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**DONOTDELETE**
12-16-2002, 01:26 PM
Rosen Autosport here in Richmond, VA recently finished working on my all motor engine and installed it. But the dyno results are much lower than I expected:

155 RWHP, 148 TQ on 93 octane pump gas

... and this is with the following:

1996 KA24DE (head port & polish), 0.040 overbore, 10:5 compression w/ JE pistons, JWT ECU, JWT Camshafts, UR underdrive pully, Hotshot Headers, Injen CAI Intake, AIV/EGR block off kit.

doesn't this seem low? should investigate a problem somewhere that's causing such low numbers?

Dave


__________________
91 S13 with:
1996 KA24DE, 0.040 overbore, 10:5 compression w/ JE pistons, JWT ECU, JWT Camshafts, UR underdrive pully, Hotshot Headers, Injen CAI Intake, Whiteline Swaybars, KYB AGX shocks, Eibach Prokit Springs, Porterfield R4-S brake pads, cross-drilled front rotors, AIV/EGR block off kit. Soon to add Rota Subzero 16x7 Silver wheels with Sumitomo HTR Z II tires...

Greaser_
12-16-2002, 01:44 PM
get colder plugs and retard your timing 5 degrees see how that pulls on the dyno.

also as a drastic measure, put a stock head on. might of hurt more than helped.

get rid of the cold air extension on the dyno once, a reliable source said the pipe in that section is a big restriction.

ADAM HUTCHINSON
12-16-2002, 01:49 PM
hmmm...that does seem low...is the motor broken in yet?

uiuc240
12-16-2002, 02:29 PM
did you use a wideband O2 sensor during the pull? could have excessively rich fuel readings causing low numbers due to inherently-rich JWT ECU. maybe time for S-AFC to lean things out? Do you have the printout?

Eric

Hugh
12-16-2002, 03:11 PM
What gas are you running on? Timing and fuel is a big part.

Any backpressure in the exhaust? You'll probably pick up torque with a little back pressure.

**DONOTDELETE**
12-16-2002, 03:43 PM
It had 93 octane pump gas and I haven't personally checked the timing yet...but hopefully they know enough to set it correctly at 20 btdc...

the engine is at 600 miles now with new mobil one 5W-30 oil..

Dave

**DONOTDELETE**
12-16-2002, 03:43 PM
Greaser - is there a good shop with dyno down in VA beach area?

Greaser_
12-16-2002, 04:16 PM
yeah, Abacus racing in Norfolk. all the peeps in Va beach go there.

i wouldnt trust rosen "to know" so just check. If you dont know how to do those things i suggested let me know so maybe more explanation is needed.

allmotorKA
12-16-2002, 04:18 PM
I thought that Mobil 1 synthetic oil was not recommended for breaking in an engine...heard that it doesn't allow the piston rings to seat properly. Have you done a compression test yet?

Greaser_
12-16-2002, 04:20 PM
Its not good for breakin in. but it reads "new mobile yada yada" indicating that he just put the stuff in.

White_240sx
12-16-2002, 05:20 PM
</font><blockquote><font class="small[/img]In reply to:</font><hr />
You'll probably pick up torque with a little back pressure.

[/QUOTE]

Backpressure decreases torque.

Your dyno doesn't seem too awfully low for a motor that uses off the shelf parts that aren't designed to work with each other. Your bottleneck is probably your intake system. If you have the budget, try running a set of ITB's with a surge tank to feed them so you can keep your MAF and have the ECU adjusted for the change. You can always have the stock intake manifold ported before you dump money on ITBs or a custom intake manifold if you donít really want to spend that kind of money in the motor. Also, who did your headwork?

sillbeer
12-16-2002, 05:59 PM
I was always under the impression that back pressure created torque. http://forums.freshalloy.com/ubbthreads/images/icons/smirk.gif

asad
12-16-2002, 06:08 PM
</font><blockquote><font class="small[/img]In reply to:</font><hr />
I was always under the impression that back pressure created torque.

