I think somethings wrong here but do these numbers seenm a little low to you guys. I mena 300 to the wheels with the mods I have done? My FAST setup was tuned by a very reputable dyno tuner. These numbers are off a Mustang chassis dyno.


383 10:1 cr
AFR 190 heads w/ 62CC (I think)
Comps cam 224/230 .503/.510 110 CL
HSR
Holly 58MM TB
FMS 30lb injectors
SLP 1 3/4" headers SLP ypipe no cats, B&B tri flow cat back
MSD ignition with timing at 6 degreess( due to the FAST ECU)
Harland sharp 1.5RR
FASt B2B ECU

Here some some numbers off my dyno sheets, remember these number are from a Mustang chassis dyno.
----------------------min---- max----- Avg.
Total Power(HP) 116----- 298----- 232
AFR(ratio)-------- 13.5-- --14.6---- 13.8
Torque------------ 284----- 340----- 317
Temp (deg F)------97.9----98.2--- -98.1
Pressure (InHg)-- 29.44--29.48- -29.46
Rel Humidity (%)- 62.3--- 62.7--- -62.5

RPM----Total Pwr (hp)-- AFR---Torque-- Temp--press--humidity
2080----118------------- 14.5--- 295------ 98---- 29------ 62
3080----189------------- 13.7--- 323------ 98-----29------ 62
4080----264------------- 13.8--- 339------ 98---- 29------ 62
4180----264------------- 13.4--- 340------ 98---- 29------ 62
4280----276------------- 13.8--- 339
4480----285------------- 13.8--- 334
4680----291------------- 13.9--- 328
4800----293------------- 13.9--- 315
5000----295------------- 13.8--- 304
5200----298------------- 13.7--- 297
5300----296------------- 13.6--- 289
5400----294------------- 13.5--- 284

Look closely at the RPM range, I skipped a few in the low range.if numbers are missing in the chart it is because they are the same all the way down the list


sorry if this is in the wrong section but I didnt know where to post it.

 

yup, 300rwhp out of that combo you listed is DEFINITELY not good! From what i'm seeing from your dyno report, two things are hurting you so far: that 6* of timing is no where near optimal for a N/A motor so your leaving hp and torque on the table right there and second, that motor is RUNNING LEAN AS HELL! its running at nearly part throttle air/fuel ratios @ WOT. I bet if you get the timing up to around 32-36* total (depending on what the motor responds to best) and shoot for about 12:5-12:8 AFR @ WOT you'll see a completely different 383. A fuel pressure regulator is a good investment if you don't have one.

 

I don't think you know what your compression is, which means other details might have been overlooked.

What pistons, head gasket, chamber size and deck height are you running?

A mis-matched combo will always be down on power, no matter how expensive the parts you throw at it.

 

well I just went and looked through all the paper I got from the tuner to see if it gave me any more info as to what kind of work was done on the dyno. my bill says: 2.5 hours of tuning acceleration and full power sweeps, tune for best average torque and power. SAFE TUNE. 1 hour of part throttle and cruise drivibility.

The tuner said that the fuel pressure was dead on for his tune and I have 2 gauges to read the pressre. I dont know what it is right now. I would have to wait until the weekend to check it out. I am going to have to see what this safe tune is all about. I am also going to get a few passes on a dynojet and see what it reads.
as for the timing. It clearly says in the FAST instructions to set the timing at the factory setting of 6 degrees. The ECU controls the timing from there.

 

Your AFR is too lean. You want to be near 12.8 for best overall results on the dyno. You need more fuel at WOT. I would expect that you had some or alot of KR. If you have an AFPR, turn it up 4 psi and see how the engine response.

Was any data logging of engine functions done while on the dyno?

 

if datalogging was done the the tuner didnt give me any print outs and he did not use my laptop. as for my CR, the kit I got states that with a 74cc head, I should see a 9.7CR. My AFR heads are 76cc and then I had them cleaned up a bit so Im sure they went down a cc or so. I am running a standard felpro gasket for the SBC with aluminum heads. I think the number was 1010 maybe. my deck height is stock. it was never messed with.

 

You have the FAST engine management system, how is that working out for you? Cant you tune that yourself?

I dont know why you bring up CR when I talked about AFR.
A CR of 9.7 might allow you to run lower octane fuel. I dont think that this has alot to do with having the right AFR for peak Hp numbers. But then, I am far from an expect.

 

yes I can tune the FAST ECU myself but I am a novice at it right now and I dont want to mess stuff up. plus I can't tune anything w/o being on the dyno anyway. I mentioned my CR because 89gta383 ask about it.

