turbo maxing out?? efficiency??

[siregcivic]

ok.. well i have noticed that when im pushing it.. it makes nice power from 3k to 65-6700 then it feels like it stops making power above that...not like it falls on its face or anything.. it feels like the powerband hits its top at 6700 then starts flatening out

is the turbo i have not that good for upper rpm range??

its a t3 .42 .48 off a saab

[JoelAllenClear]

You have assumed correct. The powerband does flatten out after about 6k or so. Get a .60 cold side conversion and you'll be feeling a bit more power.

[siregcivic]

You have assumed correct. The powerband does flatten out after about 6k or so. Get a .60 cold side conversion and you'll be feeling a bit more power.

ok sweet thanks man...

would u happen to know where i get the conversion from?

[myHonda1]

my t3 does the same thing at about 6500 it smooths out. none the less i still love it!

[Slowhatch]

would u happen to know where i get the conversion from?
x2

[überTUNED]

T3/T4 conversion for sho... i like running the .57trim 63 A/R myself...

[konigcivic]

maybe its your tune. some tuners make it more aggressive up top with advancing timing after peak torque, some dont.

how much boost are you running, and what whp are you at? without at least that info, how can anyone on here say its to small of a turbo?

[csaddict]

Maybe its your exhaust. What size down pipe? Run a cat? What size pipe? My first setup fell off up top. I switch to a 3" DP, 2.5" exhaust and no cat. Bang full pull!

[Dweezil]

Maybe its your exhaust. What size down pipe? Run a cat? What size pipe? My first setup fell off up top. I switch to a 3" DP, 2.5" exhaust and no cat. Bang full pull!

I'd start with the same thing. Make sure you don't have a huge restriction past the turbo first. If that's not enough then go to a larger housing or exhaust wheel.

[siregcivic]

its street tuned.. idk how much hp.. 10 psi on the street 12psi when i race

its 2 inch dp (homemade) to a 2 1/4 exhaust hallow cat with a resinator and muffler.. wich i wanna take off the resinator when i go 3inch piping... i wanna buy a dp but dont know where so i made one using the stock flange.. i cut the stock flange right at the turbo and welded the pipe on...

i was thinking also maybe the exhaust pipings too small.. its my first turbo setup so imgetting used to it on upgrades and stuff

[Dweezil]

I'm sure if you got the flange from anywhere and took it to a competent shop you could have one made. If you can weld just buy a flange and some mandrel bends and go to town.

[The_Acid_Beaver]

That 2" DP and 2.25" exhuast are really restricting your turbo. Do you ahve an intercooler? If so, how is the piping run? Long piping kills flow. Keeping your intake short will let your turbo breath better and help raise the roof of your power production some.

Just for the record, you want LESS timing advance as the RPMs increase. This is because the engine is rotating faster so the time it takes for the combustion even will have to occur later in the compression stroke or the piston will be moving upward into an expanding volume of gas produced by the air and fuel bruning too early. This fight through the expanding gases slows the pistons upward movement, preventing your engine from using that expansion to push the piston down, turn the crank, and eventually, drive your wheels.

[siregcivic]

i have a front mount intercooler... it comes off the turbo 90 degree turn towards the left wheel. then a 180 around the rad support to the ic then theres a 90to a 90up through the hole to a 45 to a 45 to the tb... i know that sounds confusing as hell but im sure u get it

the charge pipe is 2inch id the tune is setup to pull 1/2 degree of timing per psi i love it either way.. idk.. maybe its just cuz im so used to taking it to 8.5k all the time all motor.. but it has hella more power with the turbo.. i think im just being greedy.. it pulls all the way to 7.5k but it feels like the powerband has maxed out at 6700.. maybe thats normal i know i cant have the top of my powerband at the governer witha stock motor and turbo..

anyway.. ill be getting a dp made.. what size should i get, then im gonna get a 3inch exhaust...

thanks for the advice/help.. im still newb to the turbo setup so im just cruising along slowly on the upgrades and getting everything setup better:TU:

[X292J]

My car dose the samething, i sure its the engine (it being a D). Even with a psi change the power just carried over at a certain point. At the time it was 6500 to 7200 for me on my d15b7.

just for refence i use a twin scroll T3.T4 with a 3" open down pipe.