[/QUOTE]

No, good flow velocity leading to increased scavenging creates torque. This generally requires smaller piping, which necessarily have higher backpressure. Backpressure is an effect, not a cause.

Asad

RDM_II
12-16-2002, 06:34 PM
Ouch mang, I put down 159.8 on mine, running only bolt-ons and OE exhaust. You need some serious fine tuning at least.

thoraxe
12-16-2002, 07:10 PM
are you running stock exhaust??

I would say check timing, check mixture. Are the cams dialed in right? You should check the cam timing, that can be the source of a lot of your problems. Does the JWT ECU know you've got 10:1 and the JWT cams, or is it just a "shelf" JWT?

S13Sean
12-16-2002, 08:02 PM
I'm new to the Nissan thing and don't know how well the 240sx head flows. In my 16V I had some work done but most of the attention was paid to the bowls and valve guide area. The shop didn't lower the ports either which is a big no-no apparently. What exactly was done to the head. Also was the head decked?
If so the cam timing will be out and you will need adjustable cam gears to correct this. I am having the same problem with my 16V as the head was decked 0.30"
My Race Car (http://www.evilgti.com)

There is obviously a bottle-neck somewhere and the post about the ITBs. If you have high compression and a good set of bumpsticks you should have good power assuming the head was done properly and not hogged out.

I am curious about how well the head and intake manifold flow because I am debating whether or not to have them worked over.

Even if the fuel was still fat you'd think that the power output from those mods would be a bit better. I guess a stock KA makes about 125hp or so to the wheels?

jam149
12-17-2002, 08:18 AM
That is definitly low. My car with Apexi N1 dual, JWT cams/ecu, and custom 3" intake put down 161RWHP on the Abacus dyno.

my dyno chart (http://www.negative-camber.org/jam149/240dyno.html)

And I'm running a good bit of backpressure with the stock close-coupled cat and stock exhaust manifold. You've got a lot more done to the car. I'd expect in the 180 RWHP area, based on the mods I've done, and what else you've added.

SCC tested a stock car and it put down about 125HP to the wheels. I should really scan that and put it up as a stock comparison.

joe

orion
12-17-2002, 09:45 AM
I have all the SCC dyno charts scanned and uploaded on my site on the 'Dyno Charts' page:
http://www.intmo.com/briand/dyno%20charts.htm

Here's the one you referred to:

http://www.intmo.com/briand/dyno%20charts_files/240sx%20dyno%20chart.jpg

Later - Brian

benevolent
12-17-2002, 12:44 PM
i don't have my charts handy but my KA in my 96 did 145hp,148tq. that was with a GReddy PE catback with ghetto crushbent resonator removal mod, and regular injen intake.

jam149
12-17-2002, 01:05 PM
</font><blockquote><font class="small[/img]In reply to:</font><hr />
I have all the SCC dyno charts scanned and uploaded on my site on the 'Dyno Charts' page

[/QUOTE]

Cool!! You mind if I steal that for my site, as a comparison?

Thanks!

chris4130
12-17-2002, 01:43 PM
First of all, ROSEN AUTOSPORT in Richmond, VA is the worst shop you could take ANY car to. They couldn't put a car togeather *right* if their life depended on it. Yes I have personal experience with them on more than one occasion. Ask them about 300zx n/a - tt swaps if you don't believe me. Anyways I would avoid taking my car back to them, i have herd several other stories along the same lines as the one i'm describing. Good luck on your car, sorry Rosens got their dirty little hands on it.
-Chris

**DONOTDELETE**
12-17-2002, 01:46 PM
Joe: Your dyno chart only shows ~149 RWHP, not 161? Do you have the 161 dyno chart?

Everyone else: I know that Ballos here in Richmond did my head work, but I don't know the lingo ask them what specifically they did to the head...and I've had tension with Rosen, having to take my car back 3 times now for various problems. The main one so far was a bolt on the timing chain stripped out and they had it back in the shop 2 weeks while the took the head out again and heli-coiled the bolt-hole...

