Stepped Covers and Bushings in 2.6" or not?

[smokin habit]

This is called competition without people pushing the limits the sport would never grow.If you try to make every truck pull close to the same the crowds will leave and so will the money.Not trying to make anyone mad just stating my opinion,if you cant afford to upgrade to the competion level then drop back to work stock.I have taken my losses the past few years the idea is to learn from it and come out stronger next year.If we want to get real technical the true 2.6 off the shelf chargers out of the box will not pass the 2.6 plug test the plug is a hair bit loose due to smoothing the housing after the machining is complete.

 

[BluegrassDiesel]

As for your ignorant rant about money.. LOL... I don't know about the others here. My truck was paid for in CASH the day it left the dealership. I've spent an insane amount of money on mods to build a true 2.6" truck and because a bunch of guys who can't cut the mustard in 2.8" have dropped down to 2.6" I have ZERO chance at making the front of the pack!

Hell I'll admit it! I'm stretching the rules of what a true 2.6" truck should be and still can't compete only because I want to run a TRUE 2.6" charger!! I've got a full competition port job on the head, with sheet metal intake, aftermarket cam, coated pistons, treated and shot peened 12V rods and all the other goodies to match.

I assure you! I've spent the money! That's not the issue! So lets quit... *bdh*

You cant just throw money at it and expect to win. Money is only part of the equation. Knowledge and skill play a large role as well.

 

[nwpadmax]

Johnboy and 05Smoker have it 100% correct...and I have been saying for years, unless an organization has the cojones and the willpower and staff to enforce an exducer limit, this is all wasted breath.

The concept of "off the shelf" 66mm is just totally naive. Convicted1, you're showing how little you understand about how chargers are built and how they function. I'd suggest getting a good book on the subject and coming back when you've got a better grasp on things.

You wanna go yell at someone? Go yell at the organizations who are content with the rules the way they are.

If the rest of us build as far as the law allows, don't blame us. Blame the rule writers - because there's a ton of 'em who don't care one bit about this. Just get a good number of trucks in the class (no problem the way it is now) and put on a good show, and that's all there is to it. Money in the bank.

Jump up and down all you want, this is the entertainment business we're in. Don't be yelling at the other dancing monkeys. Yell at the guy who owns the circus if you think the circus sucks.

One more time: only an exducer limit will achieve what you're wanting.

 

[Convicted1]

Well if I'm so misinformed point me in the direction of this "Book" and I'll be glad to take a look.

I have never said I know it all. I may very well have a misunderstanding of the correct terminology.

One more time: only and exducer limit will achieve what you're wanting.

Thats exactly what I and some others in this thread have said! Why repeat it as if we don't understand!?

For there to be a true seperation between the 2.6 and the 2.8 classes something has got to change. THIS IS THE ONLY THING THAT WILL TRULY CHANGE THE OUTCOME!

As stated earlier.... I'm having a charger built to the current rules of the 2.6 class for next season. SO THIS ISN'T JUST ABOUT ME! I'm changing my build to take advantage of the rules as well. I just don't think it's right!! It shouldn't be this way!

 

[Convicted1]

You cant just throw money at it and expect to win. Money is only part of the equation. Knowledge and skill play a large role as well.

Well... I suppose you're speaking about how to tune, as well as reading the track when actually pulling.

Well the tuning thing I'm pretty sure I've got close. I've spent quite a bit of time testing different setups on the dyno. Yeah... Dyno tuning is only good for so much, but it's a start.

And as far as reading the track when pulling... I have put the top trucks drivers around here in my truck and the outcome hasn't changed much. So I doubt thats as big of an issue as you'd think.

Once again... I'm not sayin' I know it all. Yet this isn't just about me either. This is about the class as a whole.

 

[DISTURBED]

The Pro 52 has a 71mm inducer.

The pro is 71mm but there are other versions of the 52 with a 67mm inducer that will put a serious whupping on a S300. I know...I had one.

Sorry, The one i measured was a tick over 66mm.

The problem is there are very few that havnt been altered, you can argue this till the sun comes up but most charger that you buy that is not cummins, ford, or chevy specific has to be altered in some way or another in order for them to perform on these trucks, at which point they become a custom charger whether you want to believe it or not. You can even argue that say II, HTT, and ATS chargers are all custom chargers so they in my opinion would be off the list of chargers that can be used. So i say leave the rule the way it is.

 

[Smokem]

Sorry, The one i measured was a tick over 66mm.

Must have been an HX52.

 

[Convicted1]

Well if I'm so misinformed point me in the direction of this "Book" and I'll be glad to take a look.

