SF Sizes

[Chad Speier]

How can a bench become generous or loose if it's NOW reading properly?

Sorry, all you just proved to me is your bench isn't calibrated properly!

The SF bench will read low with ANY properly prepared sharp edge plate, not just the PTS...

The industry standard is 28". Putting a plate on a bench that needs another calibration is insane.

[65mustang393]

My SF300 and 600 seemed pretty close on the intake. About 5% difference on the exhaust, so I know what you mean about SF benches reading differently.

[65mustang393]

The data is what my SF300 and SF600 showed vs the PTS cal plate. Nothing more or less.

[Chad Speier]

The data is what my SF300 and SF600 showed vs the PTS cal plate. Nothing more or less.

Shows your bench calibration is low/wrong, just like mine.

Look at this. This is real World, straight from Reher Morrison and Darin who cares about this being proper like I do.

Darin has a 30 year old SF600 with Audie. Uses sharp edge plates and square hole plates to calibrate. I've had all my plates across his bench. My point is, does he need to but an asterisk next to his work as well?

LIFT RM///PTS///SFwEL///Man
.200 147//145//143//133
.300 216//220//217//207
.400 281//281//281//260
.500 321//325//323//315
.600 346//349//347//338
.700 355//355//354//345
.800 366//367//363//352

The manometers are wrong! The calibration plate on the bench is wrong! Some could see it as the manometers being correct, and the other is wrong.

[DaveMcLain]

I really think that you would find that if you tested on a few SF 600's that all of them would read differently and that yours is right in there with all of them one way or another and reading low by between 3-6% on the intake side. I don't think it's the manometers or calibration orifice plate but rather the measurement plate in the SF600.

[65mustang393]

The data is what my SF300 and SF600 showed vs the PTS cal plate. Nothing more or less.

Shows your bench calibration is low/wrong.

Look at this. This is real World, straight from Reher Morrison and Darin who cares about this being proper like I do.

Darin has a 30 year old SF600 with Audie. Uses sharp edge plates and square hole plates to calibrate. I've had all my plates across his bench. My point is, does he need to but an asterisk next to his work as well?

LIFT RM///PTS///SFwEL///Man
.200 147//145//143//133
.300 216//220//217//207
.400 281//281//281//260
.500 321//325//323//315
.600 346//349//347//338
.700 355//355//354//345
.800 366//367//363//352

The manometers are wrong! The calibration plate on the bench is wrong!

Ok, SF is wrong. Make sure you state that when you advertise your numbers. Something like "An SF bench is incorrectly calibrated and will show readings 3-4% lower than mine listed here."

Sounds ridiculous right? It is, but what happens every time one of your heads goes on a SF bench and reads 4% low? That customer is going to blow up your phone wanting to know why and then figure out if he believes you. If he doesn't, then he's going to MF you, the "bogus" results he got, and the amount he paid to get "bogus" numbers.

Once he runs the number, he'll be fine but how many of his buddies did he MF you to in the meantime?

[65mustang393]

Chad, you have a bit of an issue on your hands. You're honest and show real results, so you're screwed by the hordes of low reading SF benches out there saying your results are wrong.

I've got an open mind and I'll play devils advocate. People drop serious coin on professional head porting results (probably more than I paid for the SF600FC) and if they feel like they've been cheated in the slightest... oh brother. It's on.

[Chad Speier]

The data is what my SF300 and SF600 showed vs the PTS cal plate. Nothing more or less.

Shows your bench calibration is low/wrong.

Look at this. This is real World, straight from Reher Morrison and Darin who cares about this being proper like I do.

Darin has a 30 year old SF600 with Audie. Uses sharp edge plates and square hole plates to calibrate. I've had all my plates across his bench. My point is, does he need to but an asterisk next to his work as well?

LIFT RM///PTS///SFwEL///Man
.200 147//145//143//133
.300 216//220//217//207
.400 281//281//281//260
.500 321//325//323//315
.600 346//349//347//338
.700 355//355//354//345
.800 366//367//363//352

The manometers are wrong! The calibration plate on the bench is wrong!

Ok, SF is wrong. Make sure you state that when you advertise your numbers. Something like "An SF bench is incorrectly calibrated and will show readings 3-4% lower than mine listed here."

Sounds ridiculous right? It is, but what happens every time one of your heads goes on a SF bench and reads 4% low? That customer is going to blow up your phone wanting to know why and then figure out if he believes you. If he doesn't, then he's going to MF you, the "bogus" results he got, and the amount he paid to get "bogus" numbers.

Once he runs the number, he'll be fine but how many of his buddies did he MF you to in the meantime?

I don't have any problems with guys that know how to calibrate a flow bench. In fact, I really have no troubles at all. I have problems with guys that have cement minds, and accept the fact that because it's a SF it's correct. Well I just proved what I already know, not only with the readings, but with a SF owner. Again, I know how my PTS bench compares to other real World record setting porters, and my PTS is closer to being right than high... Just wanted to see how the industry standard compared and help the DIY users along the way...

[Chad Speier]

Chad, you have a bit of an issue on your hands. You're honest and show real results, so you're screwed by the hordes of low reading SF benches out there saying your results are wrong.

I've got an open mind and I'll play devils advocate. People drop serious coin on professional head porting results (probably more than I paid for the SF600FC) and if they feel like they've been cheated in the slightest... oh brother. It's on.

You think? I'll post both numbers, I don't have any issue with that!!!! You really think that changes the fact if your stuff works, it works? The only issues come from guys who put faith in flow arounds, and bogus calibrated benches, and even skewed magazine articles.

I have no issue on my hands...

And for the record, NOT ALL SF benches read low! The Parks bench reads within 2 cfm of my PTS. Darins, other engine customers I have. Just the guys who have owned it for years and have never calibrated it properly because it's blue. Then when they do, are scared to change the readings. OR, just accept it.

[blaktopr]

SF number are low. They probably calibrate it wrong and after issuing over ten thousand benches, they won't admit a mistake.

Problem is that unless every SF owner is willing to bump their numbers by 3-4% you're gonna have people who cry foul because 350 PTS cfm is only 336-339 SF cfm.

So if you have a home made bench, just save yourself a lot of grief and keep some "SF numbers" to go along with the real ones.

Funny thing is that I bet alot of DIY bench guy's heads still do better in performance and flow than the others even after throwing a % factor in to try to lower them to match SF#'s.

No doubt you're right, but are we talking ability or relative equipment readings here?

I'm talking ability. It seems anyone interested in making sure their stuff is right or even build their own bench, seem to create better ports. (Shape and flow). Its how much one "looks" at the science around them. I can tell you that even one of my ports on a "competitor's" bench, even if it reads lower than mine, will still be higher than their best. And I will be showing them too much other vital info regarding cross sections.