Hey guys I was just wondering if a larger exhaust will give more power for the Vortech/Procharger Kits? I'm debating on either the HKS/X02 which is a true dual exhaust or something like the Tanabe which is single midpipe and muffler.
Are headers worth doing in terms of power gains. I know on the Stillen website they advertise not to add headers to their kits but I don't think that would apply to the centrifugal blowers. From what i've seen headers will make nice power especially on boosted set-ups but I want to hear some different opinions.
Also, with 8-9 lbs of boost through the Centri's would the difference in power be significant? Thanks for any and all input.

 

no, they need more backpressure than a turbo setup.

 

well if you have stock camshafts you need backpressure or else you will be leaking boost, but if you have aftermarket cam's you can have bigger exhaust.

 

So basically I can go with a single midpipe style exhaust and I won't be losing out on any power?
How about the headers? I see lot's of Vortech guys with headers.

 

you can do whatever you want, but if you go too big, you'll lose a lot of your low and mid range power

an X, H, or Y pipe design will show more benefit with a vortech/ATI than a true dual.

IMO cams is just another piece of the total exhaust throughput. Going with bigger cams doesn't really mean you should automatically go with a larger exhaust. Actually for most people's power levels, I'd argue they're better off staying with a decent medium size exhaust if they have aftermarket cams

 

Sentry answers all.... Thats prob in the vortech FAQ's also..

 

This question comes up many times and answers are given w/o benefit of a legitimate/reliable informative recognizable source..Any one wanna point to a source or an article that specifically speaks/relates to a S/C and the affect exhaust size has on power.? Please no anecdotle stories..Real facts..

 

to explain in simple terms think of a water hose. put your finger all the way over it and you not much comes out. take it off and it just kinda of falls out. now if you put your finger over it but still allow flow the velocity increases and the water moves out quicker. and when you turn up the water then you need to find the spot again were it shoots water out quickly to compensate. an engine can be looked at in the same way. you want to dispel exhaust gases with maximum velocity. so a really small exhaust is restrictive like putting your finger over it. a really large exhaust is like taking your finger off the hose. as rpms increase the amount of exhaust being dispelled at a time is greater so its like turning up the water. the idea is you want maximum exhaust velocity to achieve the best gains. so for your setup you will want a mildly sized exhaust. adding cams wont really increase how much exhaust gases youll be moving. most N/A cams which is what you want for a s/c are more biased to intake. hope that helps.

 

Comparing the dynamics of a combustion engine to a water hose? Like I asked, no anecdotal stuff, lets see some real data that relates exhaust size to engine performance for S/C's..

 

we have tried many different combos on all different kinds of Vortech setups. the only thing you will do is really lose low end tq. its pretty much going to make roughly the same power on stock exhaust as it will on true dual 2.5 inch. the cats however matter a 10-15 difference on average when switching over to test pipes. i wouldnt worry too much about the exhaust though. we have wasted many of hours trying to make more power.

change the pulley and it will work every time...

 

Thats not true..int/ext valve lift is increased(and stay open longer) allowing more air to enter the engine as well as leaving the engine...

 

you should just do some of your own reading. I'm just offering what I've experienced first hand as well as read on the net from others with all makes of cars. Go on the mustang or vette forums and look at their experiences with vortechs and exhausts since vortechs are popular there. I don't think you'll find it differs a whole lot from what me or jeremy@pf have said, nor do I think you'll find a whole lot in terms of scientific data sheets about exhausts with centrifugal superchargers, but I could be wrong

a true dual will allow slightly more top end power at the expense of low end power. Having an X, Y, or H pipe connecting the two sides uses one side's pulse to help suck the air out the other side when it's between it's pulses. They have their pros and cons. H-pipes usually offer better low end power and compromise the top end slightly, while X and Y-pipes are a little better for top end power. NASCAR uses X-pipes. From my understanding it's always beneficial to have the two sides connected at some point unless it's a turbo car where you want absolutely as little resistance as possible

 

you're both right and sorta wrong

that's true that more air would enter/exit an engine with aggressive cams than with normal cams - at high rpms, however at high rpms there's less time for the air to enter so you end up with less air per engine cycle. That difference in lost power per stroke is made up for by increasing the rpms so those weaker combustions are happening more often.

