For those of you who remember me installing the all coveted Roush 3-piece intake (http://forums.stangnet.com/showthread.php?t=483948), you may recall that I planned on getting a dyno done afterwards to see exactly how much I was gaining. Well, life got in the way and I didn't get around to it until today. Now before I get into the results, let me go over some of the background to give you a better idea of exactly what you're looking at here.
Prior to installing the intake, the car dyno'd to 232 hp, 304 tq.
These are SAE corrected numbers, read on a Dynojet on 13 June, 2004. Mods included a Bassani offroad X-pipe and catback, ASP pullies, the accessories bypassed, and that's about it. I was extremely happy with the numbers and many people (here and elsewhere) were impressed with the numbers considering the relatively few modifications.
Well, one of the beauties of using the same dynometer is that they can look over your previous runs. This happened today. This is when we found out that my last runs didn’t have the pressure calibrated properly. Well screw me running. So the last SAE corrected numbers are erroneous. False. Complete and utter BS. DANG it! So taking out the SAE correction for the last runs, it turns out that I made 205 hp and 269 tq.
This wouldn’t be too big a deal if the runs were a week or so apart. Unfortunately, they were 6 months apart. So now the entire plan of getting dyno numbers to document the intake swap is screwed up. The weather coupled with lack of accurate SAE correction means these numbers are all subjective.
So anyways, after the last dyno, I installed the Roush intake. The intake actually came as a kit and includes 24# injectors, 65mm TB, and a whole slew of other items required to make it all work properly. See the thread referenced above for the complete list. My goal was to get dyno numbers before and after, while changing nothing but what was included in the kit. However, I did install an adjustable fuel pressure regulator and gauge in addition to everything. I left the pressure set at a stock setting however and installed them more for tuning after the fact than anything else. I also left the timing set to where it was before (6* initial) even though I feel I can safely dial more in at this time. This car has had a history of detonation with higher timing, even with the 93 octane I routinely run. Aside from what I just mentioned, I also had to replace the harmonic balancer and distributor since the last dyno, but I don't see any appreciable change from that. The distributor is a stock replacement and the balancer is an FMS SFI unit. While a rebuilt dist. might make the timing more accurate, I don't see an appreciable gain from this change, certainly no more than 1-2 hp.
The only difference that I feel will affect performance is time. I'm still running the same plugs, wires, cap, and rotor as I was before. Obviously, the 6 months that they've been wearing down will affect the performance, but if anything, it will degrade, not improve the numbers.
So enough of the blah blah blah, right? You want the numbers? Alright, fine. Blue is the baseline and red is with the Roush intake.
I have mixed emotions about the results. On one hand, power stayed pretty much the same until about 4k. That’s when it continued to climb until 5k, where we stopped the run. Peak torque numbers are down a couple points but the curve is still very flat and is much higher than before after 4k. Had I continued the run out to 5500 rpm, I’m sure the power would have climbed a bit high. The charts tell me that the intake is performing better than stock and now the stock heads and cam are the bottle neck.
However, Roush advertised 47 hp to the crank with this setup. Figuring in 16% drivetrain loss, that’s only 36 hp. Now I know that the car needs a tune up. The plugs and wires are older than snot (2.75 years) and the dyno operator said that the clutch felt like it was slipping a little. This might make up for the loss but I can’t say for sure. I do know that I will be doing a full tune-up on it and taking it back because I’m not satisfied with it right now.
Unfortunately though, there will be one more change to the setup during the next run. While strapping the car down, the operator noticed that my U-joints are getting pretty bad. I haven’t noticed because 99% of all my suspension is solid links. Vibration is a everyday thing. So before going back, I’ll be installing the T56 with the new driveshaft. This does nothing to affect the power of the motor, but due to current dyno designs, it might read a difference due to the change in the moment of inertia. It’s true that I have extra mass in the tranny, but an aluminum flywheel and driveshaft are being installed to counteract this. I believe I’ll see a net loss of MOI, and the dyno will read this as a power output increase.
