[1funride]

Finally got the car over to the dyno. The engine build was a mild HFT 400, I was hoping for 400hp at the engine. This was simply a reality check and too have some fun. I only prepared by inflating tires to 40psi and changing the oil. Runs 1 and 5 are with the air cleaner, runs 2 thru 4 are without the air cleaner. The only change I made to the Fitech was to add more accelerator pump, which from the air fuel ratio is now to rich. We didnt mess with the timing, the dyno operator did tune the fitech some. There was a lean spot he tuned out. In general it ran a little fat. The cam seems a little small and the exhaust seems too restrictive, as I did not hit my 300hp at the wheel goal. I figured on a 25% loss, and only got 276 at the rear wheels, or around 368 at the engine. Engine was 194 degrees. There is a flex fan and power steering and alternator. The results were a little disappointing, but there is room for improvement.

https://www.youtube.com/watch?v=ikU_JI_7wMY

[1funride]

Another run

https://youtu.be/Wv1lxrjfXd4

[ponyakr]

Hey, the '69 RA3 engine had only 366hp & I loved mine. Ran mid 13's after 60K + street miles & a season & a half of drag racing.

Not sure why so many nowadays think they need 500-600hp, for street driven Pontiacs.

[moontower69]

Seems like a fun motor to me for "spirited" street driving - more than enough power to burn plenty of rubber. I personally think its more fun to push a stock motor and grunt it around the turns and use the laws of physics a little bit. Rather than these guys with their 500hp 455 motors that just roast the tires on demand - where's the challenge in that?

[1funride]

The engine feels strong than the numbers show. According to my 1/8th mile runs it should be high 12s in the quarter. Results of course that was a chassis dyno with 25% loss in driveline and with all the accessories and fan connected. I think they rated the old cars without any accessories.

[Lee]

My '03 Mach 1 put about the same HP and TQ numbers to the wheels, but weighed about 3460 with me in it. It ran 12.9's with Nitto DR's.

I think your exhaust is choking off 20+ hp and probably closer to 30 TQ,

[1funride]

I agree its time for a new exhaust any recommendations?

Its a 408 now with a mild HFT cam, cam will be changing to a roller in either the 408 or possibly a stroker. Would like an exhaust that can support the 408 and even up to a 467 if possible. A bolt in fit is always good.

Currently have doug's headers, plan on keeping those, and a flowmaster american thunder 2 chamber transverse cross flow muffler. The engine specs are 408ci, edelbrock D port 72cc, port matched to PP Crosswinds intake, water cross over cut to maintain port alignment, Ultradydne 274/282 226/233 .515/.515 w/1.65 H25/H18 Lobes LSA 112 ICL 107, MSD 6A, MSD Ready to Run, Fitech EFI, timing is 12 initial with 21 coming in at 1250 and full in at 2850.

[gtofreek]

I don't understand the whole 25% loss through the driveline thing. How can they rate that in a percentage? 25% of 300 HP is 75 HP. 25% of 1000 HP is 250 HP. You mean to tell me that a certain driveline will take 175 more HP to drive simply because the engine makes more HP? It just doesn't make sense. Seems to me the driveline will rob "X" amount of HP regardless of how much power the engine makes.

[Baron Von Zeppelin]

Sounds like it should be more in the 475hp range like the 408 with ported iron heads that gtofreek just built/dyno'ed .
It went through stock size R/A exhaust manifolds - no headers.
Just a wee little bit more cam - and a Qjet.

I would be PIZZED OFF .
Maybe that chassis dyno is REAL stingy

[dataway]

Originally Posted by gtofreek

I don't understand the whole 25% loss through the driveline thing. How can they rate that in a percentage? 25% of 300 HP is 75 HP. 25% of 1000 HP is 250 HP. You mean to tell me that a certain driveline will take 175 more HP to drive simply because the engine makes more HP? It just doesn't make sense. Seems to me the driveline will rob "X" amount of HP regardless of how much power the engine makes.

Yep, in the world of real life physics driveline loses will be relatively constant. Sure ... if you are sending twice as much HP through the driveline there may be an extra few HP in loses just because of greater friction loses under higher loads, but is it a straight percentage ... not even close.

With an engine of 350 crankshaft HP .... get 300+ at the rear wheels... I wouldn't be that disappointed. Either you are in the HP race or you are not, if you are building a street engine, throttle response and drivability mean way more than 30 hp on a dyno.

[1funride]

I was disappointed. I am trying to figure out where all my HP went?? Hahahaha. But seriously I was surprised, maybe even shocked. Good compression, good heads, port matched, ports aligned, the air fuel ratio is a little rich but overall it was good, timing I think is typical pontiac good (I am going to check that again), I degreed the cam, good spark, I expected more from the camshaft (with 1.65 rockers even) as it didn't make power past 5000 and we pushed it to 5700, Is it the exhaust is holding it back......and the cam does have a little more in it? Maybe the flex fan? Is it as simple as just an accumulation of drivetrain loss, flex fan, exhaust, and accessory loads?

