Markb16a

I have a question for you guys ever since I got my car tuned and rollin I have noticed that When I am at full boost which is at 10 psi right now DD and rev it out and go in the next gear it falls back to 5 psi and go back up to 10 psi isnt supposed to be like hit 10 psi and go in the other gear and hit 10 psi again right away? Or is it supposed to fall off and go back up to full boost again?
thanks
Sohc Turbo
JDM D15B stock block
t3/t4 57 trim .63a/r
rc 550cc injectors
7lb tial wastegate
2.25 exhaust w/ 2.5 dp

Throwdown

iTrader: (2)

it could be a few things.... but what tranny are you running? and can you post a dyno chart?

Luserkid

Turbo boost will always fall out of pressure once your foots off the gas. Also depending on the boost controller that will need to pick up to work the wastegate again. Theres alot to it but if your on a journal bearing (which you are) you wont get back to boost like you think. I believe Ball bearing do but dont quote me on it.

Throwdown

iTrader: (2)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Luserkid &raquo;</TD></TR><TR><TD CLASS="quote">Turbo boost will always fall out of pressure once your foots off the gas. Also depending on the boost controller that will need to pick up to work the wastegate again. Theres alot to it but if your on a journal bearing (which you are) you wont get back to boost like you think. I believe Ball bearing do but dont quote me on it. </TD></TR></TABLE>

ke98248

iTrader: (1)

You're on a journal bearing along with the fact that you're running a huge-*** turbo, so it takes about to 5.1K to hit full boost... I should know, I have the same turbo as you. Throw in a test pipe and you'll notice a bit of difference, enough to warrant loosing the stock-cat, unless you have emissions

Schister66

What you're explaining is called the "transient response" or recovery time of the turbo. When you shift, the rpms drop off as does the engine load. The amount of exhaust energy to the turbine drops significantly and therefore turbine speed falls. When you get into the next gear and back on the throttle, the exhaust energy must respool the turbine; therefore, creating boost once more. Certain turbos or CHRA combos can combat the problem of slow transient response, but as with everything else, it comes with a price.

At 7psi, your 57 trim is not going to be spooling very fast and will have slow(er) transient response on your D series. If you want to have a more responsive setup, sell the 57 trim and get something smaller like a 50 trim or T3 Super 60. If you need/want more answers, check out the Forced Induction Forum.

93whtlx

I know its not a honda its a ford. Beat me up now. honda is functinal and ford is FUN. Boost carried over between gears, My opinion. It is good to a point but to much carried over to the next gear causes blown tranny. I gotta fork over 1g for a tranny and all the fixins. You should drop 2-3lbs between gears, depending on your shifts. That is my opinion with boost.

Schister66

^^Thanks for the "answer" that didn't really answer anything

For a Honda, a Vortec supercharger is the worst form of FI

93whtlx

I'm still learing of hondas to. I just ordered a b16a swap for mine and I am gonna turbo it so I will check on your post and topics to find out info on what to expect. Wish I could be of some help.

95dxsir2

instrument

is there a reason you posted a picture of your stock sohc in this thread? seriously?

op,that's a big turbo on your li'l sohc, must be funn

93whtlx

I'm still learing of hondas to. I just ordered a b16a swap for mine and I am gonna turbo it <U></U>so I will check on your post and topics to find out info on what to expect. Wish I could be of some help.

Before getting smart next time. Look and read.

steerh67

you and about a thousand other people on here are "going to turbo". The reason for the response was that all you did was take a picture of the underside of your hood. Everybody knows what the engine compartment of a civic looks like, so posting it was a moot point. Also, this is a technical thread started by somebody else, you didn't answer his question, you just posted pictures irrelevant to the topic of discussion

Schister66

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by instrument &raquo;</TD></TR><TR><TD CLASS="quote">op,that's a big turbo on your li'l sohc, must be funn</TD></TR></TABLE>

I would think quite the opposite. The turbo must spool rather late and apparently doesn't recover very fast. A properly sized turbo would be better for the street

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by steerh67 &raquo;</TD></TR><TR><TD CLASS="quote">you and about a thousand other people on here are "going to turbo". The reason for the response was that all you did was take a picture of the underside of your hood. Everybody knows what the engine compartment of a civic looks like, so posting it was a moot point. Also, this is a technical thread started by somebody else, you didn't answer his question, you just posted pictures irrelevant to the topic of discussion</TD></TR></TABLE>

Lol...i've heard "i'm going to turbo" more times than anyone ever should. After a while, you learn to ignore it

ke98248

iTrader: (1)

Agreed, partially. If it was a ball-bearing turbo, the "lag" created would be minimized slightly -- whereas with a smaller trim, it would be quite a difference.. But, I don't think that purchasing this large of a turbo was really much of a bad thing, if I want boost, I just mash the throttle or down shift, easy as that. SovietXDay has a 280WHP d16z6 on the same turbo as me, and he loves it.

