"Dragon" Plenum Dyno results.................

TacBear

Founding Member
Dec 28, 2001
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Jasper, AL
This is a before and after Dyno of my car. The only change was a "Dragon" Plenum and a Magnaflow catted "X" pipe.

Before-229 rwhp and 279.5 rwtq

After--241.4 rwhp and 289.1 rwtq

Gained--12.4 rwhp and 9.6 rwtq.

Catted "X"s are usually worth 4-5 rwhp and 4-5 rwtq, so I figure the "Dragon" was worth about 8.4 rwhp and 5.6 rwtq. I can live with that.
 
TacBear said:
This is a before and after Dyno of my car. The only change was a "Dragon" Plenum and a Magnaflow catted "X" pipe.

Before-229 rwhp and 279.5 rwtq

After--241.4 rwhp and 289.1 rwtq

Gained--12. rwhp and 9.6 rwtq.

Catted "X"s are usually worth 4-5 rwhp and 4-5 rwtq, so I figure the "Dragon" was worth about 8.4 rwhp and 5.6 rwtq. I can live with that.

I think the catted X gave you 8-10 rwhp and the plenum only gave you 2-4 rwhp. Either way you've gained some good horse and torque! :cheers:
 
JOHNS01GT said:
I think the catted X gave you 8-10 rwhp and the plenum only gave you 2-4 rwhp. Either way you've gained some good horse and torque! :cheers:


I will never know for sure, but I have seen plenty of before and after dyno's on "Catted" X pipes that only showed a small gain (4 to 5 hp)!
 
We can't really say what gave more power. Every car is different and plus the dynos were taken on different days i'm assuming so lets just look at the results and say they were good gains.



















that being said. Go Dragon! :nice:
 
wms004 said:
We can't really say what gave more power. Every car is different and plus the dynos were taken on different days i'm assuming so lets just look at the results and say they were good gains.

that being said. Go Dragon! :nice:

In MM&FF, they tested the C&L plenum.. I think it's the same piece your talking about (costs $189) and they gained 10HP@5200RPM just from that mod. With the Accufab Throttle Body, they gained like 2.2 HP but at a higher RPM of 5500 :banana: . Pretty good results though from a relatively cheap mod.
 
Dark Knight GT said:
Although its already been said, I too agree that the mid-pipe is giving you probably at least 7-8rwhp. The rest was probably the plenum.

All of the tests on C&L's web site they were done with STD dyno numbers and on cars with heavy bolt-on's.

Direct quote from C&L's web site: "Realistically, the installation of this plenum and 75mm throttle body on very mildly modified vehicles will add at least 8 rear wheel horsepower, and it is possible to receive as much as 11-15 rear wheel horsepower and up to 20 ft/lb of torque on more heavily modified vehicles with a good combination of bolt-ons."

For whatever reason, they didn't bother to test their product on any "mildly modified vehicles" which leads me to believe the gains are marginal, if any on a basically stock GT - probably due to the stock h pipe!

If you recall the plenum test done on modulardepot.com, the test vehicle was breathing very well (i.e. LT's, o/r pipe, CB). Do to the nature of the plenum mod. (more airflow), it's going to respond better on a car with a low restriction exhaust system.
 
TacBear said:
This is a before and after Dyno of my car. The only change was a "Dragon" Plenum and a Magnaflow catted "X" pipe.

Before-229 rwhp and 279.5 rwtq

After--241.4 rwhp and 289.1 rwtq

Gained--12.4 rwhp and 9.6 rwtq.

Catted "X"s are usually worth 4-5 rwhp and 4-5 rwtq, so I figure the "Dragon" was worth about 8.4 rwhp and 5.6 rwtq. I can live with that.
dude, i think you are kinda backwards with your gains.
 
2000GT said:
All of the tests on C&L's web site they were done with STD dyno numbers and on cars with heavy bolt-on's.