 

BTW: You have a GREAT looking car ! ! ! !

 

EFI tuning is not as difficult as it might seem. At first, I felt that way, but then bought the Eprom programming stuff that you can research on this board and started to tune myself.

Just keep in mind, its air, fuel, and spark. I think its easier to tune an EFI engine VS a carb.

For example: You need about 5 to 7% more fuel at WOT. The FAST system should have a table by the name (or close to this) "% more fuel at WOT VS. RPM... This might be a single array table, simply % added fuel VS engine RPM or it could be a two dimensional array (like an Excel spread sheet) MAP value on the vertical axis and engine RPM on the horizontal axis,, inside each box then is the value of % added fuel. You select the cells that you decide to change and add more fuel.

Also, only make a change to one table at a time. And take notes. This is what I do.

You should have a tuning manual from FAST, check it out. You can get a ton of help on this on the tuning board on thirdgen.

BTW: A AFR of 13.7 is NOT a safe tune! What is this tuner thinking? I would ask for my money back.

 

Looks like your peak power is around 5200 rpm. IMHO that is low for the cam and HSR that you have. Something is not allowing the motor to breathe properly. Was the cam installed straight up or advanced or what. Describe your intake system from the air filter to the throttle body.

Also I believe you could have used a little more compression but that is water under the bridge. I don't think you are going to gain to much horsepower by richening the mixture. Your safety margin will increase though. Also the Mustang dyno's tend to read lower.

You might try another dyno to get another reading. If there is a track in the area make some passes down the track. That will give you an idea of the power your car has.

 

98 degrees F? Well thats not right... not in MA in the dead of winter. Sure hope this wasnt a recent test.

 

Well, as a point of reference, I made 340RWHP with the same cam, a 350, 1 5/8" headers, no WOT tuning, trickflow heads and a Super Ram.

 

i have damn near same setup, just a bit higher cr, and next step up cam, and im shooting for 400 to the wheel.

 

It more like about a point lean in the AFR department.

I'm not a real fan of the 13-13.5 AFR I see lots of people tuning for. When it works, it only tends to work for one pass or pull. Try sustained 3rd or 4th gear pulls or hot lapping and watch what happens.

Nother thing the AFR is even leaner when the pull started and stays lean therafter(in my opinion). Did it start knocking and continue to do so thruout the run?

Also I can believe the humidity is 60% and the pressure is 29hg, but why is the temp at 98 and your in Mass?

Post the dyno charts/graphs if u have them

later
Jeremy

 

My calculations based on what you said above give me 9.5:1 compression and 7.69:1 dynamic compression. Your quench is .066.

These things might not be the main reason that your combo isn't making the power you want, but all the details add up, and you need all the details to be addressed if you want to get the most power out of your combo.

Like I said, a mis-matched combo won't make power no matter how many expensive parts you throw at it. I know from experience.

 

After running a few vehicles a cross the treadmill, indoors, with exhaust scavengers connected, the indoor (ambient) temperature could be pretty damned high. Radiator heat rejection alone could heat a small shopping center.

 

its on a mustang dyno... mustangs will read lower than a dyno jet. i'd say on a dyno jet your more like 350rwhp. which aint bad at all with that cam. peak at 5200 seems a tad bit low.. i'd think it would be 5400-5500 range.

get the air fuel ratio more in the 12's and then you should see some power improvements... 320rwhp on that dyno i'd say.

on a mustang dyno, thats pretty stout.

 

I too would like to know what the cam is installed at (centerline degree). - To me that seems a tad bit of a small cam for a 383, but I would still expect higher numbers.

 

the cam was probably just stuffed in.

 

i was thinking the same thing.



anyhoo... with just the info presented... its almost impossible to tell you anything conclusive.

we can all make random guesses if you want. lol.

 

First off, you were on a Mustang dyno. I drove my car from a Mustang dyno, to a dynojet 240C, and I picked up 66 RWHP. So, you're really making closer to 350 than 300 on the most common dyno.

Get it to the track, dyno's aren't the be all end all of performance. If the calibration was out of whack, the operator wasn't paying attention, there are lots of things that can mess with the numbers. If it runs 12.0's at 117, who really cares if the dyno says it only makes 300 HP?

 

Thats fine and all, but it still overlooks the fact that his AFR is over a point too lean in some locations. Then it becomes a healthy engine issue.

