Wow!! Pretty good numbers. I would be very interested in what the numbers are on a chassis dyno. You hear so many different numbers of parasitic drag from drivetrain, auto vs manual and such. I wish somebody would take the same motor and do both back to back.
As firebob says, it would be interesting to see the same motor and what the drop in hp/tq would be. They say it can be anywhere from 15%-30%. If I ever install my 461 stroker/roller motor I have a free invite for a chassis dyno. I hope this comes to be as I would love to see what the ole Bird engine will pull...
Chassis numbers are usually a bit disappointing(to the owner anyway) because they just don't sound like enough hp. It's all pretty relative though. All setups are different but it would be nice to nail down some hard numbers on the drop though.
Chsssis dynos usually run from $50-$100 for 3 pulls with no tuning. A dyno tune session runs around $400-$500 around here. More if you're turboed or supercharged.
That's like all these new cars and their hp ratings, people don't always realize that they are advertising flywheel hp, not at the wheels. The new v6 Camaro sounds impressive at 303hp but when you are only putting 250 at most to the rear wheels, not bad for a v6 but certainly not a true 303hp.
The local Corvette club just had a big car show here in DeLand, FL. Any Vette to show up received 3 chassis dyno pulls for free. Let me tell you, there were some VERY upset Vette owners. To the point where a couple of them left the show and were ticked off at the guys running it claiming their Dyno was "off", broken etc.
They ran a ZR1 (supposed "625HP") and it pulled 470 at the rear wheels and the torque didn't even hit 500. So yes Dyno pulls can vary and most often leave the owners scratching their heads.
My 461 stroker as explained to me by my engine builder and Butler Performance is "guranteed" to put 425hp to the rear wheels and around 600lbs of torque on a chassis dyno. Hopefully I will be able to see this for myself unless of course I have to sell it off before firing it...
Well, there lies the problem. There is no "calculation". Basically there are two completely different types of Dynoes. One is with nothing but the engine on a stand and no other drive train components.
The other reads the HP at the rear wheels on a chassis dyno (where the entire car sits on the dyno). IMO the chassis dyno is where it's at. This tells you how efficiently and effectively your car is set up.
You could have a 1000hp engine but then drop it into a car that can't handle the HP and can not put those ponies to the rearend for squat. Kinda like the old saying, "where the rubber meets the road".
That's why typically they say whatever an engine can pull on the stand, deduct 15-30% for drivetrain loss etc. In the ones I've seen in person, it's usually the 30% figure that is most accurate...
Also, with both dynoes, the owner of the motor has to be willing to "risk" their engine and allow the dyno operator to MAX out the engine's RPM's. If you dyno an engine but only allow it to rev up to 4k RPM's then you are not going to get a true rating because your engine's peak may be at 6500 RPM's.
Your engine builder will always tell you your max RPM, this is where you need to push the engine and get your most accurate ratings.
I've seen guys pay $100 for 3 pulls but tell the operator not to exceed 4k RPM's etc. Well then you might as well keep your $100 and not waste anyone's time. Not too mention you are not going to be happy with the results!
Most Pontiac engines max out realatively low RPM's (5k-6k) whereas a BBC can go up to 7500 or more. My 461 stroker is rated at 5900 RPM's, when I had this motor in the Bird, it was done at no more than 5200 at MOST! But then again, Pontiac engines are known for low RPM and maximum torque. That's what I love about them!!!!!
I have been told over and over again, the biggest HP gain for the dollar is going roller. Roller motors put up the most HP with the least amount of effort. Hence the reason new cars are getting such impressive HP ratings yet lasting 200k miles. Going roller takes a TON of friction off the internals of a motor thus creating more HP.
Yes, it would be really interesting to see the numbers from a chassis dyno for comparison. But, unless I find a sponsor I don't think I'll spend the money on one. Since I'm not racing, I was more concerned about getting a proper break-in and making sure everything with the engine was go-to-go.
Johnny, I'm running 3.55 gears in the rear, so with 450 ft lb torque it definately has alot of pull
Gus, The engine dyno runs $85-$120 per hour x 8 hours.
Earlybird, My engine was taken to 5000 rpms. The dyno operator offered to take it highter, but we decided since I wouldn't run higher rpms and the engine had reached it's peak hp and torque there was no reason to go higher.
I wish I could get an engine dyno done for that. I'd dyno all my engines. Here it's a $500 flat fee so I use the chassis dyno, $75 min-$100hr or more depending on how long I'm on it.
My 365 cu in pulled 332 hp and 322 tq at the rear wheels, running lean. We pulled it to 6400 rpm. Peak HP was at 6200, tq was at 4900, not too bad for a little old Pontiac 350. Pretty sure we can break 350 RWHP fairly easy with some more tuning.
Wanting a Custom fit in an off the rack world.
I don't have time for a job, I just need the money.
A bit more detail; 451.6 ft lbs torque @ 3600 rpm 380.0 hp @ 4900 rpm
After putting in the 3.55 gears last year, I wasn't happy with the high rpm I was getting on the highway (TH350 trans).
I installed a 200R4 overdrive and it seems like the perfect fit for the driving I want to do. The 200R4 bolts right in and I picked up a shifter kit from Shift Works. The kit includes the detent and plastic plate for the console. The console still looks stock. The plastic plate (including OD) replaces the stock one.