[94z6ex]

i think you should upgrade to a least a 2.5" DP and exhaust....maybe even a 3" exhuast, because your going to need to realy bad of you go ahead with the .60 conversion. but get it out of the way, you may not need to get the conversion for it, but im guession that you will still need it.....which means you will need a retune.

but i would try getting a less restrictive exhaust flow to free up a few more ponies and so the turbo can breath better at those high rpms.

[The_Acid_Beaver]

I wouldn't run anything less than a 3" from the turbo to the tip.

[siregcivic]

alrighty... acid u think 3 inch is ok from turbo to tip??? ill order a t3 dp flange and have my exhaust shop make me a new exuast...

[X292J]

... my point being that the engine runs out of breath at a certain rpm.

Its best to shift and drive your car in the productive RPM range where it is most efficient.

[JoelAllenClear]

Maybe its your exhaust. What size down pipe? Run a cat? What size pipe? My first setup fell off up top. I switch to a 3" DP, 2.5" exhaust and no cat. Bang full pull!

Full pull even with a T3 .42/.48 ???

:TU: This guys experienced!

[Jcazz]

upgrade your down pipe to 2.5 or 3 inch....and Exhaust shouldnt be less than 2.5 inch! if this is all good here...with a t3 .42/.48, you should see good power till redline, without the ass dyno getting worried!

[siregcivic]

yea.. last night i cut off the muffler and replaced it with a piece of pipe so it wouldnt exit right next to the gas tank... it made a big difference power to 7k.. so ima get a new exhaust made when i order a new flange:TU:

[Jcazz]

hey! there ya go for shezzie my nezzie...haha dont get to grezzy! lol.....:TU:

[csaddict]

hey! there ya go for shezzie my nezzie...haha dont get to grezzy! lol.....:TU:
What?

[Jcazz]

What?

ROFL!!

[Jcazz]

just hook me up with sum Rep and will call it even lol.....heheh

[JoelAllenClear]

What?

And yet again... I'm with this guy...

[Hellhatch]

I'd would 2 to 2 1/4 is good for na But boosting ya gotta upgrade to at least 2.5.

[The_Acid_Beaver]

Turbos LOVE as little restriction as possible in the exhuast. A 3" downpipe will change the attitude of the turbo dramatically, and a 3" exhuast would just help the goodness.

[kulo]

does a t3 48. 60. make power till 7200rpm :P

[Jcazz]

yes...

[Slowhatch]

Turbos LOVE as little restriction as possible in the exhuast. A 3" downpipe will change the attitude of the turbo dramatically, and a 3" exhuast would just help the goodness.
correct but unless you like a slow spool time you should go with a smaller downpipe. im at 2 1/4 dp and 2 1/2 exhaust, should be great for spool time, but also kills the high end. you can cure that by shifting earlier than redline.

[The_Acid_Beaver]

Slow spool time? Why do people install larger pipes to lower thier spool time, then? My T25 with a 3" DP and exhuast spools insanely fast. (Granted T25s are pretty small, but It starts building pressure from just over 1500RPM.

[Jcazz]

correct but unless you like a slow spool time you should go with a smaller downpipe. im at 2 1/4 dp and 2 1/2 exhaust, should be great for spool time, but also kills the high end. you can cure that by shifting earlier than redline.

?? :hammer:

[99EJ6T]

Why do people install larger pipes, to lower thier spool time?no, to gain high rpm flow. limiting low end power for big top end power gives you an opening for better traction.

