Low numbers ...Where to start troubleshooting
 

I have a fd with:

Street port-unknown size(mid-large)
garrett t67
3in dp
catted mid
hi power hks muffler
apexi pfc
stock mount xs ic
kg 160lbs
stock primaries
3bar map
50mm wg dumped
fpr
manual trans w/ new clutch


Tuned by Brian at Rotorsports
95-97 at dyno humid
made 320 at 15 psi
ran to 6500 rpm (6700 starts to fall)
mustang dyno
Graphs not have af but Brain said they are mostly tens with some low elevens

Car runs strong but from my research i should at least be low 400s

catted midpipe could be part of it... if you cant remove the cat for emission reasons, at least check to see if its clogged.
you could always put in a catless midpipe , then just switch back to the catted pipe when you go for emissions testing.

Dyno
 

Here dyno sheets

Anyone know were to start or what may be wrong?:scratch:

no testing here but kept to quite it some ....getting rb catback bc still to loud...

Ill check it thou!
thx

Make or purchase a boost leak tester and verify no leaks. www.boostpro.net/prodtester.html (universal tester at bottom). you can make it out of PVC.

Hard to tell from those graphs but it looks real laggy. Do you know when your getting full boost?
Sounds like you could lean it out a little more and Mustang Dynos read low.
I would take it to a dynojet and have them hook up the wideband and boost readings. That will give you a better idea of where you are.

I would also stick a HKS Twin Power on it.

if youve got no emissions testing in your area, then there is no reason at all to have a cat. the stock cat is only designed to flow for stock power levels, and even then was not adequate. even the expensive "high flow" performance cats have some small detriment to flow, since they are an obstruction in the exhaust path. the only reason to use them is people that live in a place with strict testing. with a cat-less system and magnaflow midpipe and RB exhaust, i dont get the "rx7 smell" that some people worry about (i did have that smell with just a straight open midpipe though).

backpressure caused by the cat reduces both power, and spool.
even if there is another problem with the car causing the low power, i would still remove/replace the cat.
you can get a resonated or muffled midpipe with a straight through design, theyre fairly cheap and well worth it.

also, as arghx mentioned, boost leaks are a common culprit as well.

other things can be ignition, as jason mentioned, and related stuff like old spark plugs, old plug wires.

plugs have 8k wires prob 15k.

looking for rb muffler...thread in wtb/wtt section

also will check cat!

think full boost was bwtn 3-3500

how do i make a boost leak tester? researching now!

boost guage holds...shouldnt it fall if it was leaking?

So you made a boost leak tester and it holds? How much did you pump it up?

no sorry meant when dynoed boost held and driving around holds.

Found write up on how to make tester. Will look into purchasing stuff if i can use a friends compressor.

key to remember with a boost leak tester: you are not actually trying to pump the system up and make it hold pressure like you would when testing say a fuel system. The engine isn't completely sealed. Rather you are pushing enough air through it that you will be able to feel or hear air escaping. Another thing to do is spray slightly soapy water through the engine bay while you are testing to look for bubbles.

now that i think about it that might be when it came on on the dyno....

ill see wht it is when drive it again.

Plan to leak test and check cat and ill get back w yall

thx again:icon_tup:

catback should be in today or tom. so boost test, vac test, cat check will be done.

I have been researching and researching in the mean time.

I read and have seen videos of dumped wastegates and they all say its very loud when it opens. Mine has never been loud. What would that mean-No enough pressure to open it? or air flow is poor or wastegate too big?

Sorry to sound like a newbie here but I not know much about wastegates-learning and searching.

Any info helpful!

thx

Comparing others dyno numers is like comParing apples to oranges. I pretty much have the same setup and made 400whp at 20psi on a mustang dyno. Now on a dynojet or other dyno my car would prob be around 450-475. If it runs good and strong just leave it

On your setup I would say its because there really isn't that much "airflow" through the engine. In my experience if you're not near the edge of compressor's max output, the higher the rwhp the louder the waste-gate is.

Sounds like you're on the right path to figuring it out.

I made the same amount of power at 14psi. We have the same turbo and try don't start really breathing well till 18psi+

thx rxspeed7

what other mods do you have?

why would the boost stop at 15 psi? ebc not seem to raise it any...gauge is not dead on with commander. EBC nob is almost maxed out on high

if you're going to complain about power output then you first need to ditch the cat, the figures are not that bad actually for being a catted exhaust car.

that will help with peak power beyond 6500 but the root issue is as people mentioned, sounds like you have a boost leak or a faulty wastegate system that isn't holding pressure properly.

if you eliminate the cat and hold boost up to ~7500 i can easily envision you picking up another 50-75 horsepower at the least.

cat is a banzia main cat-not clogged.

putting rb on and hope to get stuff to boost leak test

my car is as follows
13b-re 9.4:1 NA rotating assembly
microtech lt10s
precision 6776e
hks log manifold
3.5dp to old school racing beat rev1 exh
1680cc sec, 800cc pri

cat is holding you back a good amount. also mustang dynos read low and as some others have said the number doesnt matter only actual horsepower meter is the 1/4 mile trap speed.

Ur car is probably fine. I can say it probably the tune. My car and a few of my buddies also get our cars tuned by Bryan. He is a great tuner but very conservative. Ur car will last for a long time if he built and tuned it. Power is gonna be a little lower than the next person, but it will be safe. My numbers were way off from what other setups using the s475 had. I only did 391@15 psi, where as others were in the low 400's. And I did 435@17 and 466@19. Everyone said my numbers are low, and I agree. But I have beat on my car daily. But do the exhaust first, and then maybe try a re-tune. Bryan is gonna stay in the low to mid 400 range for safety reasons. He not a race tune big boost kinda guy. Mid 400's and enjoy the car.

Thanks for replies guys!