Garage1217

iTrader: (5)

You did not "loose boost" at all. The header she had must have had to much backpressure that the engine starting flowing allot more air. That would not equate to a loss in HP.

OutCrnrU

ok time for me to chime in a bit.

My dyno was pre-intercooler. I do not yet have a new dyno as I am trying to recover the boost I lost due to the intercooler and the length of piping involved. I should have an update for everyone by the end of the month.

As far as the header issue. Anyone who knows anything about boosted cars will read this thread and have a heart attack. If a header makes power on an N/A application, why would it lose power on a forced induction application?? I have no doubt in my mind that if Lundy put on a header with his current unichip tune, he would gain power. His power gains over everyone elses come strickly from the unichip tune. He is trying to say that if he put a header on his hp would go down, not likely. Lets say stock gave him 195 SAE corrected whp(about average from what people are getting). add the 21whp from the zpi pulley and you get 216whp. It is very VERY possible to get 20 some odd hp just from tuning the ecu nobody is arguing that fact. Lundy is trying to say if he put the header on he would lose power, which im willing to bet he would gain power, especially above 5,000 rpms. Yes maybe he would lose a little torque, but that does not justify not using a header like he is claiming.

Take my setup for example. 224whp with a header and exhaust. I would be willing to bet if i put the stock exhaust manifold on i would lose hp, maybe gain some low end torque. Also if i took that same 224whp and dyno tuned it with a unichip, i bet i will get more than 236whp.

Its all in the way you look at it, but the evidence will prove that using a stock exhaust manifold will not yeild more hp than an aftermarket header. I know this may have been a little confusing, and i dont know everything about everything, but the numbers just dont add up.

No one on this earth who is an experienced tuner would use a stock exhaust manifold over a header, especially in a supercharged car, period.

HighlanderMac

OK.. well, we will have to see what I end up dynoing when I finally get back to the same place. I dynoed 227hp and 197ftlbs BEFORE my header. WITHOUT and Intercooler, So when I go and dyno again, we will see if I lose anything.

I am still waiting for a dyno, I would just like to look at it.


Oh and one thing you have to also see is that my tC dynoed higher than any of the other tCs with the same mods, and I have a 3" exhaust, SO I should have ALOT less backpressure...

And here is my Dyno:

zer0

No power was lost, but the 4psi pulley was no longer boosting 4, the headers cut it down to 2psi. The boost #s may be lower, but she is flowing more mixture through the engine than before, which will obviously yield more power.

Garage1217

iTrader: (5)

exactly Now you can go buy the sc, it is capable of 250whp, it is capable of 350 or so. It is an f-trim vortech good to 20 psi max. She is capable of throwing your rods through your block with ease.

kungpaosamuraiii

Forcefed is saying just that -> a header will cause boost lost.

But why is that? On a roots type, why does boost go down with a header? I don't understand engines enough to know why, please explain .

Simplyscion

possible belt slippage from the added power of the header??

ForceFedRacing

To clear some things up let me state more clearly what causes loss on a centrifugal blower and what does not. A simple misunderstanding is preventing alot of people here from understanding what actually causes the loss. It is NOT the header itself that cuases a loss of backpressure and therefore the power loss but it IS the CATYLTIC CONVERTER that causes the loss of power when removed on Centrifugally Supercharged engines. This is not conjecture , this is something that you learn when you go through a Centrifugal supercharger installation course like we did with ATI (Procharger) and when you take a course on ICE Physics ( Internal Combustion Engine Physics). Much confusion comes from inter-relating the power loss/gains of a turbo charger with decreased backpressure and a Centrifugal Supercharger system experiencing a loss of back pressure. A turbo many times will see both a loss and a gain of power when a 'cat' is removed. Usually a loss of power is experienced at lower RPM's because of the fact that the lack of backpressure or exhaust energy being multiplied by density is decreased due to the lack of resistance in the exhaust path. This is usually made up for when the wasted exhaust energy being released from the turbo is able to move quickly , with little resistance out of the exhaust system , allowing for an increased rate of power as long as resistance stays low. The difference with a centrifugal supercharger is that it is designed to work with factory "cats" and therefore factory energy release and flow levels. When that flow is increased on a Supercharger than resistance is decreased and since centrifugal superchargers get their power from resistance , the lack of it can and usually does not allow the blower to work at max effeciency. A simple remedy is to purchase a header and make sure that a "cat" is left inline to keep up backpressure and therefore the all important resistance.

I hope this helps. I will post some before and after dyno sheets of our 9psi kit soon so that everyone can see what the ZPI 9psi pulley does on both factory and aftermarket tuning. One thing to avoid that I have noticed people doing is adding hp numbers together to figure out how much more power would be gained by different combinations. This is completely inaccurate. We gained 25whp with the increased psi from the ZPI 9psi pulley giving Justins Tc 183.4 uncorrected whp. We then tuned it with the Unichip and gained basically 29whp giving him 212.2whp uncorrected! So basically you can expect that with a proper tune you can gain on average 29whp. The Unichip is one of the worlds smartest and smallest learning computers. Using patented technology they have been able to achieve what many have not. Hope this helps![/i][/b]

PghtC

PghtC

yeah but there are no headers that have a cat incorporated.


not anymore at least.

Munch

I agree about the loss of lowend power when swapping out the stock header for an aftermarket unit. I experianced this with my supercharger setup. I added a high flow cat and gained it back and felt it immediately.

PghtC

you added the high flow cat where? Where the second cat used to be, or in addition to the second cat?

Simplyscion

in replace of the stock cat

Scion-ce

Will a high flow cat in the midpipe be enough to regain low end power, or does it have to be in the header itself?

Munch

I have the 2.5 inch Megan Racing catback exhaust. It eliminates the second cat, so I had no cat on my car at all. So I added a Magnaflow 2.5inch high flow cat just before the resonator. Picked all of the lowend I lost right back up, and it also made the car sound a lot better. It was just way too loud without it.

zer0

Munch, you gonna share how well you did with the supercharger and unichip? #'s?

Simplyscion

whats the point...you know everyone is gonna come on here and knock it anyay

Munch

Couldn't have said it better myself . Sorry bro, but I won't even open up that can of worms. Its been nice and quiet here lately hhahahahaa.

DTRUONG_112

So why did you go turbo now when you said you could take stage 0 tC-t's? If your SC was putting down good numbers, why getting something else that can perform as good as the old setup?

Simplyscion

lets put it this way...the way I sit right now with my supercharger, I will walk on stage 0's all day long...I dont care who is driving the car, I will beat them time after time. On another note, the way my car sits right now, I cant beat stock Evo's or Sti's but the turbonetics kit will. I think by the end of this week I will be able to hang with them, and when I get my clutch and flywheel in next week, I really will be able to hang with them if not beat them by a car or so.