Went to the TJWong's dyno the other day... (Great facility, Tom!!)

However, was disappointed with the results... 266HP/260ftlbs...

We both agreed that it seems to be a breathing problem...

95' LT1, AT

Flow numbers on my heads:

int exh
.10 66.5 55.8
.20 141 112
.30 197 144
.40 235 166
.50 257 180
.55 259 184
.60 260 186
.65 260 189
.70 259 191


My cam is a Comp 224/230 xe grind. 1.6 ProMagnums...

Stock exhaust, Stock Exhaust Manifold, Stock throttle body....

I was hoping to get close to 380HP at the flywheel...

So, what first? Not alot of money left in the coffers...

a) Port Throttle Body to 52mm ($200)
b) New Exhaust ($???)
c) Long Tubes ($500)

What do guys think?

Also, wondering the best method to convert to approx flywheel hp...

Thanks in Advanced!

 

You have a pretty healthy cam and good flowing heads. I would go 58mm on the tb and do full exhaust and long tubes.

260rwhp on a mustang is probably close to 300rwhp on a dynojet.

 

Yup, thats what I was going say as well. Mustang dynos always run lower than dynojets.

 

 

Exhaust, Exhaust, Exhaust.....Long tubes and full exhaust. 58mm Throttlebody and an LT4 intake...

 

Get er breathing. I agree with the above except the LT4 intake won't work on LT1 heads. Hows your tune?!?

 

Haven't done too much tuning yet... When TJWong had it on the dyno, we were watching AFR... Seemed a bit rich but nothing major.... (about 13)

When we are talking exhaust, we talkin' the whole deal? Just don't want to delete the cats...

How much do you think I am leaving on the table right now?

 

Yah mine was on the low side to. Must be his dyno

 

You've got some good heads, and cam.....get some headers! Good high-flowing cats don't hurt too much. I'd think TJ would have some input on this, he seems pretty sharp here on the Forum.

 

That 266hp at the wheels is about 320 hp at the crank, with an A4.

Did the dyno facility have a wide band A/F sensor; if so what did that curve look like.

 

I would agree those numbers suck.
Get an exhaust on there first and re-dyno it. I don't think you need a 58mm tb to run your 350 to 6500 either.
Get a long tube set up and maybe a computer tune and I would think your numbers would increase greatly.
Did you do a compression test to make sure each cylinder is building decent pressure?

Just for sake of comparison to you I dynod 276rwhp 347trq. It was an L98 with stock cam, stock heads with headers, intake and rockers.
I would think your combination with an exhaust should have you somewhere around 350rwhp when it's tuned correctly.

 

Remember this is with a mustang dyno! I am sure you dynoed 276 with a dynojet right?

13:1 is not rich, if anything it is lean. But on a NA motor I would run it no more than 13:1 AFR.

 

I have the hotcam, and headers feeding into the stock exhaust minus cats and dynoed at 355hp on a dynojet. Otherwise I believe we are about the same. Nathan Plemons web page showed a big gain with long tube headers on the LT1 and no gain with a bigger TB. Oh, and by the way, this is on a terrible tune. Its running pig rich.

 

IMO don't waste ur money on a bigger TB. Long tubes are a must. i suggest invest in some high flow cats, get some long tubes and a decent exhaust system. it will be worth it just for the change in sound. also i think the cam may just be wrong for your heads. A tune would help but i think a custom cam is needed.... i only say that cuz i think those numbers.....

 

Okay, then... Here's the plan...

Short term (pending approval by my CWO (Chief Wife Officer))
Long tubes ($350), delete Cats ($0), hook stock exhaust to long tubes ($50-60)...

Long term
Bullet Cats ($500), custom exhaust ($???)

Leave the throttle body alone.

Does this sound reasonable?