Direct quote from C&L's web site: "Realistically, the installation of this plenum and 75mm throttle body on very mildly modified vehicles will add at least 8 rear wheel horsepower, and it is possible to receive as much as 11-15 rear wheel horsepower and up to 20 ft/lb of torque on more heavily modified vehicles with a good combination of bolt-ons."

For whatever reason, they didn't bother to test their product on any "mildly modified vehicles" which leads me to believe the gains are marginal, if any on a basically stock GT - probably due to the stock h pipe!

If you recall the plenum test done on modulardepot.com, the test vehicle was breathing very well (i.e. LT's, o/r pipe, CB). Do to the nature of the plenum mod. (more airflow), it's going to respond better on a car with a low restriction exhaust system.

I dont know if I would be quick to believe what C&L posts on their site. Afterall, it follows logic thought that C&L would only choose the best dyno gains for display on their site.

Although you open up the intake flow, you have to remember something. The key to power in theese cars isnt just a big flowing intake. Its in the displacement, cylinder heads, and cams. If you still have the stock displacement, cams, and heads, youre only going to flow so much air to the engine. Even the bullit intake(a very nice piece) only yields on average of 5 or 6rwhp gain across the powerband on stock internal 4.6ltr motors. This is naturally due to the restriction of air flow ofthe stock heads and cams as well as the smaller displacement of the motor the 4.6ltr is noted for.

I agree though with the assumption of "Higher flowing exhuast + higher flowing intake = best power gains". Either way, the gains of 12.4 rwhp were reported here. I just think from my experience with seeing dyno sheets, the gains would more likely be contributed to the exhuast mods as vs. the intake mods.
 
Dark Knight GT said:
I dont know if I would be quick to believe what C&L posts on their site. Afterall, it follows logic thought that C&L would only choose the best dyno gains for display on their site.

Although you open up the intake flow, you have to remember something. The key to power in theese cars isnt just a big flowing intake. Its in the displacement, cylinder heads, and cams. If you still have the stock displacement, cams, and heads, youre only going to flow so much air to the engine. Even the bullit intake(a very nice piece) only yields on average of 5 or 6rwhp gain across the powerband on stock internal 4.6ltr motors. This is naturally due to the restriction of air flow ofthe stock heads and cams as well as the smaller displacement of the motor the 4.6ltr is noted for.

I agree though with the assumption of "Higher flowing exhuast + higher flowing intake = best power gains". Either way, the gains of 12.4 rwhp were reported here. I just think from my experience with seeing dyno sheets, the gains would more likely be contributed to the exhuast mods as vs. the intake mods.

Yup, that's my point. Why didn't C&L test their plenum on a stock GT? You know the gains would be poor and thus, they wouldn't sell as many plenums. Instead they chose highly modified cars to run their tests.

I have to admit that I am on the fence still as to if the plenum really adds any more power. Like you said, the engine is only capable of so much volume staying N/A. I don't see how a plenum is going to add any more volume of air because it's not like it's going to compress the air such as a blower does.
 
I almost wonder if the plenum/TB combo maybe just helps to broaden the hp & tq curve, providing bigger gains over stock at areas under the peaks. The reason I am speculating is that I honest-to-god felt this modification. The real test for me will be this spring when I hit the strip. If I run significantly over 100 mph, then I'd say the plenum/TB helped.

Maybe the TB/Plenum even just helps more at part-throttle instead of WOT??
 
BMan5150 said:
I almost wonder if the plenum/TB combo maybe just helps to broaden the hp & tq curve, providing bigger gains over stock at areas under the peaks. The reason I am speculating is that I honest-to-god felt this modification. The real test for me will be this spring when I hit the strip. If I run significantly over 100 mph, then I'd say the plenum/TB helped.

Maybe the TB/Plenum even just helps more at part-throttle instead of WOT??
I'd say the entire curve was effected..
TBCompareTest2.jpg

taken from C&L

-wade