Not that I am horsepower chasing, but when you have attention to detail and use parts that should perform a little better you want it to perform to its potential. As stated prior the car has very good throttle response and pulls through entire RPM range, easily breaks the Nitto tires loose when snapping the thrrottle in first gear half throttle driving speeds, spins them pretty good at 2nd gear shifts. The dyno runs shows it running smoothly with no hickups.

The TH400 is power hungry, I have read of real world tests where they take more than 25%, see article below for a real world test and the reality of big auto transmissions stealing your power.

https://www.hotrod.com/articles/ccrp...in-power-loss/

[Formulajones]

Originally Posted by ponyakr

Hey, the '69 RA3 engine had only 366hp & I loved mine. Ran mid 13's after 60K + street miles & a season & a half of drag racing.

Not sure why so many nowadays think they need 500-600hp, for street driven Pontiacs.

Because they want to keep up with everyone else

[Formulajones]

Originally Posted by gtofreek

I don't understand the whole 25% loss through the driveline thing. How can they rate that in a percentage? 25% of 300 HP is 75 HP. 25% of 1000 HP is 250 HP. You mean to tell me that a certain driveline will take 175 more HP to drive simply because the engine makes more HP? It just doesn't make sense. Seems to me the driveline will rob "X" amount of HP regardless of how much power the engine makes.

I'm in agreement, and have told people in the past trying to figure out flywheel numbers on a chassis dyno from a percentage is not that accurate. I've had an engine on the dyno, and the same car on the chassis dyno later. The percentage thing doesn't quite pan out.

[Formulajones]

Originally Posted by 1funride

I was disappointed. I am trying to figure out where all my HP went?? Hahahaha. But seriously I was surprised, maybe even shocked. Good compression, good heads, port matched, ports aligned, the air fuel ratio is a little rich but overall it was good, timing I think is typical pontiac good (I am going to check that again), I degreed the cam, good spark, I expected more from the camshaft (with 1.65 rockers even) as it didn't make power past 5000 and we pushed it to 5700, Is it the exhaust is holding it back......and the cam does have a little more in it? Maybe the flex fan? Is it as simple as just an accumulation of drivetrain loss, flex fan, exhaust, and accessory loads?

Not that I am horsepower chasing, but when you have attention to detail and use parts that should perform a little better you want it to perform to its potential. As stated prior the car has very good throttle response and pulls through entire RPM range, easily breaks the Nitto tires loose when snapping the thrrottle in first gear half throttle driving speeds, spins them pretty good at 2nd gear shifts. The dyno runs shows it running smoothly with no hickups.

The TH400 is power hungry, I have read of real world tests where they take more than 25%, see article below for a real world test and the reality of big auto transmissions stealing your power.

https://www.hotrod.com/articles/ccrp...in-power-loss/

Those numbers aren't terrible at all for a 400 Pontiac. When we were at a dyno day there were a handful of mild 400 Pontiacs that were under 300 RWHP. I remember 2 of them were in the same 275hp range you are, one was in the 280's. I was the only 400 that day that hit 301 RWHP and 355 RWTQ. There was even a hopped up 455 with open headers that barely did 320RWHP.
I was running through a 400 turbo with a stock converter, and a 12 bolt rear, all accessories including Alt, PS, Water Pump, Fuel pump, stock clutch engine driven fan, and the factory 70 RA air cleaner in place. All that stuff drags down HP. If you run even the slightest stall converter, it really sucks down the power at the wheels, which I suspect that 455 had, because his RWHP didn't reflect how he was running at the track that day (mid 11's)
If you run steel wheels, steel driveshaft, bigger rearends like 12 bolts, 9 inch, it will all suck the power down. So don't get too worked up over it. They are fantastic tuning tools though.

[Formulajones]

Originally Posted by 1funride

I agree its time for a new exhaust any recommendations?

Its a 408 now with a mild HFT cam, cam will be changing to a roller in either the 408 or possibly a stroker. Would like an exhaust that can support the 408 and even up to a 467 if possible. A bolt in fit is always good.

Currently have doug's headers, plan on keeping those, and a flowmaster american thunder 2 chamber transverse cross flow muffler. The engine specs are 408ci, edelbrock D port 72cc, port matched to PP Crosswinds intake, water cross over cut to maintain port alignment, Ultradydne 274/282 226/233 .515/.515 w/1.65 H25/H18 Lobes LSA 112 ICL 107, MSD 6A, MSD Ready to Run, Fitech EFI, timing is 12 initial with 21 coming in at 1250 and full in at 2850.

I don't believe your exhaust is holding you back. I ran that exact same exhaust system on my dyno run in my 70 formula that I mentioned above with it's stock 400.
Matter of fact, when racing the car, I started with the stock Gardener exhaust system. Upgrading to the Flowmaster 2 1/2" transverse system with H-pipe, and no other changes, didn't touch the engine, the car picked up a solid 5 tenths ET and went from 98-99 mph to over 102 mph consistently.
That's a solid 30 HP gain using the slide rule, with just the exhaust change to the Flowmaster transverse. This same car again, I later swapped over to the Pypes Transverse system, with X-pipe, still 2 1/2" system, because I couldn't help but wonder if the Flowmaster was hurting HP from all the stories you read. The car gained absolutely nothing. So at my power level with this car, it didn't care if it had the Flowmaster transverse or the Pypes transverse system on it.