My T25 with a 3" DP and exhuast spools insanely fast. (Granted T25s are pretty small, but It starts building pressure from just over 1500RPM. reason being..... t25 is suited for a 1 - 1.3L motors. in those motors that turbo will start making power at around 2400 rpms. add more cfm and, what do you know, higher turbo shaft rpms. the higher the shaft speed at your motors idle, the sooner you make boost. <- wow this looks like a way to pick a turbo :tool:

edit: sorry i am having a bad day.

[The_Acid_Beaver]

That's what I don't understand about what you are saying. A large downpipe will flow more exhuast than a small downpipe. The larger pipe, in my thinking, should allow the turbo to spin up faster due to less restriction past the turbo.

Don't worry, I had a bad day, too. And, on top of that, the rest of this year is going to suck. ;)

[Jcazz]

That's what I don't understand about what you are saying. A large downpipe will flow more exhuast than a small downpipe. The larger pipe, in my thinking, should allow the turbo to spin up faster due to less restriction past the turbo.

Don't worry, I had a bad day, too. And, on top of that, the rest of this year is going to suck. ;)

:TU: yup same here....bad day as well....lol fucking mail didnt send me my ECU yet and i am getting a little pissed.....hahaha...mail guys = :jesus:

[Slowhatch]

Slow spool time? Why do people install larger pipes to lower thier spool time, then? My T25 with a 3" DP and exhuast spools insanely fast. (Granted T25s are pretty small, but It starts building pressure from just over 1500RPM.
yeah because t25's are about the size of my hand. i hear it all the time from wrx and evo owners that when they put their stock exhaust on, they spool a lot quicker which is better for stop and go traffic. this with their stock turbos, but upped the boost.

[99EJ6T]

That's what I don't understand about what you are saying. A large downpipe will flow more exhuast than a small downpipe. The larger pipe, in my thinking, should allow the turbo to spin up faster due to less restriction past the turbo. only to a point, too large and it will changes the way the gas leaves the turbine (slows down the exhaust gas, due to expansion).

DO NOT CONFUSE THIS WITH BACK PRESSURE! back pressure is the evil that most people try to fight by using a 3 dp/exhaust even though a 2.5 in would do just fine. in other words;

3 dp/exhaust w/ some back pressure < 2.5 dp/exhaust w/o back pressure

get it?

btw: size and flow don't always walk hand in hand. therefore you should only use the largest size required to maximize efficency of the turbo you are using.

[Jcazz]

also another good point Rep for you~ !

[The_Acid_Beaver]

99EJ6T-
THAT makes a lot of sense. Sooooo . . . would it be better to transition to a larger pipe, so you maintain velocity exiting the turbine, but still attain the maximum flow rate of the larger tubing, like the open header exhaust systems you see on cars like Bisi's?

[icarusdown]

...Just for the record, you want LESS timing advance as the RPMs increase. This is because the engine is rotating faster so the time it takes for the combustion event will have to occur later in the compression stroke or the piston will be moving upward into an expanding volume of gas...


wrong.

when the pistons are moving faster you have less time to capitalize on the power stroke, yet the combustion event requires the same amount of time to complete regardless of RPM. This is why you advance spark so that the expanding gases will accelerate the piston on the way down, instead of being late (i.e. retarded) and catching the piston when it is already nearing BDC.

[siregcivic]

hey i got an idea that will take away all my problems... what about a t3 60-1???? too big?? lol bet i would make power to 9k but wouldnt have power till 4k lol..

[99EJ6T]

99EJ6T-
THAT makes a lot of sense. Sooooo :hijacked: . that was a flawless thread jack.would it be better to transition to a larger pipe, so you can maintain velocity exiting the turbineyes, for street cars seeing less then 290 whp. after 300 whp .... well most turbo d's move more air then a 2.5 in. dp (w/ full 3 in. exhaust) can support, so at that point 3 in dp would be best.open header exhaust systems you see on cars like Bisi's?he is not looking for low end punch, just the end high whp number. besides the velocity of air moving from his motor would not require any more backpressure then just the bends in the header to make power.