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Right. But the TQ scale and the HP scale aren't the same.
So, in the top graph (the max 340 one), you see about 225 hp at about 5252 RPM. You also see about 225 Ft-Lbs of TQ. It's just that the 225 HP is a lot lower on the page than the 225 Ft-Lbs.
In the bottom one, you see about 205 at 5252 RPM. On both.
It's odd, but it's how it's presented, not how it's calculated.
It's odd, but it's how it's presented, not how it's calculated.
It's not really odd at all. All dyno software that I've used has a simple check-box for "scaling" and if you don't check that box the software scales the charts to look that way.
Originally Posted by James Bailey
Note how ALL their dyno runs hp tq cross at 5252 RPM
again the 5252 RPM is where the two, torque and horsepower must cross because of how it is calculated.....
Her Jim, maybe this will make sense. Below are the EXACT same dyno runs, just with different HP & Torque scaling:
I'm used to seeing dyno charts where the TQ and HP use the same scale. (bottom one)
On those, the TQ & HP cross at 5252. They have to. It's part of the definition of "Horsepower".
On the top one, the scales are different, adjusted so that each curve has a "best fit". But if you read closely, HP & TQ are the same at 5252, that number is just in a different place on the "paper".
Which is how the ones up thread are presented.
So they look odd to me. And apparently to Jim too.
O K a deviation from the norm.....and makes it look very odd indeed Much like Euro dyno charts with the different units of measurement and different normal crossover RPM.. different definition. different formula.
Those velocity stacks will be highly efficient at one frequency (RPM). That's great if you've got the gears to run near that peak.
Don't get me started on graphing data. Oh, wait, you did. People like pictures and there's a lot of information is the graphs but it can be deceiving depending on the scales. What units? Zero based or just the range? What's the max value? The traditional HP vs. Ft*lbs graph works surprisingly well as the units are in the same numerical range.
interesting dyno charts..... 5252 RPM is oddly not the crossover... Are you sure this was stock camshafts ?? and it is aftermarket ECUs.
home grown Titanium exhaust as well.....
why would you think they are odd and why even care of the cross over?
cross over only happens at 5250 when both the tq and HP are the same scale, and tq is measured in ft-lbs.
Also worth mentioning that the big jump in horsepower with the carbon fiber individual runners for Fan and Anderson was the LAST STEP of the process on big stroked, big cammed, race exhaust engines.....far, far from a "stock" 5.0 engine !!
yes, it was the last step, and im sure what you are getting at here is that the big bottom end could take more advantage of the intake as it might have been severly restrictive. the thing is JIM, with air flow, if it helps the 6.5 lter,, it will help the 5 lter too.. but , the question is by how much. i predict that a bolt on intake , like the CF intake, would make a stock 5 liter to make near 400rwhp, at least 400rwhp at the crank.
Originally Posted by GregBBRD
You mean because these manifolds signifcantly reduced the low and mid range torque on a 6.5 liter engine and would have turned a 5.0 into a joke?
Or because they never made it past the prototype stage and the pieces were literally held together with glue and bondo?
Greg, no... you did loose low end torque compared to the big motor HP dyno runs, , but the high end HP is what wee all want and will use (street or race) and it would help, JUST as it does on the vantage and mustangs with 4.3 to 5 liter engines.
bolt one of these intakes on a stock 5 liter and it will be a monster. we have been talking about this for 10 years now and i cant believe no one has done it!! Carl and you have made them, but no one has put it on a stock 5 liter! it will work and work well!!
yes.... the "prototypes" were crappppy "bondo" construction like........
but keep in mind, just bolting them on with home depo tubing, a hand carved MAF assembly and more "bondo" they bolted on 100hp!!!! with NO other changes!!
420rwhp from marks to 520rwhp for both mark and Joe's
Originally Posted by James Bailey
Both actually....... just did not wish for Kibort's post to make people with stock S-4s think there was an easy 80 HP out there just waiting for them with a simple manifold swap and "no other tuning changes" .
Too much like the guy with a 305 cu inch chevy bolting on a huge 1050 CFM Holley on a tunnel ram and wondering why it did not work out so well
no, thats nothing like bolting a carburetor.. seriously?? its like putting the PROPER intake on the 5 liter and watching it wake up!! your analogy is like someone putting on a large throttle body.. anderson and fan did this.. it didnt do anything... they also hogged out the intakes.. no gains... when they put on the CF intake, HUGE gains were made!! the intakes on the S4 are garbage. put on this intake and yes, 50 to 80hp will be gained with NO tuning... the 928 is auto tune for the most part anyway. i did no real "tuning " and went from 280ish to 335rwhp with only a twist of a RRFR. AND, the 84 went from 177rwhp to 290rwhp with the same twist and NO other changes.
again, anderson got 520rwhp on his last dyno runs with no tuning. it was a rag tag set up, with piping from home depot!! PVC piping for a MAF with a MAF hot wire , glued in it...... It made more gains that the entire greg brown stroker made on the stock set up!! 100hp!!!!
