Trick Flow Top End Kit user's, please step inside

^ oh hell yeah man i agree about the tune. Dont get me wrong, my car runs good without a tune but Im just waitin on a tweecer that I asked for for christmas lol

A tune is a good idea, but typically those engines will run stronger than that.

Now, if your elevation was not corrected, I think that can be much of the "missing" power you think you should have.

A tune is always going to help you out, in this case.

This was mine before a retune,longtubes and a bigger maf.

So you gained roughly 40 RWHP and 50 RWTQ from just those mods?

I'm guessing the bigger MAF and longtubes were only worth about 15 of that. Leaving the other 25 RWHP gain from the tune. Pretty impressive.

I'd love to get rid of the shorties and cat's, but mine is daily driven and has to go through emissions regularly. I didn't wan't to have to swap exhaust every year. And since my car is lowered, I didn't want to sacrifice anymore ground clearance for the longtubes.

Mine is lower with h&r ss vert springs.No issues on scaping as far as longtubes go.Emissions just get a catted pipe for the longtubes.

Actually the maf was worth 6rwhp in itself after tweaking the air/fuel to get it back 13:1


Comparison before and after:

I got a thought or two here

Sure a tune would help
but
Similar combos with no tune that made more power are available

If you got high flow cats ...
I don't see them holding you back much ... 3 to 5 rwhp for a ball park value

I believe I've seen it said cats will show around .75 of one point leaner if a
sniffer wb has been used ... but ... my memory is fuzzy about that amount.

however ... I do know leaner results will be seen

I gotta believe something simple is at fault here
and
My gut tells me you need more fuel

I feel 24's for an aftermarket h/c/i combo are close to the limit
and
All the more so at OEM fuel pressure :Word:

The thing someone told you about O2's being in effect at WOT is not true

If you were to reset your pcm before a dyno pull or 1/4 mile blast .....
The pcm would not have had the amount of time it needed to make
changes to compensate for elevated fuel pressure due to an afpr

Grady

Well i agree and disagree..Shorty headers and cats are not the making of a good combo,regardless..Esp on a good h/c/i car.

24's are close to the 85% duty cycle on a 300rwhp combo, i know i datalogged mine with a SNeec.. So i agree bigger is better but are still ok if you are in the high 200's or low 300's.

A tune will always help,because reguardless of what 500 other peaple post,every car reacts different to mods.Even though the ecu is still the same number..Ever wonder why some cars were faster than others even stock..Glitches in the machine..


If i had listen to the 500 different answers i read though on why my combo did not make the power i wanted out of the box.I would have gave up,but instead researched and did my homework..Because 9 times out of 10 ,everyone says you need afr or tw heads to make power.

But unless we know the EXACT details,
fuel pressure
fuel pump(fuel filter ever been replaced)
timing (total and across the board)
deck height (5.0's are known NOT to be square)combined with gaskets used
how much the cats are actually flowing(high flow cats have a pretty short life span - 1~3 years tops -depending on the air/fuel mixture speeds this up)
a/f BEFORE the cats
if the cam was degreed in or just installed dot to dot
Hell it could be a dyno operator error,some do this to make others think they are getting a awesome tune by that company.

All this matters.This is just some of the variables in a combo

Killercanary was running 82% duty cycle with 24 lb injectors running 356rwhp on his 331.

It is not all based on strickly horsepower

39psi fuel pressure.
New fuel filter.
255lph Walbro pump.
18 degree's initial timing(stock distributor and A9T ECU).
Fel-Pro 9333 head gaskets.
Cat's have about 3K miles on them.
14:1 AFR was measured after the cats at the tail pipes.
Cam was set straight up, dot to dot.

The timing curves in the a9t could be something to look at.

Personally , with the current mods i think you are where you should be.
Figure 20+ rwhp with longtubes and highflow cats.
10+rwhp in the tune a few more if you open up the mass air meter(plus you wil gain better drivability with a ford maf like the lightning mass air.

My car picked up 10+rwhp on tune alone (before longtubes and new meter).
But the car drove great ,just stalled every once in awhile.

I have say, I do not believe the final "peak" number is hurt by the shorties, if they are aftermarket. The lower torque/horsepower values, yet, but not the upper rpm range.

Getting rid of cats is something I would look into, plus it is lighter.

This is all if you do not have to pass emissions.

You know im going to have to disagree since i know what mine picked up..But like ive said before every car reacts different.