 

This tune was done last summer and I havent got the car running on the road as of yet. it was very hot outside while the car was at the shop so the 98 degress is correct. As for the cam, it was installed straight up. dot to dot.

 

FYI, I ran my old '89 IROC on a Mustang, then a Dynojet. The Mustang said 218whp corrected, and the Dynojet said 220whp corrected.

You can't say they're always a certain number higher, or a certain number lower, or even say that they're always the same.

I wouldn't tune for 13.8 WOT AFR either, more power or not.

 

So your saying that my tuner may have tuned my engine more for drivibility, reliability, and durability rather then a full blown out ***** to the wall on the ragged edge tune? And this is why the numbers look the way they do? I remember that the first time I spoke to him he asked me how I was going to drive the car. I told him every single day, proberbly about 40 miles a day and more on the weekends. He had told me a few things about how he tunes and stuff and I took his word that all was good. When my car was done, he laughed at me when he seen my reaction to him telling me that I got 300 rwhp. he said "go drive it". He said that 300 was very respectable on his dyno since it factors in a more life like driving experiance or something. I mean the car does feel fast as all heck when I drive it around the neighborhood but I am still scratching my head on the 300hp number. I have done some looking around and I am going to take my car to another shop with a dynojet and someone whop tunes the FAST ECU and see happens. I just dont want to pay a lot more money for someone to tell me that everything in my tune look great for a daily driven car. I paid $700 for my inital tune.

also getting back to my CR numbers the 89gta383 posted " My calculations based on what you said above give me 9.5:1 compression and 7.69:1 dynamic compression. Your quench is .066." can someone tell me if these numbers are good or not. What is dynamic compression

 

LOL, this has to be the funniest thing I've ever seen.

No, the opposite. Your AFR "should" be lower. You're running on the ragged edge. If it was 13.1 it would be safer. High 12s to low 13s for the AFR is the general target.

And almost everyone in the thread has said it. You just seem to be misunderstanding that point repeatedly for whatever reason.

I can understand the high 13s AFR if you had cats and it was recorded through a tailpipe monitor.

Just go find a local dyno day and do some pulls and see what you get.

Dynamic compression is based on your static compression and your cam profile. I personally think it's low and should be in the low 8s:1. When you run a "big" cam your DCR drops. To make up for it, you bump the SCR.

Here's a google for you. I haven't read it, but it's not that hard to understand. http://www.kennedysdynotune.com/Dyna...ion%20Tech.htm

 

Exactly. 14.7:1 is stoichiometric (ie: chemically perfect), but at WOT you have to richen it up quite a bit for long-term safety (cooling), and to resist detonation. I've never heard of an engine running optimally on a 14.7:1 AFR at WOT.

As everyone said, people typically tune for 12.5ish on N/A combos such as these, and some people lose power going leaner for some reason, even without knock. Boosted engines need to run even richer. My Talon likes around 11.0 on 93 octane with 22 psi, and ~11.5 on 110 octane with 24 psi (though it needs a better intercooler).

Anyway, here's another question. Was a wideband used that was inserted before a cat?

Like others have said, the reading may be off compared to other dyno's, but it may not.

.066 quench isn't too bad, but isn't perfect. Ideally you want as little clearance as possible while keeping the pistons from smacking the heads. The common safe number to shoot for is .040. My 350 is at .033 and has no problems revving to 5500.
This causes the fuel and air to mix more completely due to the shockwave created by the instant, close squeeze of the mixture between the piston and head surface. It also depends on piston head design, as well as head chamber design as to how well it works. I can't see yours, so I can't say for sure if yours can get the most out of quench. Basically, the flatter the piston is where it meets with the (flat) head deck, the better it will squeeze.

For much less than $700, you can buy all the tuning and datalogging software/hardware and research (here) you need to get a better tune over time than someone can get on just a couple dyno pulls, and it's fun.

 

- he doesn't have any software to buy, since he's on the FAST ecu. -

as for the cam, straight up doesn't mean much. If you don't degree it in w/ a degree wheel, you don't know where its at. Different manufactures, different grinding techniques, different timing sets, different blocks....etc can all change what degree the cam is actually at. You may be ground on a 112, but may be in at 110. I've seen as much as 5 degrees, and this was a new cam and timing set. -

I do think you outta start playing w/ your tune yourself and try some ddifferent settings...

 

and $7 beans for a tune w/ a dfi system is a rip!

 

Do some wide wot runs and look at your plugs.
Just because one dyno's wb o2 reads 13.5:1 afr does'nt mean for 100% certain you are indeed running 13.5:1 afr.