Originally Posted by James Bailey
Right but that was no stock engine....custom rods, pistons, alloy heads and ....big camshaft ! and netted about 60 HP. Note how ALL their dyno runs hp tq cross at 5252 RPM
again the 5252 RPM is where the two, torque and horsepower must cross because of how it is calculated.....
again, why would you care of the intersection point?
they only cross if the two scales are the same and you are using ft-lbs as torque. otherwise, they might NEVER cross as they do iin may European metric dyno programs!
Those velocity stacks will be highly efficient at one frequency (RPM). That's great if you've got the gears to run near that peak.
Don't get me started on graphing data. Oh, wait, you did. People like pictures and there's a lot of information is the graphs but it can be deceiving depending on the scales. What units? Zero based or just the range? What's the max value? The traditional HP vs. Ft*lbs graph works surprisingly well as the units are in the same numerical range.
why would it be deceiving?. the HP curves are very explicit and that really is all you need. torque is there as well, and shows peak values if you need that info as well. you have the max values? you have the range? dont you?
as far as gears, thats a 1st and top gear issue.. all the middle gears will work regardless as thats more of a spacing (closeness) issue.
If 99 out of 100 dyno charts is scaled the same and 5252 is the crossover due to the formula it is a convention...... You have to admit when looking at the first two dyno charts the first one LOOKS way better ...and NOT simply because IT MAKES MORE HORSEPOWER !
I can understand your frustration with running your stroker engine with a "restrictor plate" not sure that means the S-4 intake is garbage just not suited to your big modified engine which of course makes perfect sense as it was designed and engineered for a stock 5 liter with stock exhaust and cats.....so what was your point ??
If 99 out of 100 dyno charts is scaled the same and 5252 is the crossover due to the formula it is a convention...... You have to admit when looking at the first two dyno charts the first one LOOKS way better ...and NOT simply because IT MAKES MORE HORSEPOWER !
I can understand your frustration with running your stroker engine with a "restrictor plate" not sure that means the S-4 intake is garbage just not suited to your big modified engine which of course makes perfect sense as it was designed and engineered for a stock 5 liter with stock exhaust and cats.....so what was your point ??
I'm not sure what Kibort is saying, because I have him "shut off". (Nor do I care.)
However, I agree it is extremely odd to have results using two different arbitrary scales. Mixing different scales, which makes results look way better than they actually are is a bit of a "snake oil salesmanship" tactic. When I see people fussing around with results to visually amplify their efforts, I instantly become very suspicious....which is the point I believe that Jim is making.
Regardless of his tactics, if the results were completely from this guy's intake change, that is good stuff. (I know less nothing about the cars he is working on....are the original results from a stock engine, or from the engine in the picture with the titanium exhaust? (Are the results actually only about the intake system or is the exhaust also a part of the equation?)
Like I said....I instantly become very suspicious.
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
If 99 out of 100 dyno charts is scaled the same and 5252 is the crossover due to the formula it is a convention...... You have to admit when looking at the first two dyno charts the first one LOOKS way better ...and NOT simply because IT MAKES MORE HORSEPOWER !
I can understand your frustration with running your stroker engine with a "restrictor plate" not sure that means the S-4 intake is garbage just not suited to your big modified engine which of course makes perfect sense as it was designed and engineered for a stock 5 liter with stock exhaust and cats.....so what was your point ??
I guess when you look and deal with performance curves for a living for over 12 years, you end up NOT being impressed with "shapes, and interceptions".
It makes more hp and my being impressed, ends there. I can understand how intuitively, once curve looks like its better than it really is if your focus is not in the right place. if you train yourself to look at HP only, you solve much of this issue. no need to look at torque, as its incorporated into the HP curve.
your second comment,i have to reply, "what is YOUR point". yes the S4 intake is very restrictive. doesnt matter if its designed for a stock 5 liter bottom and cats and exhaust, but ill tell you this, there is little difference in MANY of the 4 to 5 liter bottom ends in the world for production cars... the diff is MAINLY the intake. just look (as i said, again) the vantage you bought for your daughter..) 4.3 liter making 80 more HP than our 5 liter? why is that.. compression isnt that much higher. cams are not much more radical... heads dont flow that much more.... ITS ALL INTAKE for the most part.
we can solve this debate if ANYONE puts on an improved intake like the CF intake and we dont see stellar results!! we willl and i hope its done very soon.