There is a good 30+ horsepower left in the combo,esp with a higher flowing exhaust and tune..But its up to the OP what he wants to do.

Your right, I knew you would, but that is cool

My car did not react anywhere near the way yours did after a longtube swap. I felt a little more down low, but mid range and up, nothing. The track showed it too.

For exhaust, I have BBK 1 5/8" unequal ceramic coated shorties going into a 2 1/2" BBK high flow catted H going into a 2 1/2" Flowmaster Delta Flow aftercat. I can't see longtubes and no cats making much of a difference over that. Certainly not 20+ RWHP.

For intake, I have the stock airbox with a flat panel K&N going into a C&L 76mm MAF meter with a C&L 76mm inlet pipe.

No driveability issues. Car doesn't stall or stumble. It's a little lazy below 3K, but it pulls hard to 6K after that.

I have seen different TFS combinations get near the 300 rwhp without longtubes. But I did see that they all were "catless."

Longtubes will help boost that "laziness" below 3,000 that you speak of. Most of that is the camshaft's position as well.

Mine was fms shorty headers into a o/r hpipe feeding a flowmaster catback . Stock air box into a 80mm lmaf then upgraded to a 90mm lmaf feeding a 76mm inlet pipe.
Mine ran great besides a stall here or there.



Not my car,just letting you know there is power on the table..On my own i seen a big increase -posted the dynos to show you ,on my 99 longtubes netted me 15rwhp over shorties on a stock 4.6(which has less cubes than the 5.0)..SO im two for two on longtube gains on two different stangs.

I agree, ive seen some cars make close to 300rwhp on shorties but like i said before there are freaks out there,where everything just is at the exact tolerance when it was built.


But if longtubes dont make a difference why then do all racers use them,even the factory stock guys?Esp since most say they only help down low...I dont see any of those guys below 4k at the track.

If the combo is right they will help the whole curve..
Also like stated earlier cam timing makes a difference also..You installed it dot to dot..SO if the tolerances of the cam maker ,timing chain,factory key way are off a little(one way or the other all stacked up ) this will also throw off the curve of the engine,because the cam timing is either retarded or advanced.

Degreed mine ,its less than 1/2 degree off..
Im not one of the internet racers and book readers.I have been building mustangs since 86 and Chevy's before that.If i didnt do my research and check with the real peaple making power(i know insiders at ford the company ) .I wouldnt have the combos ive built to date..Hell at one point i was one of 10 2v's making 500+rwhp ,and the only one NOT built by a shop.

I have given advice ,so have others that is also good,its up to you what you think you should do..

If one is willing to go with longtubes, with the couple problems they can pose, I say do it, with no doubt

I am just letting you know that the difference between each at the track is not going to be dramatic.

Racers use anything and everything to give them any kind of edge they can get.

Just do not expect crazy amounts of difference.

I added a new 306 (with .1 more compression than before if I recall), had the lower ported by tmoss to match the AFR 165's, and then added NEW longtubes, over an OLD dented set of Mac's.

I gained 1.3 mph with all of that, even a few thousand miles after the break-in. That is roughly the equivalent of 13 HP.

Longtubes do sound better as well.

Since we're talking about dyno's, here's an email I sent to Dynojet:


Does atmospheric conditions and elevation effect horsepower readings? For instance, say you dyno a car when the temperature is hot(say 100 degree's) and then dyno it again later in that same day when the temp is 60 degrees. Would the temperature effect the horsepower numbers? Or would the numbers be the same due to a correction factor, say like the SAE setting? Also would a car read less horsepower if it was at a higher elevation than it would if it were at a lower elevation on the same dyno?



Here's their reply:


You have touched on the whole purpose of the Correction Factors. The various formulas, SAE, STD, JPN, etc. are all mathematical formulas that take into account the various weather conditions and try to ‘correct’ the measured output on the Dynojet to the projected equivalent if the test was performed under ideal conditions. So, if the temp, pressure or humidity does change, theoretically it will be accounted for and offset by the chosen atmospheric correction factor. In the US, the SAE correction factor is thought of as the most widely used.

These factors do ‘assume’ that the vehicle is properly tuned for the particular conditions, for instance a carbureted engine that is set up for seal level, would need adjustments when moved and then tested at higher elevations. But, if all the engine management parameters are correctly dialed in, and proper dyno testing procedures are followed, the power from one day to the next should remain equivalent.



Keith Royle

Director of Dynamometer Sales

Dynojet Research Inc.

800-992-3525 xt 1121