It might come into play at bigger HP levels if you're pushing 500+ at the crank, but at our power levels, the muffler design and the X-pipe did nothing.

[mchell]

Originally Posted by 1funride

I was disappointed. I am trying to figure out where all my HP went?? Hahahaha. But seriously I was surprised, maybe even shocked. Good compression, good heads, port matched, ports aligned, the air fuel ratio is a little rich but overall it was good, timing I think is typical pontiac good (I am going to check that again), I degreed the cam, good spark, I expected more from the camshaft (with 1.65 rockers even) as it didn't make power past 5000 and we pushed it to 5700, Is it the exhaust is holding it back......and the cam does have a little more in it? Maybe the flex fan? Is it as simple as just an accumulation of drivetrain loss, flex fan, exhaust, and accessory loads?

Not that I am horsepower chasing, but when you have attention to detail and use parts that should perform a little better you want it to perform to its potential. As stated prior the car has very good throttle response and pulls through entire RPM range, easily breaks the Nitto tires loose when snapping the thrrottle in first gear half throttle driving speeds, spins them pretty good at 2nd gear shifts. The dyno runs shows it running smoothly with no hickups.

The TH400 is power hungry, I have read of real world tests where they take more than 25%, see article below for a real world test and the reality of big auto transmissions stealing your power.

https://www.hotrod.com/articles/ccrp...in-power-loss/

Don’t get too into trying to compare your numbers with “what others” are getting .....it’s a dyno.......every single one will produce a different number....best to get it to the track if you want to judge your real world power... the guess will turn into reality.....and frankly, that may be a disappointment as well....sound like a decent build, have fun with it

[gtofreek]

I built a 455 with 6X heads for a friend. The heads were ported, and it had a solid roller cam. That engine ran 10.90's @ 122-123 MPH in Phoenix[73 Firebird]. He had it chassis dynoed one summer in 100+ degree heat. It has a TH400 in it also. It dynoed at 485 HP to the rear wheels. If that car had a 25% drivetrain loss, then the engine would have been making 606 to the flywheel. There is no way that engine made 600 HP. 550 flywheel HP is more like it. That's about where it dynoed on our engine dyno. That's only about a 12% drivetrain loss by my calculations. So, based off these numbers, I get more like 304 rear wheel HP from yours.

[Lee]

Originally Posted by gtofreek

I don't understand the whole 25% loss through the driveline thing. How can they rate that in a percentage? 25% of 300 HP is 75 HP. 25% of 1000 HP is 250 HP. You mean to tell me that a certain driveline will take 175 more HP to drive simply because the engine makes more HP? It just doesn't make sense. Seems to me the driveline will rob "X" amount of HP regardless of how much power the engine makes.

TOTALLY correct. I've had a few rants on this previously. There are few people that have done more personal testing on chassis dynos than I have. I've seen 40+ hp differences JUST from changing torque converters. I've seen 35hp swings from air filter elements/housings.

The "25%" thing is horribly inaccurate. There are just TOO many variables.

[Steve C.]

And two interesting articles related to the subject.....

Dyno Thoughts and HP Losses

http://www.sdsefi.com/techdyno.htm


Comparing Chassis and Engine Dynos – Racing Dynos

https://www.hotrod.com/articles/1106...-engine-dynos/



.

[Lee]

Originally Posted by Formulajones

I don't believe your exhaust is holding you back. I ran that exact same exhaust system on my dyno run in my 70 formula that I mentioned above with it's stock 400.
Matter of fact, when racing the car, I started with the stock Gardener exhaust system. Upgrading to the Flowmaster 2 1/2" transverse system with H-pipe, and no other changes, didn't touch the engine, the car picked up a solid 5 tenths ET and went from 98-99 mph to over 102 mph consistently.
That's a solid 30 HP gain using the slide rule, with just the exhaust change to the Flowmaster transverse. This same car again, I later swapped over to the Pypes Transverse system, with X-pipe, still 2 1/2" system, because I couldn't help but wonder if the Flowmaster was hurting HP from all the stories you read. The car gained absolutely nothing. So at my power level with this car, it didn't care if it had the Flowmaster transverse or the Pypes transverse system on it.

It might come into play at bigger HP levels if you're pushing 500+ at the crank, but at our power levels, the muffler design and the X-pipe did nothing.

You went from one transverse system to a different transverse? What is the best ANYONE has ran with a transverse? Every time I've heard of somebody going from transverse to a quality true dual, they have gained performance.

I refer back to my testing earlier this year, documented at http://forums.maxperformanceinc.com/...d.php?t=814803
This was a very mild motor. Very low compression, mild cam, un-ported heads, Performer intake, Q-jet. HP peaked at just 4500rpm.

Yet a full 3" exhaust made a rather significant increase in both HP and TQ, I doubt my motor would break 350hp at the flywheel, yet the exhaust made a substantial difference in performance.

With a similar exhaust system to my own (and giving the EFI computer time to re-learn) I believe FunRide's car will gain AT LEAST 30rwhp, maybe closer to 50.