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  #226 (permalink)  
Old 11-01-2013, 07:31 PM
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The drag strip never lies. When you get it set up best you can take it to a drag strip on some sticky tires and test it .. The MPH from the 1/4 mile ET slip combined with the real car weight + drivers weight tells the tale of how much power it is really making.
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  #227 (permalink)  
Old 11-02-2013, 03:46 AM
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Ya what he said

My Chart shows 50 Upper 45 Lower = -9.0 Underdriven
And 52 Upper 45 Lower = -13.5 Underdriven
So 51 Upper 45 Lower would be -11 Underdriven

And I also agree the power seems low, do you know if it was a Dynojet or Mustang Dyno ??? and were the numbers SAE, Net, or Uncorrected ???
Those #'s could be off by as much as 15% and as also said the 1320 dont lie, MPH will tell EVERYTHING.

AMOF I'm leaving right this sec to go out of State and take my 351W down the 1320 for the last time this season, (hoping for a 10.5 this time out)
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  #228 (permalink)  
Old 11-02-2013, 06:10 AM
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Vacuum secondary throttles opening?
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  #229 (permalink)  
Old 11-02-2013, 10:06 AM
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Quote:
Originally Posted by F-BIRD'88 View Post
When calibrated correctly chassis dynos give very modest power numbers.
There are many factors.
You should have removed the engine and dynoed it on a real engine dyno.

the blower drive ratio is 11%under. If you are sure of the carb jetting
you can change it to 11% over by reversing the top and bottom pulleys.
Reduce the timing and sneek back up on it once verifying the tune
and knock tolerance.
The exhaust many be killing it.
Verify dyno calibration and setup. And weather correction factor etc.

Even at 7psi and 11% under drive I would expect more horsepower from it.
The ignition system is very suspect.
Tire traction.. A transmission issue.
hi firebird

wish I could change the pulleys around but I cant move the bottom one. its been made to fit over the harmonic balancer , so am thinking of ordering the same size as the bottom one and running it 1 to 1 . seems the holley/weiand charts are very out for my engine, I understand they do say its only a guide. but its way out. meant to be 11psi on their charts but not even seeing 7psi at 6000 rpm,

on the ignition I cant see any problems, new plugs , double checked with a timing light. I was at the dyno for 6 hrs with them, carbs off 4 times, re jetting, changed the vac sec diaphragm's. once it made max power it didn't move even when it was jetted richer , secondary's worked fine, pvs coming in nicely

they sprayed some compound on the tires to make it grip, I do have a auto so am sure im loosing bhp through trans, but I checked it before they started and it was full of atf.

I have racked as most brains as I can and all point towards more boost.

points noted and will double and triple check plugs ,auto fluid. I have took my carbs off AGAIN and am stripping them down tomorrow just to double check there is not debris or obstructions.
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  #230 (permalink)  
Old 11-02-2013, 10:17 AM
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Originally Posted by F-BIRD'88 View Post
Vacuum secondary throttles opening?
yes , I watched them open , was sticky before so we changed both diaphrams. check ball has been removed, I boost ref the primary metering blocks so the pv's see manifold vacuum as we discussed a while ago. didn't do the work on the carb base. did it using the take off tubes already on the primary metering blocks and opened the channel to the pv's
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Old 11-02-2013, 10:33 AM
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Quote:
Originally Posted by ProStreetRob View Post
Ya what he said

My Chart shows 50 Upper 45 Lower = -9.0 Underdriven
And 52 Upper 45 Lower = -13.5 Underdriven
So 51 Upper 45 Lower would be -11 Underdriven

And I also agree the power seems low, do you know if it was a Dynojet or Mustang Dyno ??? and were the numbers SAE, Net, or Uncorrected ???
Those #'s could be off by as much as 15% and as also said the 1320 dont lie, MPH will tell EVERYTHING.

AMOF I'm leaving right this sec to go out of State and take my 351W down the 1320 for the last time this season, (hoping for a 10.5 this time out)



how did you get on ??