I also agree with running it down the strip to see what kind of mph you trap.

 

Exactly what I was thinking. Fix your AFR to start with and then think about whats choking you up top. The HSR likes to be pulled to higher rpm's.

 

i highly agree with you, when my machinist installed my comp cams, the cam was 12 degrees off!

get that **** degree'd!

 

Right. Even better.

 

if the cam is in advanced, say 110 instead of 112, that would cause the motor to peak earlier....

also, chassis dyno's are flakey. You can change the tension in the tie-downs and come up with a different numbers....RUN THAT THING!!!!!

 

thanks for the input guys, I will heading to a different tuner a few weeks and see what I come up. As for the track, that will be a little while later since the car is not complete as of now. As for the $700 it cost me for the tune, it was $500. I just looked at me bill and there was extra labor in there for other work that had ot be done on my engine. also, I think Iam going to pick up a degree wheel and set what my cam is at. The engine is in the car so it will be a little harder to do this but I will give it a shot. I just gotta pull the pushords off the cam right?

 

I agree with neat, after checking the A/F out, run it down the track. Dyno #'s can be very humbling, but doesnt mean it isnt a strong street car.
Another vote for the 'Jet giving higher readings. I laughed at my dyno sheet when I saw it but it runs pretty hard for what it is, thats all that matters. I look at dyno sheets the same way I do time sips....A basic tool to track progress, not an end all/be all. Let the 700hp guys brag about the dyno sheets, half of them will never go down the track in their lifetime.
Good luck

 

you need a degree wheel and a dial-bore-gauge to accurately degree the cam. - you can pick up the dial-bore and the magnetic mount for it cheap from Harbor Freight/other low-buck tool stores. - you don't have to have the push rods off. - You do need to know true top-dead-center of #1 piston though. 100% true, not just factory type timing marks. Most cam manufactures have the info on how to porperly degree the cam.

- why head to another tuner? You've got a base-line with the tune you have, time to learn a little about your FAST system....

 

Im not looking to head to another tuner for a retune. I just want a second opinon on the tune I have now. I may learn something from talking to various tuners of the FAST system. I have read alot about the FAST ECU but I am afriad of making changes right now sincer I dont have access to a dyno and I am also adding a few ther parts that I have lying around. Once all my parts are added, I will retune it at the tuner and see what I get and then mess with things on my own.

 

Did you ever think that the single 3" y-pipe might be choking off power considerably. My ZZ4 with HOT cam, ported heads, and larger valves only put out 296.6 on a Mustang dyno. I blame that mostly on my SLP 3" y-pipe. BTW, 13.8 to 1 AFR is best for peak torque. 12.5 to 1 AFR is a safety number. Shoot for 880MV on a standard 1 volt oxygen sensor and you will be right on at 13.8 to 1. A 383's main advantage is low rpm torque. Look at the area under the torque curve and don't worry so much about peak #'s. Nice smooth and flat curve is best. Just some food for thought.

 

??? there are several people making around 400rwhp with 3" exhaust. Many have stepped up to 3.5, even 4 and not seen more than a 2-5hp gain. For what he has a good 3" is just fine.

 

I never understood why everyone thinks just because "This guy" makes "This power" with a 3 inch exhaust that those 3 inches somehow are the magical measurement. If you look on the exhaust board, you will find that a 3 inch exhaust was "JUST ENOUGH" for a slightly modified 3.4L V6. But I suppose since 3 inches is the sabbath number, that it should be "Enough" for an engine nearly twice it's size operating at similar speeds .... because you know, so-and-so made "X" power with it. Just because an engine is strong enough to make "Insert some number that impresses you" power despite a shortcoming (exhaust), doesn't meant that the shortcoming is good, or an ideal part of the system. Have those people tried anything else, and if so, where are the dyno charts to back up the claim of only 4 or 5 extra HP? There are a lot more McDonald's hamburgers out there than there are TGIFriday's burgers, but which is the better burger? (In other words, just because there are more 3 inch setups, doesn't make them better by virtue of number.)


Anyway - richen up the mixture, bump the timing, fix the exhaust.

https://www.thirdgen.org/forums/exhaust/300497-3in-exhaust-3-4-a.html?highlight=v6+3+inch
3 inch on a 3.4 made the same power as with the cutout open

https://www.thirdgen.org/forums/2503822-post21.html
Single 3 inch exhausts cost this guy 10 MPH with a 350

 

All hail GodOverYou!

Could not have said it better myself!