What I'm getting at is there's only so much air that will naturally fill up a cylinder chamber - unless you compress the air via FI

 

Sentry,, lots of people on this forum are making some expensive decisions based on what others say , but offer no real data to substeantiate there opinions..Lots of anecdotal stuff like your response above but no first hand unequivical data that substantiate what is being said.. Ever hear the phrase "In god we trust, others bring data"? If you or anyone else has a dyno of before and after (Stock vs a dual or anything else ) your stating an opinion based on what others may or may not have experienced..Do you have a dyno #'s on what you say you experienced to help here?

 

yeah I did have dynos from my car when I changed out my exhaust from a nismo to a modified APS with X-pipe along with some other things. I'm just not going to go to the trouble to find them just for you when I've already posted them before etc. They're not exactly perfectly scientific though since they were done in different weather, and there were some other minor parts changed as well

My opinion on the matter is based on the data I've seen over the years. I used to save everyone's dyno and basic car info to these HUGE photoshop files where I normalized all the charts. Together I have over 400 dyno charts saved out in this file.

You easily start seeing patterns after awhile when you start collecting a lot of dynos. The results aren't always going to be repeatable on another car. Some guy could change his exhaust out, but what else does he have on his car? If you get the same exhaust, you probably won't get the same result unless you match the rest of the parts. So the best you can do is look for patterns over a huge collection of data because one, two, three, or ten dynos isn't going to really be enough to paint an accurate averaged picture

Most of the data you're going to find is where someone posts their dyno from awhile ago from a different season of the year and the new one after they changed a few things (not just exhaust) and retuned. FI People just don't bother to spend the money dynoing and retuning over just an exhaust change unless they're turboed where an exhaust can make a massive difference. Most SC people usually end up doing a combo of things like pulley, injectors, exhaust, headers all in one go so their money is being efficiently spent on a new tune.

Anyway, take it or leave it. I'm just trying to save you the trouble of looking things up yourself. I've seen enough dyno results from others including myself to know what generally is probably going to happen with different exhaust setups. Jeremy has also said what he's generally seen happen at his shop on his dyno over the years.

The total flow is what's important. You could have cams, headers, stock cats, and exhaust that overall flows the same as a car with stock cams, stock headers, test pipes, and exhaust. The dyno curves can still end up being fairly similar even though totally different parts have been modified.

 

When I had my procharger with borla and tp's no cams I got 352whp & 312wtq on 7psi. I realy miss the sound of that blower but love the feel of the turbo now.

 

Sentry say's:

"you can do whatever you want, but if you go too big, you'll lose a lot of your low and mid range power

an X, H, or Y pipe design will show more benefit with a vortech/ATI than a true dual.

I say show me and you say I won't..I have dyno's but I won't show you.

It's not just me it's the many many posters that have asked and will continue to ask...

Nice guy you are..

 

i went pretty big when i had my procharger and lost a ton of low end tq/hp...i had strup headers,2.5 inch downpipes, aam dual 3inch exhaust....got max top end but when i look back on it...prob wasnt worth it...
get a nice cat-back and maybe some high flow cats....have some back pressure and like jeremy said....all u have to do is change the pulley to make up for the lost powa

 

Ok, then how would you like me to send you a 90 meg grayscale photoshop file?
I have 6 other smaller ones as well. Not just Z dynocharts, but other cars as well with various mods.

Where do I send them?
Do you have an FTP I can send them to or some web space somewhere?
Do you use AIM?
How about I break them into a bunch of 5 meg zip files and email them to you, or will that be likely to suspend your email account?
Do you even have photoshop in the first place?

or do you really expect me to post over 400 dyno charts...?

They really should just stay as .psd files because the layers are just isolated curves by themselve with the blank graph showing through on the bottom layer


....I thought it'd be easier if I just shared my conclusions from staring at and comparing all these charts over the years

 

Yes please.