84 x 89 mm vtec motor, edelbrock im and itr cams b16 head stock ports.
miniram manifold and a t3 60-1 with .63 ar exhaust housing
tial 44mm 10 psi spring and hallman mbc
full 3" turboback no cat
tuned on neptune rtp


for the life of me i cant get rid of this little dip in my graph.
blue line is 12 psi, red line is 17 to 18 psi


before you say anything, there is boost creep, about 1 psi from around 17 to around 18 psi (even with the tial 44mm). either way i cant get the power to not hit a flat spot around 6500. i added over a degree of timing on the dyno and i didnt gain any tq and lost a tiny bit of hp so i took that back out( running between 13 and 15 degrees total in vtec at 18 psi with no signs of det. on the plugs). the afr in that area is low to mid 11s, and i dont wanna go leaner. what could be up?

even when i had my car tuned at evans last year, i still had the same crap going on only the flat spot was around 500 rpms lower



Modified by blackeg at 6:10 AM 4/25/2008

 

Mine did that an it was my vtec crossover point. More info on your setup.

 

You just said it creeps 1psi. What makes you think that's not just the creep?

My charts with creep looked the exact same. The torque curve is on it's way to flattening out or heading south, then the boost creeps and it picks back up again, making what looks like a dip in torque.

 

i had something similar at vtec crossover

 

Hey dumb and dumber, he's not crossing into VTEC at 6,700.

 

Im pretty sure hes talking about the dip at 4,700 RPM, which would be his v-tec crossover..im assuming, but im a noob so.

 

my vtec is at 4700, however thats not my main concern. im talking about how the slope of the graph doesnt keep the same between like 6300 at 7000, then it picks back up. also, the torque looses like 10 or 15 ftlbs in there alsoMy charts with creep looked the exact same. The torque curve is on it's way to flattening out or heading south, then the boost creeps and it picks back up again, making what looks like a dip in torque

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hotredux &raquo;</TD></TR><TR><TD CLASS="quote">You just said it creeps 1psi. What makes you think that's not just the creep?.</TD></TR></TABLE>

the 1 or so psi that im creeping isnt going to cause my car to gain 75hp in a 1000 rpm range

 

just by looking at your graph you have boost creep more than just 1 psi. the dip u r talk n about in the 6300 rpms is mostl likely where boost settles out for a little bit then starts creeping some more.

Also you need to raise your vtec to get rid of the dip at 4700rpms. try increasing it to 4900

 

where are you dumping the wastegate exhaust?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blackeg &raquo;</TD></TR><TR><TD CLASS="quote">the 1 or so psi that im creeping isnt going to cause my car to gain 75hp in a 1000 rpm range

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

First off, it's not picking up anywhere near 75hp from the recovery of that dip. I don't see where you're getting that from. Forget about the HP curve altogether and look at the torque curve because that's what matters and isn't RPM distorted.

It isn't picking up all the much torque (about 15-20ft/lbs) and on an efficient motor like that and a large turbo the amount it's picking up is completely realistic for 1-2psi of creep.

Maybe this will help a little. Notice, it isn't really picking up a massive amount of torque, and I even drew a best guess of where the torque would be headed without the creep.




<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted k20 &raquo;</TD></TR><TR><TD CLASS="quote"> the dip u r talk n about in the 6300 rpms is mostl likely where boost settles out for a little bit then starts creeping some more.</TD></TR></TABLE>

Exactly.

 

thats just how the motor wants to breath. everything seems pretty natural. you would have to change how the motor breaths to get that out. ie intake manifold, cams, headwork etc.

 

i know what you guys are saying about the tq. even though my table timing is about 13 degrees total in that area, the actual timing jumps from 20 to around 23 degrees right at 7k where the power jumps back up.


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 2point2 &raquo;</TD></TR><TR><TD CLASS="quote">where are you dumping the wastegate exhaust?
</TD></TR></TABLE>

dumptube follows the downpipe under the oil pan and ends like right under the halfshaft


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mike@synapse motorsport &raquo;</TD></TR><TR><TD CLASS="quote">thats just how the motor wants to breath. everything seems pretty natural. you would have to change how the motor breaths to get that out. ie intake manifold, cams, headwork etc.</TD></TR></TABLE>

im going to lebanon tomorrow, curious to see what i can get out of it with the current setup

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blackeg &raquo;</TD></TR><TR><TD CLASS="quote"> im going to lebanon tomorrow, curious to see what i can get out of it with the current setup</TD></TR></TABLE>

Haha! Good luck. You're from NY so you probably already know the deal with Lebanon. Expect about a half second and 3-4mph slower than you should go.

 

we had i think close to 23deg at 20psi off that same turbo useing cam2 gas double check your map see if anything looks kinda funky on the timing side

 

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

Haha! Good luck. You're from NY so you probably already know the deal with Lebanon. Expect about a half second and 3-4mph slower than you should go. </TD></TR></TABLE>


haha yeah ive been going there for years. i just want seat time and practice launching and ****.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Day-DayC &raquo;</TD></TR><TR><TD CLASS="quote">we had i think close to 23deg at 20psi off that same turbo useing cam2 gas double check your map see if anything looks kinda funky on the timing side</TD></TR></TABLE>

im using pump gas, 93 octane. my timing looks consistant, and i tuned for mbc on the dyno when i kept adding and didnt see tq gains i pulled a lil bit back

 

It may be manifold design that is permitting the dip and also backpressure on the exhaust side.

With that displacement you should be using a larger turbine A/R and that will most likely cure your problem.

 

show us torqe graphs

 

the torque is on the graphs, its the lower lines around 250-300.


i took the car to the track yesterday and based off the datalogs it was seeing 15.5 psi around 5500rpms and got up to 16.9 near redline

 

oh yea, ive got the less still spring in the boost controller now. i might throw in the stiffer one to see if it can keep the boost level steadier.

i guess i can also say im dissapointed in still having a little creep, since i just spent like 400 bucks on a tial 44 to solve the problem

 

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

Look above.... they are there.

 

It's not WG size, but manifold design that is the creep problem....

 

yea, im pretty sure thats the reason, oh well. no money for new mani this year so i guess ill just be creepin and creepin lol

heres the best pic i currently have of it




Modified by blackeg at 7:49 PM 4/27/2008