so,i took my car down,meet up with some local rx 7 guys and put my car on the dyno to get a base line so i can compare stuff once i get my microtech installed.
big disapointment-very big...
basically,i have had my motor rebuilt,with[supposed]s5 internals,t2 intermidiate housing,mild port,converted it to s5 intake manifold[ported],and installed a mazdatrix style full dual exhaust[homemade with rb parts],put it on a dyno and cranked out a whooping 122.9hp[6800rpm] 104.5 ft.pds.boy,that would be decent stock,huh.
so,here is some questions-if the shop f$%#@$ up and put turbo rotors instead of h.comp.n/a rotors in,is there any way to check w/o pulling the motor appart?the car is running rich,its at 13.7 a/f till 3.8k,then spikes way lean to15.5[!!][i'm thinking the mt will take care of this,there is obviously a fuel problem there,a big loss of hp "dip"]comes back down to 14 by 4.8k and then drops consistently down to 12.5 by 6.8k.i guess is this messed up enough to cause my results?the big midrange "hickup" should not have any top hp # effects,i would think,and i thought i should pull at least 140-50 hp easy.anyways,any1 have any input?this sucks.i guess it will be really interesting to see what happens with the stand alone,thou.

david
ps:i might try to scan my sheet and post it for you guys to check out,if i have time.

 

Jeez, that's bad! Do you still have your 5th & 6th ports? If so, do they still work? that looks like they're stuck closed or something.

 

yeah,they are opened via exhaust backpressure,and somebody visualy verified them opening[a bit late at 4.2k or so]while i was on the dyno.i have the pineapple inserts,as well.
~d

 

Wow, something is definatly not right with that! Maybe you're having a hang-up with the secondaries coming online.

 

yeah,that might be part of my problem-definately when they come on at 3800-the car momentarely leans way out.but,by the time 7k comes around the mixture is about 12.5 to 1,wich would be pretty rich for a n/a,right?

 

the rich/lean thing is kinda normal for our cars. It sounds to me that you might have low kompresion rotors BUT!
1. if your exhaust is open way much, it could be power loss! (you mention MT true duals with RB, that might be the problem)
2. Check your grounds, if you feel hesitation at 3800 thats because bad grounding, you cant possibly feel acurators opening! they start to open at 2500 and they should be fully open at 3800
3. NA has 146 HP at flywheel, If you count 30-40 hp power loss at tranny+shaft+diff you get exactly what you've got

botom line: you car could be running correct after all.

 

What about the VDI?

 

all the piping is the same size as the MT duals,presilencers and mufflers.why would it couse power loss in my car and big gains in everyone elses?i reved to 7200rpm,and you can actually start to see the power band drop off again.this does not make to much sense to me...
i actually have added a bunch of grounds,but like i mentiond i do have some hesitation issues in the midrange.
like i sayd,i had somebody visualy verify that they open.a few hundred rpm late should not couse any big loss in the top end
yeah,a s4 stock.but a ported s5 with a full exhaust should be more.guys with similar setups are pulling 160 rwhp

~d

 

thats with the vdi wired open.my first pull was w/o the vdi open,and i made about 110 hp.

~d

 

crap compression? frog in your intake?

 

maybe the dyno wasn't calibrated right?? Are you sure those guys that were operating it knew what they were doing??? I mean for all that stuff you got on, you're putting out like stock levels. (Now you got me worried that I spent all this money for nothing)

 

your putting a stand alone on na? for a na your Hp is right around it should be.

 

No one is happy when they put their car on the dyno. It is like taking a big test that you are not ready for but you cram the night before anyway and when you get it back you flunked it. I will agree with RyosukeTakahashi there dyno might not be calibrated properly. What style dyno are they using?

Lets put it this way you drove the car before you did the motor work right? And you drove it afterward, did you feel a difference? Here is the big question, does it make you happy when you drive it? Then don't trip . Dyno's are evil.

But yes I agree with you. You should be making just about 160 at the wheels. I was at a local dyno day where a person (Sully on the forum) had almost the exact same set up as you except he still had the S4 intake. First run 120 something. After I wired up the 5th and 6th ports with a zip tie he got 150 something (getting old memory failing) So with the S5 intake you should be pulling around 160.

- Rotary Race "Come in loving your car, leave hating it"

 

Well too much fuel and you will loose hp, same goes for not enough fuel, same thing with fuel pressure. Get a safc and start tunning. That is NOT normal for a NA, 140 is the normal hp for a FC with I\H\E......

BTW - Did you change the spark plugs before the dyno?

 

def. a low output...if 5th and 6th ports are working check your AFM and look for vacuum leaks.

 

Was that SAE corrected horsepower? What is the elevation of the dnyo?

What was the temp?

James

 

122 is kinda discouraging...with a port job and full exhuast it should put you up, let alone you're using t2 internals.

when did you get it rebuilt? still in break in period?

 

They jumped the on the boosted bandwagon.

 

well,i suppose the dyno could have been off-but,jerk racer pulled 300+hp right before me,wich he was real happy about.the ambient temp was pretty cool,it was a coldy rainy evening in the pac. northwest with all doors wide open and a big fan blowing,my oil and water temps where very normal.elevation is next to sealevel here.not sure what you call'em,but it was one of those dynos you drive on and they lift the car up.i made 3 pulls,and the 2 with the vdi wired open where almost the same.
i did not have time to install new sparkplugs,just a oil change.
and,yeah,i was a bit let down with the performance after the rebuild-the thing is,my car was a absolute dog before,[no compression]and i changed everything over at once,so no step by step comparison.
the motor was broken in properly and has been driven on for about 1 year.
and,yes sae corrected #'s.
i guess i will go ahed and install the micro tech,wich will eliminate afm problems,stick in some new spark plugs and see what happens.and do a compresion check.
what comp. #'s should i be seeing?and,i suppose there is no way to determine if they messed up and installed low comp.rotors,right?thanks for the input,thou,guys.
david

 

I know someone with a completely stock S4 N/A that put down 122rwhp, and 118rwtq. Von on this forum put down 160RWHP on a S5 N/A with just bolt-ons and some intake(manifold) porting. With your mods Id think you should be seeing the high side of 190rwhp... Something is definately screwey...

 

Isnt the S4 intake better for ported motors?? Or does it not matter as much because its only a mild port(why would you do that anyways?)

 

my point exactely.i think i unhinged my jaw when they told me 110hp after the first run.

 

same problem with my car... i came to one ... of many...conclusions that altitude might ultimately affect what you are pushing at the wheels......... if it does or not i have no idea ......
good luck with your problem...
edwin

 

Did anyone else dyno with you that day to compare to?

what kind of dyno was it? Dynojet? Or was it a Mustang dyno?

Mustang dyno's read lower than dynojet. They are more accurate for hp changes, but read lower overall. I found this out first hand with my old car, where I dyno'd about 25whp lower on a Mustang dyno, than I should've on a dynojet.

Now if you used a dynojet, then that shoots my theory right in the ***. *shrug*

 

well,since the dyno was done at almost sealevel,that should have worked in my favor...