Horsepower, Torque. Borlas and such

[bronzebird]

Spent most of today at a local speed shop getting the exhaust system replaced, engine tuned and re-running dynamometer results.

First, I want to thank Julie, (Borla Babe) for helping me get the Borla system for Bronzebird and Bill, (Lone Star) for helping me get the exhaust tips I wanted. I have posted some pics of the tips that Bill has on his car and that are now on mine. I followed Bill's Cashmere at Choo Choo Thunder the day we went to Mount Vernon for lunch and fell in love with them. IMO the Borla tips are too overpowering and I stayed away from that system because I wanted something a little less noticeable.

When I had my car run on the dyno last month to check out horsepower and torque I was disappointed in the 237 HP and 232 Torque maximum numbers. The speed shop felt it was my Magna Flow system that was restrictive so I decided to change to the Borlas in view of the above.

Today we put the Borlas on (with the Corsa tips, Lone Star recommended) and ran it through the Dyno again. We iced the intake down after each of the three runs to get the maximum reading and I have attached the read out here. We got the same 237 HP maximum horsepower reading as before at about 5,600 rpm (124 mph in fourth gear) but the torque jumped up to 253. That is an increase of 21 foot/pounds with the Borlas (almost 10%). Horsepower is nice but it is torque that really turns the wheels.

I know that we have had folks on TBN tell us they got readings of 260 HP and I think I remember someone saying they got as high as 314. Based on what I have seen I just don't see that is possible without adding forced air (Turbo or Super) or Nitros Oxide. Bronzebird has a K & N cai, the Borla system and had brand new plugs installed today and could not get near those numbers.

Stock HP is 280. Figure a loss of 20% from drive train to rear wheels and the road HP would be 56 HP less, getting us to a net of 224. We figure my car is putting out 295 HP now and 237 at the rear wheels, so the performance stuff added 15 HP. Does anyone know what the stock Torque figures are?

There is a variance in dynos apparently but the one we used was calibrated for altitude and air pressure so we feel it is very, very accurate.

I'll post some pics of the installation showing the tips in another post.

Bronzebird

[Lonestar]

Re: Horsepower, Torque. Borlas and such

Looks great but I might be bias. The tips are just the right size for the rear of the Thunderbird. Not too big and not too small. Now, did they grind down the welds and polish?

I just wish I could have been able to get Corsa to make an entire system for our cars. Man, you think the tips are nice... their systems are incredible and are made to be true performance enhancing add ons.

The sounds of cat back systems are somewhat dictated by the engine they are attached to. Be that as it may, the systems they have had for the Mustang line up and now for the new Camaros are beautiful to look at and the sound is music to a car lovers ear.

[bronzebird]

Re: Horsepower, Torque. Borlas and such

Lonestar:

Here are some more pics. No, we did not grind down the welds and polish. I will probably do that myself some rainy day.

#1: looks good, sounds better... deeper tone than the Magna flows.
#2: Had to weld in a small extension.
#3: Close to maximum output @ 5,000 rpm in 3rd gear (110 mph).

By the way, while the car was in the air one of the techs at the shop noticed that there are hard rubber or composite connections at both the front and rear end of the driveshaft. He said that was a factory design in order to provide for smoother shifts but that because of that some power is lost while the shaft takes up the slack on the rubber.

He suggests putting in billet aluminum connectors front and rear. This will stop the loss of power during shifts and he feels it could cut the 1/4 mile time down by nearly a full second. I explained that not a lot of us run our Birds at the dragstrip but the comment was interesting in case anyone out there wants to get more positive shifts. Of course, you would feel it kick up and down.

Bronzebird

[Lonestar]

Re: Horsepower, Torque. Borlas and such

Stock torque & other info:

Engine Type
3.9L V-8 all aluminum

Valvetrain
4 valves per cylinder DOHC Bore/Stroke (in/mm) 3.39 x 3.35/86.1x85.0

Displacement (cu in/cc)
240/3934

Compression Ratio
10.75:1

Horsepower @ rpm (flywheel numbers)
280 @ 6,000

Torque (lb-ft) @ rpm (flywheel numbers)
286 @ 4,000

Redline
6,500

Recommended Fuel
91 octane (minimum)

Fuel System
Sequential multi port electronic fuel injection (SEFI)

[Lindy]

Re: Horsepower, Torque. Borlas and such

Lonestar:

By the way, while the car was in the air one of the techs at the shop noticed that there are hard rubber or composite connections at both the front and rear end of the driveshaft. He said that was a factory design in order to provide for smoother shifts but that because of that some power is lost while the shaft takes up the slack on the rubber. He suggests putting in billet aluminum connectors front and rear. This will stop the loss of power during shifts and he feels it could cut the 1/4 mile time down by nearly a full second.
Bronzebird

This is an interesting notion--can anyone out there authoratatively confirm this? If so, this would change many preconceptions of how or why our trannys shift.

--Lindy

[Lonestar]

Re: Horsepower, Torque. Borlas and such

The overwhelming majority of automatic transmissions are made to shift soft between gears and the connectors mentioned are to compliment that. An automatic trans guy can make an automatic literally bang between one gear and the next and although it is counterintuitive, that is actually better / easier on the transmission. However, you will get the feeling of basically popping the clutch in a manual transmission car between every shift. Changing the connectors mentioned from flexible to rigid material would have basically have a similar effect. Doing both would create quite a jolt between shifts. That is fine if you are racing but not real pleasant if going for a cruise.

The software tuner available (or use to be) for the 02-05 Thunderbird allow modification of shift points and in turn, harder shifts. This may be a better path to take if you looking for reduced ETs at the track.