So I hit the dyno today and made some runs to compare the JUN ecu and a chipped P13. Attached are the graphs:

RUN 39 is chipped P13


RUN 65 is the Jun ECU.


Here's my setup:

Iceman w/ HKS SMF
Skunk 2 IM
Jun camshafts
Jun valvesprings
Portflow retainers
Skunk 2 cam gears
Mugen Header
Test pipe
Tanabe Ultra Medalion
UR pulleys
Spoon 70mm TB
Quaife LSD
JUN flywheel
Exedy organic clutch
VAFC (untuned)
Stock head
Stock bottom end

Wheel:
18 x 7.5 Work Emotion (17lbs)

Tire:
225/35/18 Falken FK451 (22lbs)

Brake:
AEM big brake kit w/ Spoon caliper

Both runs produced similar WHP, but Torque is greater with the JUN ecu.
However, both of my max power tops out at ONLY 7000 rpm, most of the dynos Ive seen with Jun cams makes power all the way to 8000. Whats seems to be the problem here? I cant seem to maximize the potential of these cams.
Before the Jun cams I was running with TypeS cams and got 185 whp, I ONLY gained 7 whp by switching to JUN valvetrain, thats way too low than expected?
It seem like there's some restrictions from 7000 onwards, could it be my exhaust? I notice most ppl with Jun cams have 2.5 inches exhaust, but Im still using 60mm catback. Would that make a big differences?

Modified by VSBB6 at 9:25 PM 2/26/2005


Modified by VSBB6 at 11:36 PM 2/26/2005

 

try hondata

 

Im switching to AEM EMS in next few weeks, hopefully will get more decent numbers and able to extract the power missing from 7000rpm onwards.
Do you think its beneficial to get a FPR and bigger injectors?

 

You'll be fine with the stock injectors up to like 220whp, no worries there. Get hondata or the aem ems and go to a GOOD tuner. TUNING IS EVERYTHING. You should be making like 210-215. When I had intake, header, exhaust, intake manifold, light flywheel, and hondata s200 on an otherwise stock jdm h22a, I put down 191whp and 148tq with just about an hour of tuning (conservatively). At the time I just wanted it to run well until I could finish my build. You are missing out on a lot of power there so get that ems and spend some quality time with some rollers!

 

I'd switch to a 2.5" exhaust, including the cat (if you have one) downstream of that header.

edit: also, if you're spending time on the dyno, why is your VAFC untuned?

 

I'm not 100% sure the stock injectors can provide enough fuel to make good power over 7500 RPM. The max pulse width is very short when the engine is moving that fast. He might need to go to bigger injectors and or higher fuel pressure, to get enough fuel delivery during this short time.

You will need ALOT of time spent on the dyno tuning it in with a wide band O2 to know for sure. But from looking at your plots I bet your not getting enough fuel at 7500+ rmps.

 

I couldn't get A/F reading today because the shop's wideband broke down, so it didn't allow me to do any tuning. Those are back to back baseline runs with 2 difference ecu's.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Greyout &raquo;</TD></TR><TR><TD CLASS="quote">I'd switch to a 2.5" exhaust, including the cat (if you have one) downstream of that header.

edit: also, if you're spending time on the dyno, why is your VAFC untuned?</TD></TR></TABLE>

 

That could be a possiblity, what size/brand of injectors do you recommend for my setup?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 577HondaPrelude &raquo;</TD></TR><TR><TD CLASS="quote">I'm not 100% sure the stock injectors can provide enough fuel to make good power over 7500 RPM. The max pulse width is very short when the engine is moving that fast. He might need to go to bigger injectors and or higher fuel pressure, to get enough fuel delivery during this short time.

You will need ALOT of time spent on the dyno tuning it in with a wide band O2 to know for sure. But from looking at your plots I bet your not getting enough fuel at 7500+ rmps.</TD></TR></TABLE>

 

Hold off purchasing injectors until you can verify what is going on with a wideband. In fact, the best investment you could make right now would be a wideband setup for the car.

 

I already have AEM UEGO in the car.
Some ppl says its my cat back exhaust is too restrictive for the Jun cams, switchting 2.5 or 3 inch would free up the hp at the top.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by VSBB6 &raquo;</TD></TR><TR><TD CLASS="quote">I couldn't get A/F reading today because the shop's wideband broke down</TD></TR></TABLE>
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by VSBB6 &raquo;</TD></TR><TR><TD CLASS="quote">I already have AEM UEGO in the car.</TD></TR></TABLE>
ROFL, if you have a wideband you wouldn't have needed the shop's when you had it on the dyno. So how did the a/f look when you did each of those runs?