Plus, it gives me good MPG, when I want boost I just hit the throttle and I'm there, whereas if I need to get around town or cruise the highway, I pretty much stay outta boost.

Markb16a

well right now I am currently running 2.25 exhaust and no cat here but yes it kinda spools late for a .63 a/r exhaust housing but its all good What i was trying to find out was if that was normal for it to be like that or should it be like full boost when you rev out when switching gears hopefully 3 inch exhaust would be beter for it to spool up faster also I ziptied every vacuum line down good but the ones I couldnt get I left them alone but it fell back to 8 psi this time not originally at 5 psi so that helped a lil as well.

TheShodan

iTrader: (14)

Opening up your exhaust will assist in your quest for more transient response because the exhaust gasses can escape much more effectively since the amount of backpressure will be lessened.

And as for the ball-bearing CHRA spooling "faster", it depends upon the right combination with the motor. "quick spool" (I hate that term) from a ball-bearing CHRA is a by-product of the wheel design in conjunction with the CHRA, not the CHRA itself. This is why the "converted" T series (57, 60, 50 trims etc) did not do so well, because it didn't really change the characteristics of the turbocharger as buyers expected. But this is all discussed in the FI forum.

Schister66

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TheShodan &raquo;</TD></TR><TR><TD CLASS="quote">And as for the ball-bearing CHRA spooling "faster", it depends upon the right combination with the motor. "quick spool" (I hate that term) from a ball-bearing CHRA is a by-product of the wheel design in conjunction with the CHRA, not the CHRA itself. This is why the "converted" T series (57, 60, 50 trims etc) did not do so well, because it didn't really change the characteristics of the turbocharger as buyers expected. But this is all discussed in the FI forum.</TD></TR></TABLE>

QFT although as always, this advice will fall upon deaf ears

gettin it

Told ya bro. Swap out your manifold, and get a good boost controller if thats what you want. Or you can get a different turbo. Many things you can do. but the boost controller would be your best bet. Like i told you on mine, i can set my turbo to start boosting at a certain rpm and make it hold that pressure also. If you want to get one, my homie might be selling his. But you can still upgrade your exhaust and change your turbo manifold.
Latz your neighbor.

thaboosh

Turbos run off of exhaust pressure obviously, so when you switch to the next gear, it takes a bit to fully spool.
My 1.8t gti drops about 10psi between shifts unless im loosing traction in 3rd.
But yea. Im running 21 psi and usually see 7-10 psi drop between shifts. On ballbearing turbo. Not journal bearing. It will take longer for journal bearing.
And make sure that on the oil feed line to the turbo that the oil restrictor is taken out because if not, it will wear out the jiurnal bearings.

spotscivic

if you dont want to lose boost pressure between gears take off your BOV....joking. so your probly just gonna hav to learn how to shift faster. or get a quicker setup for shifting. but even then your gonna lose boost. smaller turbo maybe.

Tuner Eddy

you're running a big turbo on a single cam, of course your gonna lose boost when shifting...

hades

OP: If you're unconcerned with turbo life, or want to do two tunes on the ECU (I.e., put in a ground switch that'll switch between programs for the track and street/DD duties - Moates has these available) you can keep even a plain bearing turbo spooled a little bit with a rally-type tune where you go rich and retard timing a boatload during closed throttle events. This'll cause still burning mixture to dump into the turbo/manifold and create a bit more pressure there so the turbo stays more spooled.

However - IT WILL KILL YOUR TURBO AND QUICK - it tends to put a tad more heat into the turbo, thus the requirement that you don't mind getting new turbos often, or you don't mind running two programs...

I'll go get my flame suit because everyone's gonna tell me that I'm a dumbass and that you shouldn't do it... I'm just throwing the option out there...

OMGWTFBBQ!

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by spotscivic &raquo;</TD></TR><TR><TD CLASS="quote">if you dont want to lose boost pressure between gears take off your BOV....joking. so your probly just gonna hav to learn how to shift faster. or get a quicker setup for shifting. but even then your gonna lose boost. smaller turbo maybe.</TD></TR></TABLE>


All the cool kids have compressor surge

Markb16a

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


All the cool kids have compressor surge </TD></TR></TABLE>
what exactly is compressor surge?