Dyno results alittle dissapointing

795.0pacecar

lover of pudgy polygamists
Jul 11, 2003
480
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17
Senoia, GA
My baseline with BBK headers, off road h-pipe, magnaflow catback, cai, timing at 15 degrees, and the smoge equipment deleted was 220.5rwhp at 4700 rpms and 285.1rwtq at 3600 rpms.

After installing thumper heads, 1.7RRs, new lifters, TFS track heat intake manifold, 65mm tb, timing set back at 9-10 degrees, and an accel FPR, my car put down 248.7 rwhp at 5300 rpms and 287.2 rwtq at 4200 rpms. I think it should be making around 20 rwhp more than that based on what I've seen very similar combos put down. I know its over intaked but I got a real good deal on that intake and all the bigger intake should be doing is shifting the power band to the upper rpms. The fuel pressure was at 41psi with the vacuum line off.

The dyno operator says I could see 20-30 more rwhp by getting a tune but thats $500.
Im thinking about dropping the fuel pressure to 39psi and advancing the timing to 15 degrees. Im also going to check the plugs. I think its probably running way rich. Keep in mind this is a speed density car and both pulls were done on the same dyno.

Any insite would be greatly appriciated.
 
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There's no point in shifting the power in the the RPM when the cam won't go there. I think I've read a zillions times here on Stangnet that the cam is done by about 5,000 RPM. I have seen dyno sheets where the bigger manifolds didn't outperform the stock manifold until close to the stock cam's upper rev range.

Did you have Thumper port match the manifold to the heads or was it just a bolt on affair? If the ports on the heads are smaller than those of the manifold the air will be running into a brick wall and slowing down velocity.

There was a thread recently about the benefits of 1.7 rr over 1.6 and it seemed to be a hit or miss situation. Some people got more power, some lost and some saw no difference.

These three things alone could easily account for your lack of expected power. Add in your pulling of 5 to 6 degrees of timing and it's no wonder you didn't see what you expected.
 
actually thats in the ball park......a few degree's of timing can make a big diff, i bet it that was bumped back up youd be in the 250's maybe 260.....plus, maybe that track heat isn't as well suited.......as some other manifolds might be.....what are you using for a maf?? i ask as i didn't see a larger than stock one listed.....anyway, with the timing set down, maybe a few hp diff depending on the manifold and just other natural variables, your about in that 250 ish to 270 that combo usually runs i think....

hp numbers aside, how does it run?? does it feel alot stronger than a 30 hp gain??
 
mustangGT85 said:
he doesnt have a MAF its speed density

oh duh.....i missed that:bang:
is he at that point with mods where the sd would start to have a negative effect???
oh and 795.0pacecar, i'd posted this a couple days ago, t moss posted it again, incase you didn't see it, this chart may make you feel a little better about the numbers....there's a couple on here listed that are speed density too....
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I told thumper I was going to be using the track heat, I dont know if he port matched them or not, but looking down the intake port, they looked pretty flush. I know the intake is too much, I have bigger plans later on down the road and I got a good deal on this so I went with it. I dont see any reason to go to mass air. At full throttle no matter if its SD or MAF the comp is dumping fule in it at its maximum programed duty cycle and fuel pressure, it also runs just fine with the speed density it just seems o be running alittle rich.

It does feel alot faster though. I would spin through first and bark 2nd before, now it spins all the way through the begining of third and barks 4th. It actually feels faster than my dads 03 mach 1 which dynoed 287hp and 305tq and has 4.10 gears.

Im going to bump the timing back up to 15 degrees, drive it for a while, then check the spark plugs to determin wether or not it would be wise to take a couple psi out of the fuel pressure. I would just like to see around 260 rwhp.

Do you guys think a tune would be a good idea. I plan on keeping it speed density because my car is a 79, so the battery is on the passengers side so the CAI is actually realy short and the filter is in the fender well right after the starter solenoid which is also on the passengers side. The drivers side has the coolant overflow/windshild wiper fluid bottle where the battery would be on an 86+. So swapping sides with the battery is kind of not an option and Im not sure I would have enough room to fit a MAF sensor.