If someone else has a dyno chart with similar mods to their engine, or less mods done and higher numbers, I'd like to see it - that would at least be a start of proof - to say that something they missed is causing a big power loss somewhere...

btw, JWT specifically reprogrammed the ECU (2nd time) for 10.5:1 compression and their cams, so it shouldn't be that...

Dave

chris4130
12-17-2002, 01:49 PM
huguetguy- What color/year is your car? Just curious....
-Chris

jam149
12-17-2002, 01:57 PM
</font><blockquote><font class="small[/img]In reply to:</font><hr />
Joe: Your dyno chart only shows ~149 RWHP, not 161? Do you have the 161 dyno chart?


[/QUOTE]


Just scroll down on the page. There's 2 dyno charts on the same web page - the one before the JWT ECU, and the one after the JWT ECU.

Let me know if you still have problems accessing it.

joe

**DONOTDELETE**
12-17-2002, 02:31 PM
mine's a 91, aztec red, with some VT stickers on it...

chris4130
12-17-2002, 02:41 PM
hmmm.. Don't think I've seen you around. I'm in lynchburg during the week so I don't see a whole lot of people I'm home on the weekends though. Consider yourself lucky about them having your car only 2 weeks. My best friend got them to do his 300zx na -&gt; tt swap. It took 8 months and they completely destroyed the car. (No it wasn't running when it left) Anyway stay away from them at all costs. Maybe I'll see you around sometime. If you need a shop that has a good dyno and does Very Good machine/motor work there's a place up here in Lynchburg that does excellent work. Pm me if you want more info (btw lynchburg is a little closer than va. beach) Goodluck,
http://forums.freshalloy.com/ubbthreads/images/icons/grin.gif
-Chris

Mav1178
12-17-2002, 03:25 PM
</font><blockquote><font class="small[/img]In reply to:</font><hr />

155 RWHP, 148 TQ on 93 octane pump gas

... and this is with the following:

1996 KA24DE (head port &amp; polish), 0.040 overbore, 10:5 compression w/ JE pistons, JWT ECU, JWT Camshafts, UR underdrive pully, Hotshot Headers, Injen CAI Intake, AIV/EGR block off kit.


[/QUOTE]

http://www.worldwidechang.com/Pics/Cars/MyCar/Dyno/ECUIntExhPulCamHeadManiHdr2.jpg

JWT ECU, JWT cams, DPR head, Extrune Honed intake manifold, Hotshot header, 5Zigen exhaust, AEM intake, UR pulley.

I actually think your setup is okay with the amount of power it dynoed, but it needs tuning some more.

-alex

Hugh
12-17-2002, 03:30 PM
</font><blockquote><font class="small[/img]In reply to:</font><hr />
No, good flow velocity leading to increased scavenging creates torque. This generally requires smaller piping, which necessarily have higher backpressure. Backpressure is an effect, not a cause.

Asad


[/QUOTE]

SORRY, what I should've said is "Did you put a fatass wide open exhaust on the car or run no muffler at all??"

Many people end up with turbo exhausts on NA cars and go slower.

**DONOTDELETE**
12-17-2002, 04:23 PM
alex - based on your dyno results, with mine having the bump in compression and 0.040 overbore, how much extra would you think that would increase the power?

Dave

Greaser_
12-17-2002, 04:38 PM
did you try any of the things i suggested yet?

**DONOTDELETE**
12-17-2002, 07:25 PM
greaser: I haven't done your suggestions yet, but I was just out there with a vacuum guage and it's vibrating a lot at idle at around 17 in hg. my guage suggests that means late ignition timing...my dad has a timing light, and I'll check the timing as soon as I can...

I want to assume that there's just some component not working or they didn't do crap to tune the engine and try to eliminate all those possibilities before tearing apart the engine and trying a stock head which I don't have...

if they put the cams back on one tooth off, wouldn't that be immediately noticeable...or if they did the timing chains slightly off, that would be a majorly obvious thing, wouldn't it? like valves hitting the pistons all the time, terrible noises, etc?

