I just rode in a 386hp 8.5psi scion tc, which had the tiniest turbo I have ever seen. And the blow off valve was on the intercooler.. weird. Anyways, as soon as this car boosts, which there is virtually no lag time. All you hear is loud airy noise inside the car, from the wastegate. Inside the car, its louder than the exhaust or engine. I think this is kind of annoying. Do they make wastegates to let the air out with any less noise, or do all you turbo guys experience the same thing.

 

its not that the wastegate that is loud its that its most likely open dumptube, if you recirculate the dumptube back into the exhaust you wont hear the noise.

 

I've been in dual open dump cars that the wastegates aren't that loud (530whp twin turbo G35) so it's either the aim of the open dump, or just the fact that it's a compact car with minimal sound insulation.

 

The fact that the turbo is so tiny and the engine is so big (relatively) means he's bypassing the majority of his exhaust out of the wastegate, thus making it loud. When you have a B16 trying to spool a huge turbo to big boost, there isn't must exhaust to bypass so the wastegate is quieter.

My wastegate dump is deafening at spring pressure, but under normal, higher boost it's noticably quieter.

 

a 386hp scion on 8.5psi isn't running no small turbo............so i wonder just how many turbos the OP has ever seen.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by chimmike &raquo;</TD></TR><TR><TD CLASS="quote">a 386hp scion on 8.5psi isn't running no small turbo............</TD></TR></TABLE>

so maybe its not 386hp

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 91civicDXdude &raquo;</TD></TR><TR><TD CLASS="quote">

so maybe its not 386hp </TD></TR></TABLE>

186hp sounds more realistic. A tC isn't even making 386hp on 8.5psi no matter how big the turbo is, those motors just don't flow like that.

 

maybe it was 368, but he does have money, and it was a 6 grand turbo job, tuned with greddy by himself, so maybe his numbers are off, he said he ran a 12.8, i believe it, cause i was in my friends mach 1 stang, that should run at least a 13.5, and we could not catch him.

As far as the turbo the intake side and exhaust side was no more than a inch thick, and the width was about 5 inches. If i could compare turbo size, i would say it was the same size as a turbo on a audi a4.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by autoluder &raquo;</TD></TR><TR><TD CLASS="quote">maybe it was 368, but he does have money, and it was a 6 grand turbo job, tuned with greddy by himself, so maybe his numbers are off, he said he ran a 12.8, i believe it, cause i was in my friends mach 1 stang, that should run at least a 13.5, and we could not catch him.

As far as the turbo the intake side and exhaust side was no more than a inch thick, and the width was about 5 inches. If i could compare turbo size, i would say it was the same size as a turbo on a audi a4.

</TD></TR></TABLE>

I can judge more by his trap speed than his time. My Z ran 12.5's but trapped 115mph, which is good for 11s.

He's probably between 250-300whp. Which is respectable. Also, I've heard tC's have poor sound deadening stock.

 

depending on his trap speed he should be running alot fast than a 12.8 with 368whp

 

Scions do have an advantage with that big 2.4 liter, 88.5mm bore & 99mm stroke and 9:8cr - good for turbo, this could be why he gets the horsepower off that turbo like he does. + 4" exhaust. I dont have all this dudes specs,

and anyways, just wanted to know why his car was so loud on the inside, from the outside it rumbles like a wrx, could also be the turbo mani helping out with that sound. But yea, big engine, tiny turbo, that wastegate is always in action, usually ive only heard turbo whine, bov, and little bit of exhaust. this car was totally different.

Personally i dont care about scions. ha. , being an owner of 2 hondas....

 

Sounds like wishful thinking on the scion owners part, I would believe it if he had a dyno sheet otherwise I would be inclined to think he is more likely making 286.

The stock motor makes like 160bhp which means 136 at the wheels (likely). Now lets assume he makes 10whp per lb of boost that still only puts him at 221whp which in a scion (as already mentioned) is pretty respectable but he's not rocking 386 in it, and not at 8.5psi.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LudeLooker &raquo;</TD></TR><TR><TD CLASS="quote">Sounds like wishful thinking on the scion owners part, I would believe it if he had a dyno sheet otherwise I would be inclined to think he is more likely making 286.