...still a good 1st gear ratio (actually slightly better than the TH350) and the option of clicking it into overdrive on the highway. I'm running about 2200 rpms at 65-70 mph.
Another quick note on Trevor's engine; the torque peak was below the start rpm of 3500, likely about 3000 rpm and higher than the number quoted. As he said, the session was more about break-in and sorting out than ultimate output.
I have been told over and over again, the biggest HP gain for the dollar is going roller. Roller motors put up the most HP with the least amount of effort. Hence the reason new cars are getting such impressive HP ratings yet lasting 200k miles. Going roller takes a TON of friction off the internals of a motor thus creating more HP.
Not to mention that rollers can have a much more aggressive and efficient profile to open and close the valves a lot faster than a flat tappet cam. The technology of today's grinds are way ahead of those just a decade ago. I think that is were the most gain in HP is from.
Spidey, can you offer a little more info regarding your tranny swap? I sure do like the sound of 2200RPM at 65mph!...thats about 800rpm or so lower than I'm running with my TH400 and 3:55's
I'm a hobbyist. Not a professional. Don't be hatin'!
Sure Bronze Bird. Once I changed my rear ratio to 3.55 with the TH350, I was running about 3300 rpm on the highway at around 70 mph. (these numbers might be out a little, but I think they're close)
I like taking my Bird on the highway as well as running around the streets. I'm not racing it, so I didn't have to take those factors into consideration.
The 200R4 offers the best of both worlds, in my opinion. Good (actually better) 1st gear ratio, yet an overdrive ratio for highway driving. ------TH350----200R4 1st---2.52-----2.74 2nd---1.52-----1.57 3rd---1.00-----1.00 OD--------------0.67
From what I understand, the 200R4 wasn't a real strong transmission back in the day, but there are a lot of updates they have developed over the years. If you check out the websites of the guys selling them, they go into detail about the improvements.
Thers's a bunch of guys selling the 200R4 (TCI, Bowtie, Art Carr, etc) that all have the updates done to them.
I bought mine from Gear Star (http://www.gearstar.net/about/). It came complete with trans, torque converter, TV cable, dipstick, synthetic oil). Basically, everything you would need for the installation.
I also picked up a shifter conversion kit from Shift Works (http://www.shiftworks.com/firebird.htm#6869firebird). This kit includes the detent plate, linkage bracket and console selector plate. When you're done, the console still looks original.
I'm now running about 2200 rpms at 65-70 mph. So it's really good on the highway. With the low 1st gear ratio (and 450 ft lbs of torque ) it has lots of get up & go for me.
The TV cable was a little tricky to get set up correctly and I find it's easier to leave the transmission in 3rd around town, shifting it manually into OD when required. Otherwise with the transmission in OD around town, it seems to "search" for the right gear shifting back and forth between 3rd and OD.
Overall, I'm really happy with the results of this installation.
If there's anything else you're wondering about, just let me know. I'd be happy to post whatever I can. Trevor
.67 is one hell of an OD, I can see why it would hunt around town. But a perfect set up for highway use. The manual shift into OD wouldn't be much of a problem. 2.74 and a 3.55 should get off the line pretty good as well.
I run all straight drives but Autogear now offers an M-21 with 2.19 first and .86 4th, might have to investigate that for use in my 4.11 rear car.
Wanting a Custom fit in an off the rack world.
I don't have time for a job, I just need the money.
Appearently they have indeed made some progress with the 200R4. My friend just installed one behind a 500hp Butler 455. However, he did ruin something inside his first 200R4 due to the TV cable not being installed properly. The shop did warranty it though and rebuilt it. It is now back in the car and running VERY strong! This shop that is building them is located in Tampa, FL and supposedly build one of the best 200R4 on the market right now.
Ya, I know the TV cable hook up and adjustment is critical. It's good they stood behind it and covered the problem!
I know a lot of companies offering the 200R4 have different levels of rebuilds they offer, based on HP. The higher the HP requirement, the more / better updates.
What heads are you running? Are they stock of modified? Did you do anything to lower the static CR?
I ask because I'm still getting ready for an engine rebuild in the near future and trying to make some decisions. It looks like you've hit the same amount of power that I'm aiming for.
#16 heads, street ported, L2262F pistons machined for a 15 cc dish to get 9.6:1 compression. No problem running 91 octane but keep in mind that the ADR (Absolute Density Ratio) on the test day was about 82.
So those pistons are generally for 400. They would be .120 over in the 350. Both motors run the same stroke crank. You're using 400 heads. So what makes it a 365 instead of 400?
Uh, sorry about that. I was curious about ho428's 365 motor. He said he has 2262s and I thought I remembered them as the same number pistons that I put in my 400 last time. Only thing I can think of is if it's been destroked. Just curious. Didn't mean to thread steal.
Hey Mike, Are we talking about the 200R4? No core charge. I think it was about $1700 + $400 shipping, but I could check back in my receipts to let you know for sure. Gear Star's current pricing is on their website. (http://www.gearstar.net/about/).
Yes, included torque converter, trans oil cooler, dipstick, synthetic oil, tv cable... pretty much everything except the shifter parts. These I got from Shift Works. Trevor