I agree its 11% underdriven . what's your thoughts on going 1 to 1 ?

haven't a clue on dyno or sae numbers etc. suppose I thought its their job to do all of that ? give me some pointers to ask them ?? the dyno works the opposite to a alternator and uses electric current to operate . does that help ?

they did say that you "yanks " lol . do inflate dyno numbers ?? ie the bhp over there is different to here ? I know that seems mad and I don't think they mean its a different value . for example, they had some dick head who had a corvette and he raved that it was a 500 bhp car. the most the dyno saw was 375 . now that could of been 500 bhp at the fly wheel ?

think they have just had a few big v8s go in there saying this and that and when it comes down to it the power isn't there.

they like the idea of my water inj. said to get it as good as it can then slightly back off and use water inj to add some intercool charge.

have heard that methanol rots alu ? failing me getting a refrigeration coil put into the tank what other liquid can I use with water to provide intercooled effect ? I read somewhere on here windscreen wiper cleaning liquid -screen wash ???? really ??


what boost you run with blown engine ? what comp ratio ?
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  #232 (permalink)  
Old 11-02-2013, 07:28 PM
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The "eddy current" type dynos give the most conservative power numbers.
Transmission: There is more to it than just fluid level.
High stall converter efficiency.
High /direct clutches.
Tire slip. Tire distortion on rollers.
Exhaust

Last edited by F-BIRD'88; 11-02-2013 at 07:37 PM.
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  #233 (permalink)  
Old 11-02-2013, 09:29 PM
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Originally Posted by mustang 671 View Post
how did you get on ??

I agree its 11% underdriven . what's your thoughts on going 1 to 1 ?

haven't a clue on dyno or sae numbers etc. suppose I thought its their job to do all of that ? give me some pointers to ask them ?? the dyno works the opposite to a alternator and uses electric current to operate . does that help ?

they did say that you "yanks " lol . do inflate dyno numbers ?? ie the bhp over there is different to here ? I know that seems mad and I don't think they mean its a different value . for example, they had some dick head who had a corvette and he raved that it was a 500 bhp car. the most the dyno saw was 375 . now that could of been 500 bhp at the fly wheel ?

think they have just had a few big v8s go in there saying this and that and when it comes down to it the power isn't there.

they like the idea of my water inj. said to get it as good as it can then slightly back off and use water inj to add some intercool charge.

have heard that methanol rots alu ? failing me getting a refrigeration coil put into the tank what other liquid can I use with water to provide intercooled effect ? I read somewhere on here windscreen wiper cleaning liquid -screen wash ???? really ??


what boost you run with blown engine ? what comp ratio ?
The track was bad today, we had 2 rain delays, 2 MASSIVE OIL DOWNS, and I spent probably an easy 4 hours sitting in the staging lanes
Deep Staged by mistake on the first pass and ran a 10.92, then ran a 10.81 and the best ET of the day was 10.70 (it went 10.66 & 10.61 at Atco earlier this year) Atco is a much better track and closer to sea level where Island is up in the mountains at higher elevation so I guess I cant complain since we took it home in one piece

As for the Street Beast, my Sierra makes crazy power so I dont need much boost. I'm running a 56 T Upper Pulley + 52T Lower Pulley =’s 8 lbs of Boost @ 6,000 RPM (-5.5 Underdriven). At that set up the compression correction works out to 13.1 Compression. If I switch the pulleys around it's 12 lbs of Boost @ 6,000 RPM (+5.8 Overdriven) With that set up the compression correction works out to be 15.1

Mine sounds totally different than yours, I made this a few days ago on my phone. Just a little put put around town...


A few pics from the track today
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  #234 (permalink)  
Old 11-03-2013, 10:53 AM
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Somewhere above you were talking about the boost not being what the charts showed. It's possible you have a small case 6-71. Not a problem but you just have to spin it faster. Hopefully your blower is not messed up. I've run into at least 6 this year with too little clearance on the rear of the rotors resulting in a galled case and rotors.