I hate living in a condo and this being my only car - I might take some days off this christmas and just spend some days ferreting through all the breathing components and trying different things...

Dave

mbmbmb23
12-17-2002, 07:37 PM
I thought JWT wouldnt touch 96+ ECU's because of the emissions stuff (OBDII or something?). If you still have your stock exhaust...I would put that back on there and do a dyno run.

-m

Greaser_
12-17-2002, 07:48 PM
nope, you're idling like that cuz you have cams. thats normal. mine idles at 15 (something or another).

check timing and report back.....i have several tricks for you to try.

jam149
12-18-2002, 11:16 AM
JWT won't do 97 and 98 ECU's with OBDII v2. They will do 95 and 96 ECUs (OBDII v1). With some minor repinning, and changing the rear O2 sensor, the 95/96 ECU works with the 97/98's.

joe

blacksr
12-18-2002, 04:59 PM
local autox guy, takao:
http://www.rfic2003.org/DynoSept02.jpg
bolt-ons and slight port work only, stock 92 ka

**DONOTDELETE**
12-19-2002, 12:47 PM
this is my dyno chart - pretty pathetic...

http://filebox.vt.edu/users/dhuguet/dynome.jpg (pic too large, edited. ~alex)

Mav1178
12-19-2002, 12:56 PM
Seems like something is making your car lose power. Cams installed properly? Head ported properly? Etc?

-alex

jimc-s13
12-19-2002, 09:51 PM
The dyno chart has the right shape, just the numbers are quite low. How does the car feel? Maybe the dyno was inaccurate?

Jim

MATT_BACK_VASS
12-19-2002, 11:56 PM
holy god what is wrong with yoru car

is the stock intake manifold sucking??
is the stock tb sucking??

what gear are you dynoing in ?

**DONOTDELETE**
12-20-2002, 08:25 AM
They dyno'ed the car without me there, and didn't have their A/F meter hooked up. The car definitely feels lacking, and I'm going to some things like:

clean the air filter (K&amp;N)
check timing
check AAC, TB, FICD, MAF, fuel pressure,
check engine temp sensor
check wiring, etc.

then I'll go back and dyno it with the A/F meter to see whether it's running rich...

Dave

MATT_BACK_VASS
12-20-2002, 02:12 PM
get a stand alone system like sds

autocrossing
12-20-2002, 05:58 PM
haha, and while you're at it, get me one too http://forums.freshalloy.com/ubbthreads/images/icons/wink.gif

**DONOTDELETE**
12-23-2002, 09:15 AM
ok, so I checked the timing - it's smack at 20 btdc. Talked to the machine shop, they said they didn't really port it that much, just polish mostly - now I'm wishing I had specified more what I wanted instead of letting Rosen do it all for me. but at the time I didn't know what to ask for...so internally, they just polished stuff mostly, and bored out the cylinders for the pistons, and did a valve job.

jwt says that their cams are identical on both sides, I'm wondering what their specs would effect: .390 lift, 275 duration? or did I get that reversed...I looked again at pdm's cams, and they're much different specs, and the intake/exhaust cams are different. I'm wondering if these JWT cams are not suited to my application and I should get the PDM cams instead...

question though - can one remove cams from the top by just sliding them out of the timing chain sprockets (and not have to take upper timing chain cover off)?

I'm getting a digital multimeter to check out other stuff, and maybe a snap-on scanner to check things also (ebay is awesome)

Greaser - what's your next suggestion?
Dave

Mav1178
12-23-2002, 07:51 PM
</font><blockquote><font class="small[/img]In reply to:</font><hr />
question though - can one remove cams from the top by just sliding them out of the timing chain sprockets (and not have to take upper timing chain cover off)?


[/QUOTE]

You can take the cams out without removing the upper front cover.

-alex

MATT_BACK_VASS
12-24-2002, 12:29 AM
you need more lift