So now I’m sitting at home, drinking a beer. It isn’t a victory beer, but I’m not crying in it either. Like I said, mixed emotions. Considering the dyno numbers up high, I know the intake will perform given a good combo. I just can’t say that it’s good for a stockish motor yet. After the next dyno, I’ll feel better about giving some opinions on the matter.
Prior to installing the intake, the car dyno'd to 232 hp, 304 tq.
These are SAE corrected numbers, read on a Dynojet on 13 June, 2004. Mods included a Bassani offroad X-pipe and catback, ASP pullies, the accessories bypassed, and that's about it. I was extremely happy with the numbers and many people (here and elsewhere) were impressed with the numbers considering the relatively few modifications.
Well, one of the beauties of using the same dynometer is that they can look over your previous runs. This happened today. This is when we found out that my last runs didn’t have the pressure calibrated properly. Well screw me running. So the last SAE corrected numbers are erroneous. False. Complete and utter BS. DANG it! So taking out the SAE correction for the last runs, it turns out that I made 205 hp and 269 tq.
This wouldn’t be too big a deal if the runs were a week or so apart. Unfortunately, they were 6 months apart. So now the entire plan of getting dyno numbers to document the intake swap is screwed up. The weather coupled with lack of accurate SAE correction means these numbers are all subjective.
So anyways, after the last dyno, I installed the Roush intake. The intake actually came as a kit and includes 24# injectors, 65mm TB, and a whole slew of other items required to make it all work properly. See the thread referenced above for the complete list. My goal was to get dyno numbers before and after, while changing nothing but what was included in the kit. However, I did install an adjustable fuel pressure regulator and gauge in addition to everything. I left the pressure set at a stock setting however and installed them more for tuning after the fact than anything else. I also left the timing set to where it was before (6* initial) even though I feel I can safely dial more in at this time. This car has had a history of detonation with higher timing, even with the 93 octane I routinely run. Aside from what I just mentioned, I also had to replace the harmonic balancer and distributor since the last dyno, but I don't see any appreciable change from that. The distributor is a stock replacement and the balancer is an FMS SFI unit. While a rebuilt dist. might make the timing more accurate, I don't see an appreciable gain from this change, certainly no more than 1-2 hp.
The only difference that I feel will affect performance is time. I'm still running the same plugs, wires, cap, and rotor as I was before. Obviously, the 6 months that they've been wearing down will affect the performance, but if anything, it will degrade, not improve the numbers.
So enough of the blah blah blah, right? You want the numbers? Alright, fine. Blue is the baseline and red is with the Roush intake.
I have mixed emotions about the results. On one hand, power stayed pretty much the same until about 4k. That’s when it continued to climb until 5k, where we stopped the run. Peak torque numbers are down a couple points but the curve is still very flat and is much higher than before after 4k. Had I continued the run out to 5500 rpm, I’m sure the power would have climbed a bit high. The charts tell me that the intake is performing better than stock and now the stock heads and cam are the bottle neck.
However, Roush advertised 47 hp to the crank with this setup. Figuring in 16% drivetrain loss, that’s only 36 hp. Now I know that the car needs a tune up. The plugs and wires are older than snot (2.75 years) and the dyno operator said that the clutch felt like it was slipping a little. This might make up for the loss but I can’t say for sure. I do know that I will be doing a full tune-up on it and taking it back because I’m not satisfied with it right now.
Unfortunately though, there will be one more change to the setup during the next run. While strapping the car down, the operator noticed that my U-joints are getting pretty bad. I haven’t noticed because 99% of all my suspension is solid links. Vibration is a everyday thing. So before going back, I’ll be installing the T56 with the new driveshaft. This does nothing to affect the power of the motor, but due to current dyno designs, it might read a difference due to the change in the moment of inertia. It’s true that I have extra mass in the tranny, but an aluminum flywheel and driveshaft are being installed to counteract this. I believe I’ll see a net loss of MOI, and the dyno will read this as a power output increase.
So now I’m sitting at home, drinking a beer. It isn’t a victory beer, but I’m not crying in it either. Like I said, mixed emotions. Considering the dyno numbers up high, I know the intake will perform given a good combo. I just can’t say that it’s good for a stockish motor yet. After the next dyno, I’ll feel better about giving some opinions on the matter.