Since you can't change the bottom pulley the only choice is the top one. You may have to make a spacer under the blower. 1/8, 3/16 and 1/4 in are common SAE sizes. Adjust for metric material if you need to. The reason for the spacers is that you you may run out of room for adjustment on the idler.
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  #235 (permalink)  
Old 11-05-2013, 12:14 PM
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hi pro street rob

the sierra sounds nice on the rd. and congrats on those times. must be hard when its raining. here in the uk the weather has turned so don't expect I will be getting out much for a few months, prob not a bad thing. try and get some nice cold dry days and put some miles o it before the summer heat comes. less chance of it getting too hot. your pulley sizes are interesting. seems the charts aren't any use and just a very very rough guide.
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  #236 (permalink)  
Old 11-05-2013, 12:16 PM
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Somewhere above you were talking about the boost not being what the charts showed. It's possible you have a small case 6-71. Not a problem but you just have to spin it faster. Hopefully your blower is not messed up. I've run into at least 6 this year with too little clearance on the rear of the rotors resulting in a galled case and rotors.

Since you can't change the bottom pulley the only choice is the top one. You may have to make a spacer under the blower. 1/8, 3/16 and 1/4 in are common SAE sizes. Adjust for metric material if you need to. The reason for the spacers is that you you may run out of room for adjustment on the idler.
hi bent wings.

thanks for the comment. I can get a different size belt so haven't got any issues with the tensioning luckily. that's interesting you mention it could be a smaller case blower. will look into that. ta

also I looked at my blower before I brought it years ago and also more recently when I o-ringed out the inlet manifold. the rotors are good. no scores. no leaks from the blower either.

Last edited by mustang 671; 11-05-2013 at 12:44 PM.
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Old 11-05-2013, 12:38 PM
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hi all and those just following . I really could do with some input on the following. and I know it may be a wet finger in the air and hope ????


so currently I have a 45 tooth bottom and 51 tooth top pulley. I got 7psi at 6000rpm but had so much more to go and only produced 330bhp.

have spoken with the dyno guys again today and also a supplier over your neck of the woods who can supply me with a 42 tooth cog for $115 + delivery which isn't bad. my questions is , can anyone hazard a good guess- work out? how much boost that would get me to ? so 45 bottom and 42 top

my engine started at 7.48to1 comp ratio but since then I have changed from a felpro normal head gasket to a felpro mls one. nothing else has been changed apart from it being homed out just slightly and a bit of piston to bore wear but prob nothing to be honest as the engine hasn't had much use. the orginal block is 30 thou over and I have kb hyper pistons - but I do now have a new crane custom grind cam which I posted about earlier which is a roller cam.

I have large headers which collect and go into 3" exhausts . under and out the back. the car was for racing before I imported it so it has a large dual exhaust.

I have a c6 with a high stall b+m torque converter. Been uprated with reverse manual shift pattern body.

my thoughts are that the combi would give around 10-12 psi ? which would be a lot better , I will have the water inj running with this higher boost. I can easily get hold of 99 octane fuel to use. only 5p a litre more . but still bloody 6.58 a gallon

help !!!!!!!
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  #238 (permalink)  
Old 11-05-2013, 12:46 PM
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Quote:
Originally Posted by F-BIRD'88 View Post
The "eddy current" type dynos give the most conservative power numbers.
Transmission: There is more to it than just fluid level.
High stall converter efficiency.
High /direct clutches.
Tire slip. Tire distortion on rollers.
Exhaust
hi fire bird.

have just posted below my auto c6 spec. its all new and good quality stuff.

tyres are brand new. they sprayed some goo onto the rollers for it to grip.

the exhaust I also mentioned. but agree if it had a stainless all the way through im sure it would flow better. but it is big bore . and I have nice long headers. large bore aswell.
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Old 11-05-2013, 12:50 PM
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Vacuum secondary throttles opening?
yes they re fine
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  #240 (permalink)  
Old 11-06-2013, 12:25 AM
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yes they re fine
But are they opening fully @ WOT?

Carb pri and sec jetting? timing?
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