I have never said I know it all. I may very well have a misunderstanding of the correct terminology.

I'll be the first to take constructive criticism and as such....

Well... per your suggestion, I went and did some reading. Still not 100% on the level with all this, but I believe I now understand why my statement was inaccurate.

My Source:

TurboByGarrett.com - Turbo Tech102

A 2.6" INDUCER is what the requirement of the class is currently. There is at this point however, no limitation on the Exducer size of the compressor wheel.

I apologize.. I did not take into account the fact that there is as of yet to be a direct correlation (Set Trim) between inducer and exducer size for the 2.6" class.

So to put a limitation on the Exducer size would be very difficult for the simple reason of you'd be limiting turbo charger design to an almost crippling degree.

Do I have a (newb level) proper understanding now? This is not a smartass question... I just want to make sure I have my facts correct before I proceed with my next arguement....

 

[Convicted1]

One more question.... 2.6" Inducer comes out to roughly 66mm correct?

So wouldn't a true 2.6" charger be limited to only having a 66mm Inducer on the compressor wheel?

Not a charger with say a 2.8" Inducer on the compressor wheel that is "shrouded" by the actual inlet of the charger? (This is what I consider a bushing or stepped cover.)

Basically what I'm asking is are we (currently) judging the size based on the INLET or are we basing it on the compressor inducer size?

If it's based on compressor inducer size shouldn't making the ruling state that the inducer must protrude into the inlet eliminate the question as to whether or not the turbo is legal? If the Inlet measures 2.6" and the wheel protrudes into that 2.6" inlet... It would be a legal charger correct?

I wish I were better at drawing stuff in Photoshop.... Then I could put what I'm thinkin' on the screen and it might make better sense! LOL

 

[JOHNBOY]

I never stated this was an EASY fix! I stated it was a NEEDED fix! I guess I should have stated in the poll "Native 2.6" Wheels Only".
Does not change anything.



I don't know any of those guys, so forgive my ignorance, but how well would their trucks perform at a big event such as SDX?
Evan is the Ohio 2.6 champ 2 years running. Bennetts won the FPP 2.6 points this year and where second last year. As for Schieds who cares. One pull vs a whole seasons work.



Yeah.... I might have been a little peeved and "spouting" at that point, but once again, there are varying degrees of streetable. I can run my truck around town all day at 700HP and control the smoke, but the fact of the matter is, to run with the current 2.6" class, 700HP isn't enough. Any more charger and I'd have to loose the power I'm currently able to run around town with in order to control smoke with a bigger stepped cover or bushed charger.
Until you try you dont know that. S400 spool is not as bad as you think. Smoke before spool up actually hurts you. I get the best spool up with just a faint haze.

The point of the matter still is... The 2.6" class is way out of hand as it is and something needs to be changed. You got a better suggestion than turbo compressor size? There shouldn't be a need for more than the 700ish HP that can be made on a well tuned 2.6" charger.
Yes and no. I was not fan of the 2.6 thing when the idea came out 2 years ago. I was in favor of 2.5. I also was not infavor of just plug checking the housings. I said a long time ago that you would see stepped comp housing cover big wheels. I was right. The trouble is if the rules are to techincal they become very hard to tech. Plug testing is vary simple. Not perfect but it is better than adding rules that can not be easily teched. An exducer rule is a good example. While techincally superior is is a bugger to check in the truck

This came from the fact that the 2.8 class is currently DYING because of the blurred line between 2.6 and 2.8. Why would the 2.8 guys want to dump the money to have a competitive true 2.8 truck when they can just throw a stepped cover on and come play with the 2.6's?

There has never been a 2.8 class around here to die off.


EXACTLY! You don't have a 2.8 class because all the 2.8 trucks are currently pulling with the 2.6 class! LOL... How many of your 2.6" trucks are running a stepped cover charger or bushing! Guess what... If they are running either they belong in 2.8!
No we never ever had a 2.8 class. The trucks running in 2.6 around here meet the 2.6 rules so they are really 2.6 trucks

2.6" is the "Entry Level Competition" class in my eyes (and most others I think). I should have worded that differently in my orignal post. It should be for the guys with the super hot street trucks to have a place to pull without having to run with trailer queens.
Again you would be suprised how streetable some of the best trucks really are. Dmaxs can be very easily turned down and be very streetable. So can CR Dodges

You cant just throw money at it and expect to win. Money is only part of the equation. Knowledge and skill play a large role as well.

Bingo.

