1 2
AnthonyGS (Forum Supporter)
AnthonyGS (Forum Supporter) UltraDork
4/16/22 5:46 p.m.
Captdownshift (Forum Supporter) said:

In reply to coldiceEVO :

 air temperature increases exponentially with the amount that it's compressed. You'd likely need to be running nitro methane 

Linearly.  Charles' and Boyle's gas laws. 

 

BMW 1.5L 4 cylinder 1350 hp... lots o boost.  Drag racing, you can run as much boost as you can build your engine to withstand.  F1 outlawed these engines after a lot of brutal crashes. 

 

https://historicmotorsportcentral.com/2014/04/22/raw-power-the-bmw-m1213-f1-engine/

 

coldiceEVO
coldiceEVO New Reader
4/16/22 6:37 p.m.

In reply to AnthonyGS (Forum Supporter) :

Engines like these makes me question how stagnate everything is.

AnthonyGS (Forum Supporter)
AnthonyGS (Forum Supporter) UltraDork
4/16/22 8:16 p.m.
coldiceEVO said:

In reply to AnthonyGS (Forum Supporter) :

Engines like these makes me question how stagnate everything is.

It was an amazing engine in its day.  It really showed what boost could do. If I win the lotto.....

A 401 CJ
A 401 CJ SuperDork
4/16/22 9:01 p.m.
wspohn said:

1957 - MG EX181 - 32 psi boost, 1489 cc engine, 245 mph at Bonneville.

1955 BRM 1500 cc V16 engine boosted at  80 psi by two stage blower 600 bhp at 12,000 rpm.

Been there, done that.  The latter sounded like a demented chain saw and scared both Fangio and Moss.

This is some other idiot taking the car out in the rain(!)

 

https://www.youtube.com/watch?v=umO3iqac_4c

 

WOW!  That just made me feel a little bit more alive.  Thanks for that.

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
4/17/22 8:34 a.m.
coldiceEVO said:

In reply to AnthonyGS (Forum Supporter) :

Engines like these makes me question how stagnate everything is.

Mostly it showed how bad the engineering was in the 1960s.

 

BMW used stock blocks that were engineered back then.  If a 90hp engine has a block capable of handling 1500hp, some engineer somewhere really screwed up.

 

Back to compound turbos, the problem with them is they amplify the poor response of a turbo engine.  That is why you only see them in places where response is unimportant: tractor pulling and OTR Diesels.  I'd also like to say that one of the Powerstrokes had a compound turbo setup but you don't see very many Diesel trucks around here so I couldn't tell ya.

AnthonyGS (Forum Supporter)
AnthonyGS (Forum Supporter) UltraDork
4/17/22 9:11 a.m.

In reply to Pete. (l33t FS) :

The 3rd gen Rex had a compound turbo or at least a complex dual turbo setup.  It's been used outside tractor pulls.

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
4/17/22 9:16 a.m.

In reply to AnthonyGS (Forum Supporter) :

I thought all Rexes had high revving naturally aspirated engines to meet the 65hp limit, not turbocharging.

preach (dudeist priest)
preach (dudeist priest) Dork
4/17/22 9:22 a.m.

300psi...not sure about that.

3000hp Cummins (but it was the NO2 that blew it:

80psi to a Honda block, can't remember series:

My BH puckers hard when I am at 25psi.

 

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
4/17/22 9:29 a.m.

In reply to preach (dudeist priest) :

In the early 1980s when Hugh MacInnes wrote his book Turbocharging, he wrote about tractor pullers running three stage compound turbos to get over 200psig.  (I guess the distinction between psig and psia is academic at these pressure levels)  I can see pressure going into the 300psi range after forty years.

java230
java230 PowerDork
4/17/22 10:40 a.m.
Pete. (l33t FS) said:
coldiceEVO said:

In reply to AnthonyGS (Forum Supporter) :

Engines like these makes me question how stagnate everything is.

Mostly it showed how bad the engineering was in the 1960s.

 

BMW used stock blocks that were engineered back then.  If a 90hp engine has a block capable of handling 1500hp, some engineer somewhere really screwed up.

 

Back to compound turbos, the problem with them is they amplify the poor response of a turbo engine.  That is why you only see them in places where response is unimportant: tractor pulling and OTR Diesels.  I'd also like to say that one of the Powerstrokes had a compound turbo setup but you don't see very many Diesel trucks around here so I couldn't tell ya.

6.4 powerstroke is compound. I have one.

As to compound, adds heat for sure, also drive pressures get much higher than a single. 

wspohn
wspohn SuperDork
4/17/22 11:50 a.m.

I also loved the Zakspeed Capris in the 70s when they beat the Porsche 935s. The later larger displacement cars were interesting but I liked the 1.4 liter versions that got 495 bhp . (They got 600 bhp out of the 1.7 liter version)

 

https://www.classicfordmag.co.uk/features/fords-forgotten-history-zakspeed-capri-story/

coldiceEVO
coldiceEVO New Reader
4/17/22 6:31 p.m.

In reply to Pete. (l33t FS) :

I won't really say bad, in fact the peak of engineering, for leaving plenty of margin for longevity, safety and future of modification. The longest plank of a bucket seems like a waste, but in the era of constant upgrading and exploring, one less part to be redraw when necessary technology came to lengthen the shortest plank saves valuable work and material. One can not tweak an even barrel, as every plank needs to be thrown out. And throwing things away summarized the today's view on immediate return, abundance of work, product and materials, ended up wasting time running in circle.