Heres a pic of my dirty ass engine bay to give you guys an idea of what Im talking about.
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your mods will work fine with SD. I ran thumpers heads with tmoss ported stock lower 24# injs comp cams nx264hr cam then swapped to a cobra intake and it ran great! I eventually swapped to maf just to see and it ran about the same. Maf brought more tuning issues with it. SD is easy to tune if you know what to do with it. You dont need a 500.00 tune. Just play with the timing and fuel press until you find a happy medium. I tweeked with my set up on my own and when I finally put it on the dyno We played with timing and fuel. Turned out I had it set exactly where it needed to be.

Dont get caught up with the dyno numbers. Take it to the track and get some runs on it. Compare them to your original before swap runs. Heres what I found. Before the swap my 87vert ran 15.50's @ 85-90 after the swap it ran a best of 13.90 @ 100 all on street tires and at full weight apprx 3800# with driver. no weight reduction.On stock bottom end with 130k on it. Those are true numbers and thats a nice gain for the amount invested.
 
put your timing back at 14 or so and get an electric fan, you'll get your 260 i'm sure........
like i said if you look at those numbers in the chart your right on, plus or minus some....
you may wanna wait for a tune if your going to be doing alot of stuff down the road......unless you have the extra money to spend.....although i don't think there's much more you can do to it without switching to maf.....you can maybe put a maf in the fender well....depending on your set up.....but you probably don't need it right now
 
BTW I would suggest 14 degrees and 40 psi with out vac. would be a good starting point.

I agree that an Electric fan is a good idea. Lets the motor rev faster as well as free up HP. Makes a very noticable differnce.
 
I put the timing at 14, I'll drop the fuel pressure to 40 tomorrow after I check the plugs. I was thinking about getting electric fans, they are just kind of expensive. If I found some cheap I would get them. Do the clutch fans realy rob that much power? I can turn mine with very little resistance untill it warms up. Would I need an alternator upgrade? I have a new stock replacement and Im not runing any wild sterio equipment or anything.

I'll take it to the track as soon as it opens. You guys are right that the track is where it realy counts. Last time I went to the track was about 3 years ago. Everything was stock 88 mustang stuff, the only performance upgrade was a crappy dynomax catback. It still had 2.73 gears and 27" tall tires and an AOD and I ran a 15.0 at 93mph.
 
The sn95 fans can be had rather inexpensive but they do pull some serious amps when ran on the HI side, The low side will cool just fine and pulls less amps. I have the Black magic fan it seems to work just fine but its expensive. YOu will want a 2500-3000 cfm fan in order for it to work well.
yes the mechanical fans rob power and create DRAG on the motor. and also wear out the water pump bearing faster.
 
Do you have scans of both dyno sheets?

In my opinion peak numbers aren't as important as the area under the curve. take a look at the two sheets and see if the torque and horsepower curves flattened out and have more area under them when compared to the old dyno.
 
the clutch fan can rob alot if its going out on you , put a new one on it whether you need it or not because they lose about 100-200 rpms every 15K miles is what I have heard before just from normal driving , until they start locking up .......put the fuel pressure back to 38 and bump the timing to 14 and I would say it will hit the 260 mark no problem ....
 
The clutch has no more than 10-15k miles on it and if Im going to upgrade to an electric sometime soon there no need to change it. I put the fuel pressure at 40 psi, it was actually at 42 before, it feels alot better throughout the rpms. Im going to drive it like this alittle then check the spark plugs and adjust the pressure some more.
 
id suggest 18 degrees.. or 17 atleast.. its where my car runs the best and seems to make the best power and a tauros fan will work wonders for your car
 
In order to check the plugs as in to tell if ur running rich or lean at WOT u need to shut it down right away after a WOT run, im not saying it pull over on the side of the road to check them but u cant do a WOT run and then drive around or let it idle in ur driveway or something and expect to see how its running at WOT, ya know.
 
Well WOT doesn't realy concern me too much, its just cruising around part throttle that bothers me since the computer relys on the fuel tables which cant possibly be able to support the power Im making now.