Well if I'm so misinformed point me in the direction of this "Book" and I'll be glad to take a look.
Start with this. Amazon.com: Turbo: Real-World High-Performance Turbocharger Systems (S-A Design) (9781932494297): Jay K. Miller: Books



Thats exactly what I and some others in this thread have said! Why repeat it as if we don't understand!?
I mentioned the exducer not you. Go back 3 pages and read your own posts.



For there to be a true seperation between the 2.6 and the 2.8 classes something has got to change. THIS IS THE ONLY THING THAT WILL TRULY CHANGE THE OUTCOME!
Get rid of the 2.8 class. Cures that problem LOL

As stated earlier.... I'm having a charger built to the current rules of the 2.6 class for next season. SO THIS ISN'T JUST ABOUT ME! I'm changing my build to take advantage of the rules as well. I just don't think it's right!! It shouldn't be this way!
Well it is what it is. You are never going to make everyone else change back because you cant hang with your present charger.

One more question.... 2.6" Inducer comes out to roughly 66mm correct?

So wouldn't a true 2.6" charger be limited to only having a 66mm Inducer on the compressor wheel?
66mm = 2.598" But many "off the self" "native" chargers like the SB66 will not pass tech because the cover is actually bigger than 2.65. Do a search you find threads about more than one "off the self" "native" charger that failed the plug test
Not a charger with say a 2.8" Inducer on the compressor wheel that is "shrouded" by the actual inlet of the charger? (This is what I consider a bushing or stepped cover.)

Basically what I'm asking is are we (currently) judging the size based on the INLET or are we basing it on the compressor inducer size?

Sort of. What the rules say is that the inducer bore in the comp. housing is the feature to be measured.

If it's based on compressor inducer size shouldn't making the ruling state that the inducer must protrude into the inlet eliminate the question as to whether or not the turbo is legal? If the Inlet measures 2.6" and the wheel protrudes into that 2.6" inlet... It would be a legal charger correct?
Yes and no. If the wheel must protude into the inducer bore you can still have the bigger turbos. Instead of just a stepped cover you will need to get the wheel itself turned down (ie clipped). The guys with the bigger stepped housings will just need to get the wheel turned and a new cover made. They will still have the 100mm+ exducer so while that rule will really not change much if anything.

I'll be the first to take constructive criticism and as such....

Well... per your suggestion, I went and did some reading. Still not 100% on the level with all this, but I believe I now understand why my statement was inaccurate.

My Source:

TurboByGarrett.com - Turbo Tech102

A 2.6" INDUCER is what the requirement of the class is currently. There is at this point however, no limitation on the Exducer size of the compressor wheel.

I apologize.. I did not take into account the fact that there is as of yet to be a direct correlation (Set Trim) between inducer and exducer size for the 2.6" class.

So to put a limitation on the Exducer size would be very difficult for the simple reason of you'd be limiting turbo charger design to an almost crippling degree.

No limit is what is really causing the gap in 2.6 now. It would not be "crippling".

Replies in Red

 

[Convicted1]

Good answers... I'm too tired at this point to ask more questions though.

I'll check back in tomorrow night.

I got that book ordered... Like I said... I'm not opposed to learning.

I guess the last question I have for the night is this...

Why go to all the trouble of machining a cover for a big compressor wheel to fit in the 2.6" class versus just running a turbo with the same wheel size and a properly matched inlet in the 2.8" class? The turbo would be more efficient with a properly matched inlet anyway!?

I guess I just don't really understand....

 

[JOHNBOY]

Good answers... I'm too tired at this point to ask more questions though.

I'll check back in tomorrow night.

I got that book ordered... Like I said... I'm not opposed to learning.

I guess the last question I have for the night is this...

Why go to all the trouble of machining a cover for a big compressor wheel to fit in the 2.6" class versus just running a turbo with the same wheel size and a properly matched inlet in the 2.8" class? The turbo would be more efficient with a properly matched inlet anyway!?

I guess I just don't really understand....

Because they like to win.

It does not effect things as much as you think. I have a 2.8 bushing for me 3.0 turbo. I lost less then 10hp with the bushing in on the dyno.

 

[Rods]

Yes and no. If the wheel must protude into the inducer bore you can still have the bigger turbos. Instead of just a stepped cover you will need to get the wheel itself turned down (ie clipped). The guys with the bigger stepped housings will just need to get the wheel turned and a new cover made. They will still have the 100mm+ exducer so while that rule will really not change much if anything.

So yr saying a 2.6 contoured will flow the same as 2.8 having the same exducer ?

 

[nwpadmax]

There's a lot of tech that needs to be better understood here.