 

a 3in. exhaust is too much for your setup. The size of an apex'i n1 will be fine which is 2.36 or a 2.5 inch will be plenty. If you have the 2.36, the 2.5 really won't help you much.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by VSBB6 &raquo;</TD></TR><TR><TD CLASS="quote">VAFC (untuned)
</TD></TR></TABLE>

Why?

 

thats really nice numbers without tuning and stock head besides the obvious. I'm hoping to be around that when i get mine tuned.

 

whats your CR? stock 10.0?

 

he said stock bottom end so im guessing yes

 

always a chance he swapped for the jdm h22.

but isnt the setup lacking higher compression? he forgot about that when he was trying to maximize the potential of his cams

 

well with those cams, yeah i can see why the CR needs to be boosted. Also he needs a higher rev limit so he can get the rest of the cam.

 

Three things are probably hurting you .......

1) Stock compression. Anything that big with that much duration needs higher compression. If you think about it, the Type S cams are in an engine that has 11:1, and the Jun's like around 12:1, so gaining 7 whp by just changing cams, and doing nothing else isn't bad. Especially with cams that like higher compression.

2) Exhaust flow. 2.5" all the way back, no doubt about it. You're not doing the cams any justice with anything less.

3) Tuning! Like everyone said, you need a wide band O2 to tune it. Usually when you go over the stock rev limiter, the map just runs an interpolated number for the fuel added, so it is definitely not tuned for the exact set-up you have. "Chipped" ECUs are all fine and dandy if you are running the EXACT set-up that the programmer used to design the chip for, but even then there can be variations for each car.

Get that compression up some how. You're running 8,700 with a stock bottom end with just springs and retainers?? Is it just me, or is that really brave?? I thought that you shouldn;t go much uver 8 without sleeving the block on an H22? But then again, what the hell do I know .........

 

The A/F was fluctuating between 12.1 to 14, i know hat you mean but its more accurate to tune with a graph output.

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

ROFL, if you have a wideband you wouldn't have needed the shop's when you had it on the dyno. So how did the a/f look when you did each of those runs?</TD></TR></TABLE>


Modified by VSBB6 at 7:49 AM 2/28/2005

 

Problems with most cat-back exhaust is the 2 inch center pipe which connects to the stock cat creating a bottle neck. A 2.5 inch cat-back all the way with less restriction should free up some power at the very top.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jd3jdm &raquo;</TD></TR><TR><TD CLASS="quote">a 3in. exhaust is too much for your setup. The size of an apex'i n1 will be fine which is 2.36 or a 2.5 inch will be plenty. If you have the 2.36, the 2.5 really won't help you much.</TD></TR></TABLE>

 

I have that in mind, but I have seen Jun cams on stock compression hitting over 200 whp at 8000 rpm. Think it was tuned with AEM EMS though...

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Daboi630 &raquo;</TD></TR><TR><TD CLASS="quote">always a chance he swapped for the jdm h22.

but isnt the setup lacking higher compression? he forgot about that when he was trying to maximize the potential of his cams

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

 

i took my car to the end of my 5th gen tach when i had my jun head.

When switching to the JUN valvetrain, only reving to 7 isnt going to net you a damn thing. You gotta take it all the way to TRUE 8K + You need a better tuning program as suggested by everyone thus far.

for 1K bucks, i dunno if id go for the EMS. for 300 and the ecu of your choice (P28,P72) and conversion harness if its a 5th gen you could have hondata plus the extra cash to get her tuned at say... church

 

yeah i am in dire need of an OBD-1 ecu.....but i guess OBD-2 can work for now.

 

I am running JUN ecu and took it up to 8500rpm on the dyno, but power falls off after 7000. It is most likely due to the tunning.


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98TypeSH &raquo;</TD></TR><TR><TD CLASS="quote">i took my car to the end of my 5th gen tach when i had my jun head.

When switching to the JUN valvetrain, only reving to 7 isnt going to net you a damn thing. You gotta take it all the way to TRUE 8K + You need a better tuning program as suggested by everyone thus far.

for 1K bucks, i dunno if id go for the EMS. for 300 and the ecu of your choice (P28,P72) and conversion harness if its a 5th gen you could have hondata plus the extra cash to get her tuned at say... church </TD></TR></TABLE>