The stock motor makes like 160bhp which means 136 at the wheels (likely). Now lets assume he makes 10whp per lb of boost that still only puts him at 221whp which in a scion (as already mentioned) is pretty respectable but he's not rocking 386 in it, and not at 8.5psi.</TD></TR></TABLE>

I wouldn't hold that as standard......I've seen a bit better myself in a lot of situations, especially on my turbo 350z. went from about 240whp stock to 379whp on 8psi. That's almost 140whp difference from only 8psi!

 

I loved my open dump. I wouldnt have it any other way. However, if you dont like it just reroute it into the exhaust like previously mentioned.

 

so what is this open dump, im not a turbo guy, but i see there is a round hole on top the wastegate, and i know its bolted on the exhaust manifold.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LudeLooker &raquo;</TD></TR><TR><TD CLASS="quote">Now lets assume he makes 10whp per lb of boost</TD></TR></TABLE>

Lets assume you know nothing about the hp/psi and just stop there. Thats not at ALL how it works.

Garrett turbos that "we" run just tend to have larger inlets and larger housings, so they look much larger. Some of the IHI turbos (WRX stuff) look very small, but can make quite a bit of power. It could be something closer to the size of a 60trim t3's wheels, which could get him 300whp at that pressure if the motor was perfect. I would just think its missing 75-100whp, since I've seen 60trim T3's spool fast and make close to 300whp under 10psi before.

A lot of newer/flashier car drivers use it as a means to impress, not necessarily to blow someone's doors off. I think this guy is just calculating BHP, and hoping the people he impresses dont pull the

 

Exhaust gas is used to accellerate (spool) the turbo's shaft. WHen it is going fast enough it will make a certain psi. At that point, it bypasses that gast around the turbo to prevent it from spooling too fast and making far too much psi. The wastegate & its dumptube is where this excess gas flows.

I recall some DSM owner welded his 14b's wastegate shut, and he hit around 27psi, then it dropped to 19psi at redline. Its kinda like a car's throttle pedal - you give lots of gas to accel, then barely any to cruise at a given speed. You are preventing the air from entering the motor, like the wastegate does for the turbine.

 

yea but wheres the tube, does it have its own exhaust pipe, does it come out that hole at the top of the wastegate, ...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HiProfile &raquo;</TD></TR><TR><TD CLASS="quote">

Lets assume you know nothing about the hp/psi and just stop there. Thats not at ALL how it works.

Garrett turbos that "we" run just tend to have larger inlets and larger housings, so they look much larger. Some of the IHI turbos (WRX stuff) look very small, but can make quite a bit of power. It could be something closer to the size of a 60trim t3's wheels, which could get him 300whp at that pressure if the motor was perfect. I would just think its missing 75-100whp, since I've seen 60trim T3's spool fast and make close to 300whp under 10psi before.</TD></TR></TABLE>

Actually to some degree that IS how it works, obviously it's not flat out _that simple_ but for each PSI of boost you should be able to make X aount more power as long as you stay within the efficiency range of that turbo among other things... All other things being equal each PSI of boost should bump you up the same amount of power until you are out of it's efficiency range.

Garret turbo's that "you" run? Oh you mean there are other F/I cars out there like VW and those guys sometimes run pretty small turbo's (K04s's and slightly larger) as opposed to the typical garrett GT28RS's and I am MORE than aware of that, what I am saying though is I have seen a few scion Tc's running F/I at 6-10 PSI and they make nowhere NEAR 386whp. I think the one I am thinking of was making like 230whp on 7psi or close to... So seeing as how 7psi with a good tuner got 230, I would like to see someone make more than 300 with less than 10

 

I have no clue about the scion motor but i saw a kit that is supposedly supposed to give them 300hp at the crank...but those dumptubes are built into the downpipe so idk. i feel like most scion's owners would buy a kit. ANYWAY i have a question. On my turbo accord, how far down should i have the dumptube reconnect to the downpipe? I heard you could get a turbulence kind of effect if it joins in near the start of the downpipe.