The problem of the ship of Theseus would only arrive when the last major original plank is about to be removed.

btw the CR dropped from 8-9.5 of m10 to 7.5, the insane peak power is certainly gained from lowered CR, doubled rev, and added boost to keep peak temp and pressure at bay. They must have swapped out 50% of the part, especially moving ones to accommodate for the changes. and a lot of repairing and care is given to the engine per operating time than their commercial counterparts. 

Another way to think about is that the stress of the engine may have many components, temperature, pressure and speed, speed squared all poses stresses in different direction of stress, to accommodate the largest one means over build for other stresses. Gun barrels doesn't need to be that thick, but still made to be thick to keep barrel from whipping and warping that affects accuracy than to contain pressure.

alfadriver
alfadriver MegaDork
4/17/22 6:53 p.m.

In reply to coldiceEVO :

Do you really think the 60's were the peak of engineering?  Really?  

That there was a 1000 hp 5.0l flat 12 designed by Porsche was some kind of peak?  When we have 1000hp F1 powertrains that use a fraction of the fuel, weigh less, and are way more reliable?

The issue with unlimited boost thinking is that almost every single racing series in the world has a power limit on it- most of then have had it for many decades.  And engines are designed around those limits.  So you can't put 50psi of boost on an engine designed around a N/A concept.  If it could, it would weigh too much, take too much time to warm up, and cost more than it needs to be.

coldiceEVO
coldiceEVO New Reader
4/17/22 9:20 p.m.

In reply to alfadriver :

Did we even bring up the porsche engine? As for weight, 140ish kg is about the standard since thirties. And despite the advancement in structure integrity, rubber, and aerodynamics they are still on the same old power limit for so many decades?

Rules are used to artificially rule things out, they are poor guidelines for natural growth of individual's ability to do things they see fit and often a result of governing body politics. Revs, boost, weight, tweek a little and different teams' competitiveness rise and sink, or simply eligibility in no time, thus it can be weaponized solely by influence. Only team that are the most formulaic to the formula become successful. Characters lost, corporate rises, viewership dwindles despite the cost are flying, further spirals into more regulation to favor the money until no soul is left to cannibalize. 

Fitting NA concept to a single turbo requires minor adjustment to the NA parts. Change the piston crown can change the CR, which reduces the peak pressure and temperature back.

wvumtnbkr
wvumtnbkr PowerDork
4/17/22 9:36 p.m.
Pete. (l33t FS) said:

In reply to AnthonyGS (Forum Supporter) :

I thought all Rexes had high revving naturally aspirated engines to meet the 65hp limit, not turbocharging.

Pretty sure he meant rx7s.

alfadriver
alfadriver MegaDork
4/18/22 8:33 a.m.

In reply to coldiceEVO :

Ok, well good luck in your search, then.  I'm sure your minor adjustments won't leave you with blocks broken in half from over pressure.

j_tso
j_tso HalfDork
4/18/22 9:00 a.m.
AnthonyGS (Forum Supporter) said:

In reply to Pete. (l33t FS) :

The 3rd gen Rex had a compound turbo or at least a complex dual turbo setup.  It's been used outside tractor pulls.

The 3rd gen RX-7 had sequential twin turbos. Contrary to what reviewers say, they are equal size.

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
4/18/22 9:58 a.m.

In reply to j_tso :

I haven't seen that, but I wonder if there was some early confusion because the twin turbo Cosmo 13B came first, and it did have a smaller primary turbo.  You know how press releases and media packets get their info jumbled sometimes.

 

Either way, it is turbos in parallel not series.

preach (dudeist priest)
preach (dudeist priest) Dork
4/18/22 3:51 p.m.

How about my buddies turbo and supercharged 5.3 LS in a '49 Plymouth gasser. 

Gentlemen, I give you Jolene:

 

 

AnthonyGS (Forum Supporter)
AnthonyGS (Forum Supporter) UltraDork
4/18/22 5:37 p.m.

In reply to Pete. (l33t FS) :

I'm not sure if I remember exactly how the RX7 setup worked and I don't want to go digging for the RX7 design book during a move.  I do remember one turbo coming on at low rpm and then the second at higher rpm.  The exact plumbing, not really sure.  
 

I also know that temp goes up linearly with boost.  Convert to absolute temperature and boost pressure and temp are linear.  

Paul_VR6 (Forum Supporter)
Paul_VR6 (Forum Supporter) SuperDork
4/19/22 8:59 a.m.

Starting to see compound setups come around more in import racing. Usually in little rules classes, or ones where nitrous doesn't make sense or can't be used easily. 

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
4/19/22 12:02 p.m.

In reply to AnthonyGS (Forum Supporter) :

All exhaust flow was routed through the primary turbo, with the secondary turbo shut to prevent the boost from blowing backwards through its compressor.  Then it would prespool the secondary turbo (compressor routed to itself) and finally gate the secondary turbo into the system.  Thus the 10-8-10 boost pattern.

In the late 90s, the Mailing List had all sorts of info on what each solenoid did and what each vacuum restrictor did and what changes did what.  

1 2
Our Preferred Partners
SVKUDMnttesxdjb62AOuiNvY7EVCRbEL2TqgGRs9FE1B1SFTTAbA3Nk4knNs9OiB