1 2
coldiceEVO
coldiceEVO
4/15/22 2:02 p.m.

Hi, my first post here. I found it funny that tractors can cram ~300 psi(20atm) of boost to their engine.

Basically the limitation on engine should be the equivalent of tractor pulling and pikes peak mountain climbing unlimited/modified. Other races I've looked into so far either limit boost pressure(indycar), intake restriction(FSAE), or limit to single turbo/NA(scca prototype 1&2, dirt track), or a combination of them, from prestigious to grassroots. I don't know much about drag race categories or lessor known ones/race-whatever-ya-brung type of deal.

BlueInGreen - Jon
BlueInGreen - Jon UltraDork
4/15/22 2:08 p.m.

Time attack?

Captdownshift (Forum Supporter)
Captdownshift (Forum Supporter) GRM+ Memberand MegaDork
4/15/22 2:11 p.m.

Isle of Man

wearymicrobe
wearymicrobe PowerDork
4/15/22 2:56 p.m.

The only rational place is standing mile and salt flat,  bunch of Supra's allegedly in the works that do something around 60PSI that I have heard of being built. 300psi not a chance. 

coldiceEVO
coldiceEVO New Reader
4/15/22 3:09 p.m.

In reply to BlueInGreen - Jon :

Actually a good idea, gridlife has an unlimited category. and the search phrase gave me motorsportreg.com which helps me to find some local ones to think about.

coldiceEVO
coldiceEVO New Reader
4/15/22 3:23 p.m.

In reply to wearymicrobe :

As far as I know 60 PSIg is pretty much around the pressure ratio limit of a single stage of turbo for automobiles sizes. 300 psig isn't too far fetched for two stages.

Captdownshift (Forum Supporter)
Captdownshift (Forum Supporter) GRM+ Memberand MegaDork
4/15/22 3:32 p.m.

I can only imagine the IATs at that boost level...

wearymicrobe
wearymicrobe PowerDork
4/15/22 5:32 p.m.
coldiceEVO said:

In reply to wearymicrobe :

As far as I know 60 PSIg is pretty much around the pressure ratio limit of a single stage of turbo for automobiles sizes. 300 psig isn't too far fetched for two stages.

Making boost is easy, keeping it inside the block is not. Called a friend with a standing mile supra and asked him what he was pushing. A 60PSI he make ~1600hp at the wheel. he is digging up the dynosheet and sending me a photo. Its very tire limited even at around 30PSI so he said that they run different boost levels per gear. 

Robbie (Forum Supporter)
Robbie (Forum Supporter) GRM+ Memberand MegaDork
4/15/22 5:47 p.m.

Don't they fill the water jackets of tractor pull motors with stuff like concrete?

With 10 second runs, they don't need much cooling. I'd imagine the extra weight out front doesn't hurt either.

coldiceEVO
coldiceEVO New Reader
4/15/22 5:59 p.m.

In reply to Captdownshift (Forum Supporter) :

Diesel and alcohol engine aren't detonated limited, if that is a problem they can always do water injection to cool. Intercooler would also work but I think they are ruled out, ones that would work for 300 psi would definitely be thick and heavy. 

Captdownshift (Forum Supporter)
Captdownshift (Forum Supporter) GRM+ Memberand MegaDork
4/15/22 6:22 p.m.

In reply to coldiceEVO :

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

Sonic
Sonic UberDork
4/15/22 6:25 p.m.

Lemons would certainly entertain such foolishness, if run on pump gas or diesel.  

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
4/15/22 6:37 p.m.
Captdownshift (Forum Supporter) said:

I can only imagine the IATs at that boost level...

The beauty of twincharging is that it reduces detonation when you have, say, a turbo pushing 2:1 pressure ratio into a blower adding a 1.5:1 pressure ratio.  You get 30psi intake manifold pressure but only the exhaust manifold pressure for 15psi.  Helps scavenging immensely, no hot exhaust gases left over in the chamber to start the detonation train rolling.

I assume that vehicles like the Delta S4 bypassed the supercharger because with the fuels they used, detonation was not a problem anyway, so they had more to gain from effectively decoupling the blower than any theoretical combustion benefits.

