I have come accross a some what mind boggling scenario.

Just turbo charged my pretty much b18 stock block,

Im not sure how much depth i need to go into,

but i seems to be building boost (gauge showing) and have tried few a couple of gauges, however my car is extremly slow.

Ive got a SC61 Turbo with inline pro log manifold, external waste gate...750 RCs.. etc..

Running Hondata s300

Id guess im running around 150-160 WHP, and im running about 10psi of boost, the car seems to be struggling... id imagine looking at post on here i should easily be running around 210-230WHP with my setup...

i just cant seem to work it out... except the turbo may be knackred but there is no play and it seems a relativly new turbo with minmal milage

I would like to mention i had given my head in for some work, 3 angle vlave job and cclean etc but nothing major dont see how tht could affect anything .. could be wrong!


Any advice is more then welcome i am completly out of ideas especially after spending so much $$$

Thanks in ADVANCE!

 

valve leaks? boost leaks?

what have you eliminated as an issue?

 

I've tuned several cars with this symptom and its generally either a boost leak or a bad wastegate/spring.

Most recent happened last week, the guys wastegate spring was mangled. Management showed full boost, but it built boost slower and just didn't pull that hard....tossed in a new spring and she was bakin tire.

 

What are your A/F ratios while it is doing this? Like stated above ^^ check for boost/vacuum leaks and check out the wastegate. Try pressurizing the charge pipe system with the motor not running using an external system (bike pump etc.) How is the car acting exactly when you drive it? Stumbling the whole time you drive it? certain RPM? Has the car been tuned?

 

is the S300 actually tuned? i didnt see that mentioned above.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dpetro1 &raquo;</TD></TR><TR><TD CLASS="quote">is the S300 actually tuned? i didnt see that mentioned above.</TD></TR></TABLE>

That was my first thought. For some reason, this is an issue more often than it should be...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Schister66 &raquo;</TD></TR><TR><TD CLASS="quote">

That was my first thought. For some reason, this is an issue more often than it should be...</TD></TR></TABLE>

agreed. estimated whp leads me to believe that it isnt tuned but maybe we are lucky and he got a street tune. either way we will give him a break since he's rom the UK

 

Do you have plans to build the bottom end?? For your goals of 220-230whp, the SC61 is about the furthest thing from a "good choice" that i can think of...That turbo is way too big for a stock block application. You're going to have a lot more lag than necessary and still make the same power as someone with a smaller 57 trim or similar turbo

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dpetro1 &raquo;</TD></TR><TR><TD CLASS="quote"> either way we will give him a break since he's rom the UK</TD></TR></TABLE>

Lol...i dont know why that makes any difference, but it made me laugh regardless

 

opps, didnt mean to sound offensive. just seems like there arent a ton of tuners over there so maybe thats why he was unsure how to go about getting a tune

 

Thanks for the replies ppl!

Right the car has had a street tune, and it runs good a/fs 12s mainly on s300

The waste gate im using is turbosmart, its brandnew... ive change the spring also to a bigger one but the same issue occurs.

I had a tuner look at it, i dont believe there to be any valve leaks, or boost leaks acccording to him, however the guy i took it too is abit of a lazy **** and could just be fobbing me off :S
but then thers no real reason why he woulndt do it.

Is there any easy way to check for boost or valve leaks?

When im driving the car is deffiantly hesistating, but there are very slight moments when it just feels like going.

Not sure if its worth mentioning but the dumpvalve goes off just fine.

Is there any distinct possibility it maybe the turbo?

 

you've got a massive boost leak somewhere.

plug in a boost gauge to the compressor outlet and then one to the manifold and check the differences.

Take a spray bottle with soapy water and spray all your connections, and check for bubbles. Spray down the intercooler too.

 

a friends car had some issues before it built boost but no power. turned out to be a clipped turbine wheel

 

I have always looked for a boost leak but never have been able to find one, however i will try this at some point, just to elminate few more things.

Any more experiances people have had please? just so i can do everything as much as i can without trailing my car everywhere.


Also just a generic question, can boost leak cause a turbocharger to go stop working properly in the long run (long run i mean 500-1K miles)

 

Also to add, if i take my turbo charger off and it is naft, as it has some play now, could a turbo specialist distinguish the reason why it has stoped working propery ? or what ever has caused its damage?

I would just like to mention that my car holds the boost absaloutly fine!!


Modified by mikkey1 at 7:28 AM 5/8/2008

 

bump for more info please!!!!

 

If it makes boost and holds it fine, i would suspect the tune is the issue. You may be running super rich in boost or something. I would visit the tuner and see what's up...

 

http://www.supramania.com/foru...19718

Make one of these and come back with what you find.

 

Do u have a dump tube on the wastegate that directs the exhaust gases under the oil pan?

 

Sounds like the timing is retarded too much. Here are the signs: 1) Engine is running very cool 2) exhaust is very hot, maybe even glowing. 3) turbo spools real quick, but the motor is not on the pipe at all

Your ignition timing might be right in the tune, but your cam gears might be off a tooth on the belt, or skipped a tooth. Check to make sure that all the gears line up right with the crank, or crank trigger.

 

i have the same issue. i changed the motor and used the same turbo and i still have the same issue. ive had 5 different tuners tune my car and they all havent been able to figure out what it is. my next step is to change out the turbo.

 

i took my turbo to a place here in miami fl called mic turbo and they looked to see if the shaft had any play. they looked for bent fins. they asked if it smoked and then they told me it was perfectly fine since it doesnt smoke,have shaft play, or have bent/broken fins.

 

i had this problem with a t3/t04e at 12+psi, turned out my tiny intercooler could not cool the intake charge and my iat was 160+ degrees, car didnt start to move until 18psi, switched to a larger intercooler and at 14psi the car felt faster than it did at 18 with the smaller intercooler.

 

I will go ahead and make a boost leak tester and go from there.

Yes i do have a dump tube made going under the oil pan.

My intercooler of avaerage size dontthink that will be effecting anything, thanks for the replies!

Any more experinces ppl have had are welcome!!!

 

hi mate, im from manchester in uk, you close?

anyway, it doesnt sound like a boost leak to me, yes a boost leak would cost power, but not much unless it was hugeeee, because if you did have a boost leak, basically the turbo would just spin harder to make up the lost boost, as the wastegate opens dependant upon pressure in the boost circuit, if you had a leak there would be less pressure in the circuit, thus the wastegate would not open, so by having a leak it just means the turbo will need to work harder to maker enough pressure to get to the point of wastegate opening, but you will still have the pressure! it might be a tad warmer charge due to overspooling a little, but its not going to cost you that much power.

noone has asked about your exhaust, what are you running? standard? as a small bore/restrictive exhaust will really hold the car back now, i would try removing the exhaust and running downpipe only just to eliminate it (dont wanna go buying a full new exhaust for nothing).

and finally as someone already said, ignition timing retarded to far. have you had the car mapped on rollers, or is it just a universal map your running? timing makes a huge differance to power!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mikkey1 &raquo;</TD></TR><TR><TD CLASS="quote">My intercooler of avaerage size dontthink that will be effecting anything, thanks for the replies!</TD></TR></TABLE>

mine was average size too, i thought it would be good enough but the IAT told a different story, are you able to measure your IAT?