(now more of why my car cant 60) Shift Point.HP or TQ peak??

[Bowtiestang]

I am not sure if it was a fluke or what but here is the story..

I shift at 7000rpm most of the time..well last time at the track I was doing the same (7000 rpm shifts) and the car was running the norm 11.38+-.
Well on one run I brain fart and shift at 5500+- on the 1-2 shift well I figure this run is screwed so I shift 2-3 at 5500+- and get this it runs a 11.20???
This is near the end of the night so I hurry and chang the shift light to 6000 for the hell of it and do another run to try.....the clocks screw up and I GET NO TIME

So I look up the only dyno info I have.....desktop dyno and here is my peaks

HP= 554@7000 rpm
TQ=479@5500rpm

So should one shift @ peak TQ or HP?? Boy the run I shifted at 6000 felt really good but I got no time... but a small block 355 with soild roller and 210 cc heads shifting under 6000 rpm

WHAT SAY YOU???

[supernova]

First off I would not trust the desktop dyno as the last word. (REFERENCE ONLY) I have the high dollar one.

You may be over reving the motor right out of the power band and loosing time not knowing it.

You have stumbled on to something so do some testing on lounch and shift pionts to find what work best for your combo. Your motor may like the lower rpm range and thats not a bad thing. Parts live longer at lower rpm's.

[Bowtiestang]

I hear that alot about desk top dyno but I swear by it...if you put good info it is damn close. On my car I call the airport weather to get the temp and DA plug it in and it has never been off by more then .1 sec or 1 mph

here is one of my runs and what dyno guessed... it will do this 10 out of 10 times. BUT if I change the shift points down to 5500 or 6000 dyno will slow the car down to 11.50 or so.

Guess I need to go play with shift points some

Real run..
60 330 1/8 MPH 1000 1/4 MPH
1.657 4.743 7.290 96.53 9.488 11.347 121.08

[Bowtiestang]

Here is a copy of the dyno file.... I cant wait to race again to play with this again!

[Hitchcock]

I am not sure if it was a fluke or what but here is the story..

I shift at 7000rpm most of the time..well last time at the track I was doing the same (7000 rpm shifts) and the car was running the norm 11.38+-.
Well on one run I brain fart and shift at 5500+- on the 1-2 shift well I figure this run is screwed so I shift 2-3 at 5500+- and get this it runs a 11.20???
This is near the end of the night so I hurry and chang the shift light to 6000 for the hell of it and do another run to try.....the clocks screw up and I GET NO TIME

So I look up the only dyno info I have.....desktop dyno and here is my peaks

HP= 554@7000 rpm
TQ=479@5500rpm

So should one shift @ peak TQ or HP?? Boy the run I shifted at 6000 felt really good but I got no time... but a small block 355 with soild roller and 210 cc heads shifting under 6000 rpm

WHAT SAY YOU???

I have heard on another forum from a builder named joe Sherman that on a 3 speed trans. Short shifting the 1-2 shift and over revving the 2-3 will always pick up et. Some peolpe on that site went out and did it and everyone said they ran quicker.

[Hitchcock]

Here is a copy of the dyno file.... I cant wait to race again to play with this again!

How did you copy that and get it here?

[Bowtiestang]

Here is a copy of the dyno file.... I cant wait to race again to play with this again!


How did you copy that and get it here?

First open dyno and press the Ctrl and print screen keys.
Now open paint and hit Ctrl and V keys...thyis will paste the pic.
Now upload it to photobucket or the like and link it as a image.

[572 BBC]

its air fuel problem or valvetrain in my opinion...either valvesprings uncontroling valves or maybe look at fuel system and include carb on that one

[Bowtiestang]

its air fuel problem or valvetrain in my opinion...either valvesprings uncontroling valves or maybe look at fuel system and include carb on that one

Dont think its either.. I run with a wide band O2 and at WOT its around 12.5-12.8 so I think that is cool. My springs are new this year and good for .700 lift. I have run the engine up tp 7500 with no float...at least I dont think the thing is crisp from start to finsh..

This isnt a great video but maybe you guy can see or hear something I dont .... Remember this is only a 355ci in a 3000lbs car in the high desert 80-100deg and a DA around 5000-6000 feet. I dont think it would run low 11s with valve or fuel issues.

[BracketNova]

I posted a similar question a few weeks ago. My car like the rpm drop to fall down on its desktop dyno peak torque. I was shifting at 6000 but I gained .03 moving it to 5800. 5400 added .04 to the original time. My glide exibits a 800 rpm drop so my 5800 shift drops to 5000 where my peak torque is. That's my experience.

Greg

[sc racing]

I wouldnt even consider the info on the desktop dyno, Have you ever seen a real dyno sheet on an enige will make 40-50 hp per 500 rpm? Just for a little comparison my old 355 had 12.6:1, a smaller cam and good bowtie heads and similar other parts to yours and it dynoed ( on a superflow 901 )way less than your desk top said (it made 468 hp) but the real info was not how much hp it made ( because who really cares about dyno numbers) but at what rpm and it was peak @ 5900 the cam was 254*/259*@ .050 we shifted at 6200 rpm to go the fastest and at 3000 lbs it went 123 mph but it was at about 1500 da not 5000 da like SIR has. I would play with shift points at the track not the desktop the track is the "real dyno".

[Bowtiestang]

I wouldnt even consider the info on the desktop dyno, Have you ever seen a real dyno sheet on an enige will make 40-50 hp per 500 rpm? Just for a little comparison my old 355 had 12.6:1, a smaller cam and good bowtie heads and similar other parts to yours and it dynoed ( on a superflow 901 )way less than your desk top said (it made 468 hp) but the real info was not how much hp it made ( because who really cares about dyno numbers) but at what rpm and it was peak @ 5900 the cam was 254*/259*@ .050 we shifted at 6200 rpm to go the fastest and at 3000 lbs it went 123 mph but it was at about 1500 da not 5000 da like SIR has. I would play with shift points at the track not the desktop the track is the "real dyno".

My cam specs are...

Dur@.020 294/306
Dur@.050 258/269
.631 lift both i&e
LS 106 cam installed @ 104

I called Comp cam today and spoke with the cam dudes they think 7000 was to high a shift point for my combo....will play a little bit the weekend at Firebird. Comp thinks I should be shifting at 6200-6500...will up date later..

[sc racing]

If the weather is good at Firebird Im thinking 10.95@123.

[Bowtiestang]

If the weather is good at Firebird Im thinking 10.95@123.

I hope it runs in the 10's....I will take a 10.9999999 But with my luck it will run a 11.000000

[Bowtiestang]

If the weather is good at Firebird Im thinking 10.95@123.

11.03@124 I knew it