 

TankerVette,

You were a little on the lean side during the WOT runs that we made. However our final run at appr: 13:1 was in the ball park. I prefer to tune around a safer 12.5:1 but at 13:1 you are OK. I beleive that there is a considerable amount of power to be squeezed out of your combination. The bottle neck resides in the exhaust system, what goes in must come out. You have drastically improved the induction system, by porting the heads, intake and changing the cam out. But it can't breath because of the exhaust system bottle neck. Also if you send me your TunerCat file I can take a peek at it and see if there is room to grow in the PCM calibration.

A 52mm TB conversion from Dave Kuldos will also help your engine breath. At around $225 or thereabouts its a deal compared to a LPE 58mm TB at aover $500 The other best deal is a Holley 58mm available from Summit for around $350 or $375. I don't like the BBK units, I have had too many problems with them. The Holley units are carved out of billet. Soon Accel will release their LT1 58mm units where I can save those that want one some hard earned cash. They are the exact same as the LPE units.

I haven't had a chance to find that Borla Exhaust system that came off my car yet. But when I do I will let you know. I will of course pass on a deal that even your CWO will approve of

Unfortunately it is true that my Mustang reads a little low. But for the better because I beleive the numbers are more accurate. This debate could go on and on. The main reason is that the Mustang dynos factors in the cars weight and its Hp requirement at 50 MPH. So not only are you spinning up the built in mechanical inertia of the rolls the PAU's add in additional inertia to simulate your car on the road. This is how it calculates the power your car produces on the road in its vehicle simulation. On a Dyno Jet none of this is taken into consideration, so you spin up its mechanical inertia and thats it.

I can however change the correction factors to reflect that of a DynoJet, but then I would just be like them Anyways, the main thing is that we set a standard and stick with it. Othewise if we mess with the corrections, we would not know if the gain or loss of power for your modifications was due to your mods or due to the change in the correction factor.

On another note I tuned a 1970 three door suburban yesterday that had a 434 SBC and a super ram with GEN 6 DFI on it. I can attest without my Mustang I could have never tuned that old G6 system properly. Its the best tool I have ever used for tuning. I could hold it at virtually any cell in the fuel and timing maps and make my changes to make the desired results.

So send me that Tuner Cat file

 

TJWong...

I agree that your machine is da' bomb I would MUCH rather have a conservative, consistant and accurate number...

...it was just a bit of a shock to the system, if you know what I mean...

You went above and beyond, especially considering I was just doing a baseline...

Fellow forum members, you will not find a better combo then TJWong and his friendly neighborhood dyno!

 

In your first post, you mentioned LTs as an option for "($500)"...in a later post, you say "$350". Now, I dunno what your smokin', but it's gonna cost you way more than that for LT headers! First of all, you want to go with a quality set of headers - I don't want to start the "what brand?" arguement, but let's just say that you get what you pay for out there.

After you purchase the headers, you're still looking at installation prices. Let's just assume for the heck of it that you can do 100% of the work, O2 bung welding, etc. yourself. You still need custom pipes made to go between the headers & your catback, a new set of gaskets (FelPro), and some good locking header bolts (Stage 8).

Don't get me wrong, I *highly* recommed LTs as a worthy mod - I just don't want you to go into it thinking it's inexpensive because somebody might've told you that or something. Know what I mean? At any rate, best of luck with whichever route you take.

 

ur setup is identica to mine- compcam 224/230- ported heads- 1.6rr- i also added electric waterpump- i hope mine doesnt show this low- i cant really feel much of a diff in mine from b4- i called comp and they said with my 2.59gears i may not feel anything- but i dont think this could affect ur #s'-

im just saying i know how ya feel- spend over 2k and come out with hardly nothing

even with exhaust u ill be lucky to get 30 more hp- i think its a tuning issue

 

perfusion...

this is where i was getting the info...

http://forums.corvetteforum.com/showthread.php?t=930283

would definately love to get the EM's stainless, just can't afford it right now...

If I can put something less expensive on it for now and get it to breathe, we can look at upgrading in the future...