WillG80
WillG80 GRM+ Memberand Reader
4/15/22 6:41 p.m.

Diesels usually have 6 head bolts per cylinder, up from the more traditional 4 on gasoline engines. That allows them to handle the extra compression and boost. It's one of the reasons the Ford 6.0 engines struggle with head gaskets, they only have 4 bolts per cylinder. 
 

I don't think it's realistic keeping a cylinder head attached to a gasoline engine at those boost levels. I'd be curious to see what 300psi translates to in cylinder pressure on some of these engines. 

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
4/15/22 6:43 p.m.
WillG80 said:

Diesels usually have 6 head bolts per cylinder, up from the more traditional 4 on gasoline engines. That allows them to handle the extra compression and boost. It's one of the reasons the Ford 6.0 engines struggle with head gaskets, they only have 4 bolts per cylinder. 
 

I don't think it's realistic keeping a cylinder head attached to a gasoline engine at those boost levels. I'd be curious to see what 300psi translates to in cylinder pressure on some of these engines. 

Usually the issue, even in Diesels, is keeping the deck attached to the main journals.

VolvoHeretic
VolvoHeretic GRM+ Memberand Reader
4/15/22 7:48 p.m.
coldiceEVO
coldiceEVO New Reader
4/15/22 8:23 p.m.

In reply to Sonic :

2 turbos(one much larger) quickly cut into the shoe string budget, nor would making the engine block a cooking grenade count as safety spending. 

coldiceEVO
coldiceEVO New Reader
4/15/22 8:49 p.m.

In reply to WillG80 :

Most likely would need a total different gasoline engine design from anything in the market today, the pressure requirement is one magnitude higher than usual, while gasoline are designed to exploit rev more than their diesel brother.

There won't be gasket issue if it is not there. Offenhauser engine cast the head and cylinder as one block, and the crankshaft and the web are beefy at the cost of more hassle to assemble. Otherwise more bolts are needed.

As far as my understanding on knock, as long as charge air temperature is within acceptable range, by means of water injection or intercooler, it should run just fine, plus the two compressors can each run at more efficient range than squeezing the max pressure ratio out of a single stage, so less heat to cool down.

Sonic
Sonic UberDork
4/15/22 8:51 p.m.

In reply to coldiceEVO :

Nobody will care as you are doing something ridiculous and are not going to win on laps, as long as you don't oil down half the track. 

dculberson
dculberson MegaDork
4/15/22 9:09 p.m.

UTCC (ultimate track car challenge)?

j_tso
j_tso GRM+ Memberand HalfDork
4/16/22 12:16 p.m.

The last compund turbo in racing I remember is the Mazda diesel engine in IMSA. It melted its pistons and still made less power (450) than its competition.

wspohn
wspohn SuperDork
4/16/22 1:07 p.m.

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

 

Ranger50
Ranger50 MegaDork
4/16/22 1:49 p.m.

In reply to Robbie (Forum Supporter) :

Normally they are solid billet at this level. If they have to run "gas", it's methanol.

coldiceEVO
coldiceEVO New Reader
4/16/22 4:52 p.m.

In reply to j_tso :

What are their competitors and category? Quick google showing me it was LMP2 and others are running with 4L+ of v8s against this 2.2L inline 4.

j_tso
j_tso GRM+ Memberand HalfDork
4/16/22 5:36 p.m.

In reply to coldiceEVO :

It was a transition period in 2014-2015 when American Le Mans Series merged with the Rolex Sportscar Series, so there were LMP2s competing with Daytona Prototypes. Most of the competition were ~600 hp V8s and turbo V6s.

I think Mazda was optimistic since in ALMS they competed with a 2.0T gasoline engine that made more power. However, that was a clean sheet race engine and the diesel was a modified production car block. They went back to the gasoline engine in 2016 and steadily improved it until they withdrew last year.

1 2
Our Preferred Partners
9cXQN62l5edN6a2dPVoqHIfkaysChQRIEAF6PrM0dRIqRbLuJabpoWnGKshRNIr6