Let's just say for the sake of discussion we're going to use a GT42 with the 75mm inducer and 102mm exducer.

You can step that cover to 66mm bore and "hide" the bigger wheel and it's for sure going to deliver more mass flow than a Sledpuller 66 with a native 66-ish bore.

If you are talking wheels with unaltered 66mm inducers, there is a tradeoff to be considered. With a very low trim, meaning 66mm inducer and a large exducer, these generally make more pressure ratio at the expense of mass flow rate. A high trim wheel with a 66mm inducer and a smaller exducer (than the above wheel) will tend to make more mass flow rate at the expense of pressure ratio.

So for example you can buy a box-stock GT42 and it comes in 53 trim. There are wheels with larger and smaller trim depending on what you're trying to accomplish and where your motor needs to run based on rpm, volumetric efficiency, fueling rate, single vs. twin, etc.

So I'm only covering a small part of turbo matching here but I hope you get the point that a "spec charger" is more of a fantasy thing because all of the motors run with different power bands. If someone tried to create a class like they have in SuperFarm, I wouldn't run it. Where you have more commonality in the engines, then a spec charger works.

And this is all just looking at the compressor side. You could write a book about what is happening on the turbine side too!

However, that all being said, if you limited the exducers of the comp wheels to 102mm or whatever, it really boxes in how much difference there will be in mass flow rate between trucks. And that's the probably the best shot at leveling the playing field as there is. You could also spec the turbine wheel, but then you would have to spec wastegates and VNTs, etc., and that's even more of a pain in the arse.

However, no one is going to do it because no one wants to tech it. So even though you and I totally agree on the proper vision for the class, I've become enough of a bitter old fart that I have to deal with what is, rather than what should be.

 

[SmokeShow]

Yes and no. If the wheel must protude into the inducer bore you can still have the bigger turbos. Instead of just a stepped cover you will need to get the wheel itself turned down (ie clipped). The guys with the bigger stepped housings will just need to get the wheel turned and a new cover made. They will still have the 100mm+ exducer so while that rule will really not change much if anything.

So yr saying a 2.6 contoured will flow the same as 2.8 having the same exducer ?

I don't mean to speak for Johnboy but I think he's saying the contoured wheels extended into the cover bore will make about the same as the turbos with stepped covers or bushings. Depending on how tight the step in the cover or the bushing is to the face of the comp wheel has everything to do with the abilities of the turbo with larger wheels. If the rules are going to allow bushings and/or stepped covers, they should at least have a statement about how close to the face of the wheel the step or bushing has to be. Scheids rules wouldn't cut it at all. Their bushing rule was a joke! There was awesome bushings made for that ruleset that would just about flow as good with or without the bushing. Sweet but the rules should be tighter than they were.

 

[ChevyDealer]

Jump up and down all you want, this is the entertainment business we're in. Don't be yelling at the other dancing monkeys. Yell at the guy who owns the circus if you think the circus sucks.

op:
Kinda like this thread.

 

[2000wvdodge]

id like to know what poor tech guy is gonna be dumb enough to be helping next year when 100+ trucks show up somewhere like ts and he has to be part of teching the exducer of a compressor wheel on that many trucks.

 

[nwpadmax]

id like to know what poor tech guy is gonna be dumb enough to be helping next year when 100+ trucks show up somewhere like ts and he has to be part of teching the exducer of a compressor wheel on that many trucks.

a) only tech the money trucks for picky turbo stuff.

b) make it mandatory that you must be able to pull your cover in 10 minutes or less, or forfeit your run. If you can pull at this level you should know how to run a wrench by now.

c) when a class gets this size, we need more techs.

 

[05smoker]

a) only tech the money trucks for picky turbo stuff.

b) make it mandatory that you must be able to pull your cover in 10 minutes or less, or forfeit your run. If you can pull at this level you should know how to run a wrench by now.

c) when a class gets this size, we need more techs.

Gonna be tough to tech that fast on a DMax. Except mine.:shake:

If they only tech the top 5 I shouldn't have to worry.LOL

 

[nwpadmax]

Gonna be tough to tech that fast on a DMax. Except mine.:shake:

If they only tech the top 5 I shouldn't have to worry.LOL

Any of the hi-po Dmaxes running a nice tall pedestal like an ATS, or other pedestal with a tall spacer block in it will be a 5-minute job.

If you use that stubby PPE pedestal and no spacer...yeah your life will be rough. Oh well....it's the drivers job to figure out.

If you can run in the top 5 and can't figure this out....hmmm...:doh: