exhaust installed? I drove it before and after, and yes, I can feel the car runs smoother, louder and maybe a bit quicker than before, but honestly, I don't feel any 30HP nor 10 HP, and when we tested your maxima before with my G-meter (G stock like device), you already know that the 0-60 time is just a margin faster or same as what people or magazines claimed as a stock automatic Maxima. I know your car is old (1999), but still, if the exhaust is that good, the 30hp should at least help you to improve a good 0.5sec, but it didn't.

And blkcivic00, if possible, can you f post a before and after dyno graph after you had the exhaust install? that will be much more clear.

and here it is a good info about exhaust system"http://www.geocities.com/MotorCity/7177/exhausttheory.html"

"Do Mufflers "Make" Horsepower?

The answer, simply, is no. The most efficient mufflers can only employ the same scavenging effect as a header, to help slightly overcome the loss of efficiency introduced into the system as back pressure. "So," you ask, "what the is the best flowing muffler I can buy?" "

The dyno graph shown is not a dyno graph from any company.
Well no you are missing the point here totally. 0-60 times are not the best to base performance even if this is the industry standard. 30 hp not at peak power band would not be the same if the 30 hp is across the board. the "usable" hp is at the end of the rev range would only yield modest results point final. the 30 hp you are talking about is at peak or across the range. The person only gained average of 18 hp from 4000 to 6000. The bases for conclusion on the previous reply is not sufficient by just quoting the muffler part. After reading the site this is what I have.
Each engine is different. The part where you quoted is based only on mufflers not the whole exhaust. The mods on the movat site are y-pipe, b-pipe and intake not only the muffler. If your definition of an exhaust is the muffler then yes you are right. read what he says about headers and look at where the y-pipe is situated and you will see that this is almost considered to be part of the header. They the header is part of the exhaust since it is used to exit gases from the engine then why did bmw came up with 14 different heads for the e30 M3? the site even mentions a thing or two about 4-1 headers. As stated in the previous reply it is not all that simple.
Read the site in more closely and in its' entirety. read the movate part where he explains why the y-pipe works for the Maxima.
Yes blkcivic00 the Maxima exhaust system is restrictive from the factory and therefor these gains are not uncommon with the movate setup the cat yo might get .5 to 1 hp woppy

lumlumty said:

The dyno graph shown is not a dyno graph from any company.
Well no you are missing the point here totally. 0-60 times are not the best to base performance even if this is the industry standard. 30 hp not at peak power band would not be the same if the 30 hp is across the board. the "usable" hp is at the end of the rev range would only yield modest results point final. the 30 hp you are talking about is at peak or across the range. The person only gained average of 18 hp from 4000 to 6000. The bases for conclusion on the previous reply is not sufficient by just quoting the muffler part. After reading the site this is what I have.
Each engine is different. The part where you quoted is based only on mufflers not the whole exhaust. The mods on the movat site are y-pipe, b-pipe and intake not only the muffler. If your definition of an exhaust is the muffler then yes you are right. read what he says about headers and look at where the y-pipe is situated and you will see that this is almost considered to be part of the header. They the header is part of the exhaust since it is used to exit gases from the engine then why did bmw came up with 14 different heads for the e30 M3? the site even mentions a thing or two about 4-1 headers. As stated in the previous reply it is not all that simple.
Read the site in more closely and in its' entirety. read the movate part where he explains why the y-pipe works for the Maxima.
Yes blkcivic00 the Maxima exhaust system is restrictive from the factory and therefor these gains are not uncommon with the movate setup the cat yo might get .5 to 1 hp woppy

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Um... First, the dyno graph that you both show is a dyno graph that only showed within a vendor site, that is what I meant.

Please refer back to the same vehicle, otherwise, it will be kind of off topic. Not even mention that we are not talking about header here.

Nope I don't mean that 0-60 is the only way you can tell the different, but it is one of the way you can tell the different by compare your car. On the other hand, you can always test your car though any Dyno in MTL.

Though the graph, it shows around 25~30HP starts from 5000RPM if you look at it carefully, and yes, the peak HP is 30 at 6200rpm, but tell me, do you feel that much power from 5000rpm? Do you really know 20hp 's gain will give you a very noticeable feeling, but not just a drone sound from the exhaust.

The site I post before gives you an idea, that if you have the whole header and exhaust system installed, it MAY gives you a performance gain, but again, we are talking about exhaust system only, right? Don't suddenly tell me that HP include air intake and header or whatever all of sudden.

As I said before, so many vendors use different ways to prove HP gain from their exhaust or header. I remember that the magazine SportCompactCar did test some of the most famous header and exhaust system before, which include the Mugen header and exhaust, it finally comes out with no or a ~5HP gain with like Mugen, DC or whatever combo of header and whole exhaust system, which again some people claims they give 30HP or more from different advertisement.

A good example is, within the Hong Kong car magazine "option fans", it shows a dyno graph that several exhausts (stock with just exhaust) and made 20 ~ 30HP for Mini Cooper S. Should I believe the graph? No way, but I can still scan and post it out to claim it is not from vendor but from a tester.

Btw, Lumlumty, I really don't mind to share a dyno fees with you by see the different of your stock vs custom exhaust, if you want, we can do it at anytime. But just, ask yourself, have you ever see that HP gain after the exhaust?... If you ask me, last time when I floor your car till redline, I can only tell a small different like 5~10hp max, and that is it.

30 hp gains are very possible but only with a cold air intake, and a full exhaust including y-pipe and all 3 cat delete.... like was posted earlier, the stock maxima exhaust had allot of restriction, especially with the 2 pre cats on the y pipe....

the most power gains come from the y pipe....

MOBMAN said:

30 hp gains are very possible but only with a cold air intake, and a full exhaust including y-pipe and all 3 cat delete.... like was posted earlier, the stock maxima exhaust had allot of restriction, especially with the 2 pre cats on the y pipe....

the most power gains come from the y pipe....

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thank you mobman....are you really a mobster?????LOLjoke.
i know maximas have about 165-170hp at the wheels stock...now ill find out how much i have at the wheels....CAN'T WAIT!!!:run:im gonna check out technika cuz their dynopak is more precise then a roller dyno.........

I have a 96 maxima se with a few mods cold air, y pipe, exhaust and a couple other small things..... I pull 15 second quarter miles and better very easily with 2 passengers and a full tank of gas and winter tires.... and over 500 000 kms... I think you should be around 230 hp at the crank with the intake and exhaust!:yikes:

on my ex 2001 I installed a Y-pipe, INJEN CAI and UDP and I definitly gain some respectable hp (but loose some torque).

You can esyli get 15hp with only a Y-Pipe on a maxima, and up to 30 with a CAI and hi-flow cat

blkcivic00 please show your graph when you are done. I hope you are not working for a vendor or affiliated with a manufacture. thanks

Yes exactly at high rpm 30 hp when compared with the graph prior to the mods.
Please if one of you guys do a dyno run before and after please do post it here.
I am not living in fantasy land and the dyno does not lie. The 30 hp is near the end of the rpm range of course is not going to give you the oohhmp that you are going to get if the 30 hp is more spread out. I hate to repeat this is a quote from him.

how big different is a 30HP? You can tell from mine and old Mini S. It is a huge different (more than 1.5sec faster), plus, again, not the whole range increase, but 30HP at 6k rpm, and this is after intake, SC pulley and exhaust, and as you know, my JCW is also a pre-CAT delete type.

No the JCW is NOT the pre -CAT detete type. It is after the Cat this is for sure just look under your car and you will see I am the one who picked it up and I was there when it was installed.
hmm better yet look at this link. Is that a resonator I see? it goes after the cat.

http://www.webbmotorsports.com/howto/images/fa83bc31.jpg

Please Your 30 HP increase at 6000 rpm is not a good indication. How much is gained from when the SC kicks in until the power tapers off will give you a better indication on how much you have gained with your modifications when comparing with the old graph. Just like the website you quoted from you need to look at the bigger picture. Each car is different in design, the condition of the engine, etc
I feel like I need to repeat myself but the point is in the Maxima's case the numbers are possible.

Please you are telling not to use other cars as examples yet you use the information regarding the performance figures. I just mentioned that BMW have 14 headers for the e30 m3. I didn't compare performance figures.

It really depends on the design of the engine. If the oem components on the car is good to begin with then your gains will be less.

Lastly the numbers on the movat site is based on a manual car I have automatic so the gearing is different 5 speed vs 4 speed. The gains on my car might be less who knows. All that I know is that other people have similar experiences. Man just hear me out. The truth is in the sites you showed me.
I never said that my car experienced the same gains but the parts mentioned do have the capability to get the results shown in the movat site

Id say maximum 15 to 20hp more with an intake and a complete exhaust system...

si je peux me permettre.. ok, j'ai pas une Nissan.. surtout pas une Maxima.. J'ai une foutue Camry

Mais ma camry, je me suis fait faire un Y-Pipe en Stainless 2"->2.5" custom par un gars bien connu dans la scene des Camry (Toysrme) aux usa.. ca donne ~25hp.. faut s'entendre que le Y-Pipe d'origine cree beaucoup de restriction parce qu'il est ecrase pour passer en dessous le subframe pour aller au cataliseur.. Et comme toute bonne camry qui a eu droit a un battage regulier.. mes 2 flex ont lachés a cause de la pression et mon auto fait du bruit comme c'est pas permis.. (J'devrais le recevoir dans les prochaines semaines, ca va faire du bien a mes oreilles et a mes voisins )

Des gens qui ont fait un Y-Pipe 2"->2.5" ou full 2.5" pour leur camry ont testés ~25 hp sur des dyno a compare un Y-Pipe OEM.. on s'entends aussi que leur moteur a surement pas 305000km au compteur

Donc.. ~20-30hp sur un VQ35.. je serais vraiment pas surpris

Hi lumlumty:

Well, first, yes, please, if someone here can prove that only the exhaust itself can gives a good 30HP, please show me the dyno graph. Again, this is a claim of "The exhaust itself gives 25~30HP" by remove Y-pipe and a custom exhaust. Don't tell me all of sudden, it does include intake, head, header this and that, which is kind of off topic.

Second, as for the JCW exhaust on a Mini cooper is just an example, if you compare the JCW exhaust to the stock one, the stock Mini S exhaust has a very restrictive route by take off noise and keep the torque at the same time, yes it is my mistake that I forgot the stock S exhaust has no front resonator, my bad, but check here (http://www.sunshineminis.org/forums/viewforum.php?f=30) the owner of this forum sold the resonator delete pipe, ask him if it makes any HP? None or 1 HP maybe, but sounds meaner, that is it. But again, the reason why I use this example is , even I change to an exhaust which most people swear it gives 10 or + HP, but JCW itself claims, it just makes the car run smoother but maybe 1 or 2 HP. From your previous post, when you use the example for an E30 with 14 kind of headers? Which I think is not related? And after all, my example was send to you by PM, so it is not for this topic... Can you tell me how can it be "Off topic"?

and from this link (http://www.dragtimes.com/Nissan-Maxima-Timeslip-2527.html),
this is a fully modified Nissan Maxima 1997 (still NA and take off almost all the interior , only 2800LB with driver) it makes a good 196WHP, if you calculate the 15% power loss from wheels, it comes up to around 230BHP. Stock Maxima 's WHP is around 160~170WHP, and 190BHP. So for this fast and fully modified Maxima, after this guy spend all his money and mods (include the Y pipe and exhaust), he only made a shy 10WHP or 10BHP more than what you mentioned, just the whole Y pipe and exhaust gives 30HP? So, his ECU, intake, header, all other mods only give him another 10HP?

As I know, NA car is always hard to boost extra HP, but yes you still can, but they will never be like Turbo or any other F/I type car, which an exhaust may gives 20 or up HP.

For the link I post earlier, about "Muffler makes no HP", yes it does mentioned that a complete intake and exhaust system may gains performance to car, which is true, I never say it will do nothing, but again, with just an exhaust, no way to give you 30HP. It also quoted that yes, for a turbo or F/I cars, you can expect a good gain of HP.

Again, at the end, once again, we are talking about the custom exhaust itself, so please do not add something else into it and claim it is possible, thanks.

theoutsider said:

Id say maximum 15 to 20hp more with an intake and a complete exhaust system...

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Thanks for a more reasonable comment from a Maxima owner. *tu*

" am I really living in fantasy land" with no proof?
The dyno graph shows improvement at higher rpm.
So from 0 to 60 half a second is about half a car length if you talk to any racer that is a lot.
Like I say before it really depends on the car. Not a yes or no answer all the time.
the 30 hp gains are not usable hp. The facts are there just read it. I am trying to be politically correct but you just don't admit it. no one is always right. In this case the proof is in the numbers on the graph and judging from your g-tech .5 seconds
Which is half a car legnth is about15 to 20 hp increase. This proof is also substantiated wit hthe graph on the motorvat site 18 hp from 4 000 to 6000 rpm. so don't even quote theoutsider.

theoutsider said:

Id say maximum 15 to 20hp more with an intake and a complete exhaust system...

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Because what he said is right. 18 hp is on par to what theoutsider is saying.
I mean what the hell can 30 extra hp do when it is only 500 rpm until cutoff?
What is more important is the 4 000 to 6000 gain. So don't even concentrate on the 30 hp anymore. I have stated this from my first quote it is the average from 4000 to 6000.
Is this this enough proof? Please read your web sites you quoted in its entirety, the motorvate site and yes the comments from people who contributed in this discussion. I am just trying to be politically correct here. What is right or wrong the reader will need to figure out.
No one is living in fantasy land here. 18 hp across the board is a reasonable gain. The 30 hp from 6000 to 6 400 rpm is all fluff which is what I said before.
Not that simple right?

lumlumty said:

" am I really living in fantasy land" with no proof?
The dyno graph shows improvement at higher rpm.
So from 0 to 60 half a second is about half a car length if you talk to any racer that is a lot.
Like I say before it really depends on the car. Not a yes or no answer all the time.
the 30 hp gains are not usable hp. The facts are there just read it. I am trying to be politically correct but you just don't admit it. no one is always right. In this case the proof is in the numbers on the graph and judging from your g-tech .5 seconds
Which is half a car legnth is about15 to 20 hp increase. This proof is also substantiated wit hthe graph on the motorvat site 18 hp from 4 000 to 6000 rpm. so don't even quote theoutsider.

Because what he said is right. 18 hp is on par to what theoutsider is saying.
I mean what the hell can 30 extra hp do when it is only 500 rpm until cutoff?
What is more important is the 4 000 to 6000 gain. So don't even concentrate on the 30 hp anymore. I have stated this from my first quote it is the average from 4000 to 6000.
Is this this enough proof? Please read your web sites you quoted in its entirety, the motorvate site and yes the comments from people who contributed in this discussion. I am just trying to be politically correct here. What is right or wrong the reader will need to figure out.
No one is living in fantasy land here. 18 hp across the board is a reasonable gain. The 30 hp from 6000 to 6 400 rpm is all fluff which is what I said before.
Not that simple right?

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Lol, guys, can anyone help me to translate what he said? Unusable 30HP, but usable 18HP....

Again, the only proof you had so far, is from a vendor site, I already post a real world dyno (a very fast Maxima with almost full NA mods) can make around 190WHP ~.

read this forum, read the second post from this expert, I am not a good person to explain thing, but here we go (http://ca.answers.yahoo.com/answers2/frontend.php/question?qid=20070630202452AAfk5lZ)


". By adding mods like the y-pipe and intake you are actually making the engine more efficient in producing power, the keyword there being efficient. You can actually mod your car to get more power and increase fuel efficiency as well. You do use more fuel when using the extra power (i.e. heavy/full throttle), but with the engine breathing better and being more efficient you use less fuel at partial throttle. Most don't realize that you are only making maybe a few horsepower under partial throttle when cruising."

Btw, Lumlumty, when and can you tell me when did we test the 0-60 right after you had the exhaust installed? If I remember well, after all, hope you don't mind I post your time here;

After your intake, underdrive pulley and the Y pip + custom exhaust, your average time was 8.2sec.... Yes, we did it only once 7.6sec, but since then it never happen anymore. Again, before the underdrive pulley, your car constantly run 8.x sec, and the 7.6sec only happen once after the pulley installed.

So when did I or we see the 0.5 sec improvement though your exhaust?

Please, this is not sth personal, but just a fact to show that an exhaust won't give much HP for a NA car, and the previous Maxima owner claims 15 - 20HP MAX is a reasonable claims, which is not the same as you mentioned.