Greg should do it, Carl should do it... and do it so its a bolt on affair. you wont need fancy "tuning" to get safe fuel air ratios and the timing , as moderate as it is, is safe as well. sure, you wont get the 100hp that mark and Joe got, but i bet you get 50!
does or will, that prove the intake is restrictive for the "stock S4" ? you bet!
Originally Posted by GregBBRD
I'm not sure what Kibort is saying, because I have him "shut off". (Nor do I care.)
However, I agree it is extremely odd to have results using two different arbitrary scales. Mixing different scales, which makes results look way better than they actually are is a bit of a "snake oil salesmanship" tactic. When I see people fussing around with results to visually amplify their efforts, I instantly become very suspicious....which is the point I believe that Jim is making.
Regardless of his tactics, if the results were completely from this guy's intake change, that is good stuff. (I know less nothing about the cars he is working on....are the original results from a stock engine, or from the engine in the picture with the titanium exhaust? (Are the results actually only about the intake system or is the exhaust also a part of the equation?)
Like I said....I instantly become very suspicious.
Greg, you can shut me off, but on this forum i will respond and nice way to cast an insult to a fellow rennlister.... very curious how someone like you can be so "impressed" with a differnet configuration of a HP curve. no, they dont look any better than they are...... its not snake oil or salesmanship, its just numbers and a very simple graph. that usualy is done when they EXPAND the scale to make 5hp look like a 20% gain due to x axis scales.. in this case, that isnt.
anyway as i always say, i hope you can apply the intake solutions to the stock 928 world, after all, you are self proclaimed best at it all. personally, i think it woudl be a smart move and would be a HUGE sucess to make a bolt on intake that uses stock components. most other marques have it, but we dont!
you or carl can chance that!
I thought Greg was in business a lot longer than that.
That's backwards. The multiplication by RPM obscures the data.
For real analysis just look at torque. It shows the changes in BMEP which includes VE, timing and mixture issues. Much more clear. Period.
and taxi cab drivers should be recruited to win the indy 500.
if you know what you are looking for, its all on the graphs and there should be no surprizes. I dont think greg spent much of his time looking at dyno graphs, and if he did, he was looking for specific things or heck, maybe too general things. the fact that he thinks that there are differences in dynojet 248e should be telling to you.
Glen, as far as being clear, "period"... reallly? it all depends what you are lookinig for in those curves. and what do you call" real analysis"?
for example, if i was going to find best shift points...
HP curve wins
if i was going to find who would win vs another car
HP wins
looking at efficiency areas, is where you are right. but thats now what most look for in their "analysis " of the power/torque curves of their cars.
so, in summary, torque is NOT the most "real" analysis... that depends what you are looking for. with HP, it already includes torque and the RPM, so you get more information to be utilized in making an informed decision.
RPM doesnt obscure ANYTHING... in fact, without it, you would have 0 ability to take any information other than your BMEP points. I you mean torque RPM plots, and yes, i have no issue with only using it as well, but for things i look for, its another stage of multiplication i have to use, to find things like shift points ,where i can just use gear spacing to find it quickly, rather than multiplying it all out. both ways work..
for example... i can look at the 340rwhp ferarri plot and see 315hp average from 6000rpm to redline 8900.
pull out my 335rwhp stock S4 with GTcams and headers and see 320rwhp. I can see its much more streetable due to the wide HP band. sure, you cand find that same info but it will take MUCH more work to do the "analysis".
Mark, I have something in mind - If you remember, I managed to get 438rwhp out of a 5.4ltr GTS based bottom end with higher compression, Colin's cams and BMW ITBs. The engine is streetable and there is tons more power left on the table. Why am I confident in saying this - because I am not running an airbox! BMW spent countless hours giving the bellmouths the required radius and to take advantage of the plenum around them. I am running them FORD GT40 style, which robs power. Two reasons - packaging and time/money.
Now though, I have access to someone who is cheap and keen to make a plenum out of carbon/Kevlar. I have also been able to glean some airboxes on Tuscan race cars. Last but not least, we have been experimenting with molds and silicon hoses with "funny" shapes. Stay tuned (pun intended)
03-06-2016, 06:21 PM
