What makes an engine able to make more power on pump gas?
09-03-2010, 03:52 PM
#61
TECH Fanatic
Thread Starter
iTrader: (5)
Join Date: Apr 2005
Location: Phoenix AZ
Posts: 1,005
Likes: 0
Received 0 Likes
on
0 Posts
Many of your are pointing to the block being an issue, and i agree to a point, but isn't the LSX or dart or any aftermarket iron block that we can get gonna be close to as strong as the 2jz? I understand the tearing itself apart issue. And that makes alot of sense. But cant the better casting and bolt patterns of the aftermarket blocks make up for this vs a stock 2jz? I know those engines were made by God and all but are they really godly?
As far as they heads I'm getting that the 4v heads they use are great. And that it allows for smaller lift since you have better flow. But doesn't the larger cylinders that we have afford us more room for our 2 valves that would then outflow a much smaller 4v engine?
As far as the E85 goes I hope that they have to use 93 octane gas. From what i understand the E85 isn't regulated to the extent that typical gasoline is and that can make from broad spectrum of quality and octane. So they could put some ringer E85 gas in and call it good to go. I just hope that isn't the case.
Thanks everyone for all your wisdom so far. Its been one of those questions that have been perplexing me for a long time.
John
As far as they heads I'm getting that the 4v heads they use are great. And that it allows for smaller lift since you have better flow. But doesn't the larger cylinders that we have afford us more room for our 2 valves that would then outflow a much smaller 4v engine?
As far as the E85 goes I hope that they have to use 93 octane gas. From what i understand the E85 isn't regulated to the extent that typical gasoline is and that can make from broad spectrum of quality and octane. So they could put some ringer E85 gas in and call it good to go. I just hope that isn't the case.
Thanks everyone for all your wisdom so far. Its been one of those questions that have been perplexing me for a long time.
John
09-03-2010, 05:15 PM
#62
the 2jz was designed for use with a turbo from the beginning. everything in the motor is built designed around use of turbo.
the heads,bore,cylinder sealing (flame propagation) stroke, deck thickness, heads, head gaskets, head bolts. . etc.
it also doesnt hurt that it came from the factory with premium parts and precision assembly and machining. even the block material was designed for its intended purpose.
the ls was designed originally as a n/a production motor.
it just so happens that it excels at what it does and seriously responds to most any mod to increase hp production.. with inline 2 valves and pushrods.
just so happens that it responds very well to positive manifold pressure. the ls properly built will perform without aid of any power adder.
engines designed around forced induction are nothing especial without the aid of there devices
the heads,bore,cylinder sealing (flame propagation) stroke, deck thickness, heads, head gaskets, head bolts. . etc.
it also doesnt hurt that it came from the factory with premium parts and precision assembly and machining. even the block material was designed for its intended purpose.
the ls was designed originally as a n/a production motor.
it just so happens that it excels at what it does and seriously responds to most any mod to increase hp production.. with inline 2 valves and pushrods.
just so happens that it responds very well to positive manifold pressure. the ls properly built will perform without aid of any power adder.
engines designed around forced induction are nothing especial without the aid of there devices
09-03-2010, 05:17 PM
#63
On The Tree
Join Date: Mar 2006
Posts: 150
Likes: 0
Received 0 Likes
on
0 Posts
Lets back up here and look at the facts.
Take any of the in line 4’s or 6’s making 1000 hp
and put either one in the same race car as a 1000 hp 350-400 +
cid V8 at the same weight and the V8 will out run them every time.
Look at a Mazda rotary motor, they are some of them running 6’s.
But it’s in a beer can.
Put that 1600 hp 2JZ in your 3800 lb F-body and drive it around on the street
and you will get board with it real fast.
That thing would be the most gutless turd you ever drive.
A 16 year old kid with a 50 shot on a 100,000 mile Civic
would hand you your *** stop light to stop light.
A 9:1 427 with a set of heads that flow in the mid 350’s
will make 600+ on the motor alone.
10-12 psi of boost out or a properly sized turbo will make a 1000 hp
on 93 pump any day and have enough toque to pull tree stumps to boot.
Take any of the in line 4’s or 6’s making 1000 hp
and put either one in the same race car as a 1000 hp 350-400 +
cid V8 at the same weight and the V8 will out run them every time.
Look at a Mazda rotary motor, they are some of them running 6’s.
But it’s in a beer can.
Put that 1600 hp 2JZ in your 3800 lb F-body and drive it around on the street
and you will get board with it real fast.
That thing would be the most gutless turd you ever drive.
A 16 year old kid with a 50 shot on a 100,000 mile Civic
would hand you your *** stop light to stop light.
A 9:1 427 with a set of heads that flow in the mid 350’s
will make 600+ on the motor alone.
10-12 psi of boost out or a properly sized turbo will make a 1000 hp
on 93 pump any day and have enough toque to pull tree stumps to boot.
09-03-2010, 08:14 PM
#64
FWIW, a stock 2jzGTE will out flow a stock LS1 below .400 lift. After that it stalls at about 228cfm. And thats with a 3.39 bore. From there the LS1 keeps breathing deeper. Now I am going to go cry in the shower because I did research on a 2jz. Thanks guys.
09-04-2010, 01:26 AM
#65
Keep in mind piston speed vs flame front speed. Engine 1 making 600 hp @ 6000 rpm will have a much higher cylinder pressures (limits fuel). I may be wrong but I believe the flame speed of pump gas (93 octane) burns at about the same rate the piston is traveling around 4000-5000 rpm. While engine 2 could make 600 hp @ 10,000 rpm but have much less cylinder pressure than engine 1. Cylinder head shape, size, valves per cylinder, compression and what not are all factors but the main thing to keep in mind is piston speed. The power stroke is not where an engine is under the most stress, peak stress loads actually occur at the top and bottom of the stroke from sudden acceleration direction change. More rpm adds way more stress to try and maintain proper clamping force on the rod bolts versus adding boost. This is why stock engines with a proper tune can run on a decent amount of boost for a long time, but take your same stock engine and try to turn it an extra 2000 rpm.
Last edited by Nitroused383; 09-04-2010 at 01:57 AM.
09-21-2010, 06:53 AM
#66
TECH Apprentice
Join Date: Jan 2008
Location: Gladstone, Queensland, Australia
Posts: 366
Likes: 0
Received 0 Likes
on
0 Posts
In a word, "yes".
Stock Lancer EVO's (4v pentroof) run 20+ psi stock (with plenty of safety margin) and 23+ psi slightly tweaked on pump gas. Plenty of Sea-Doo 4-tec SC (4v pentroof) run up to 25 psi on pump gas (in a very harsh high-load environment) reliably.
2v wedge chambers can't go anywhere near those numbers. I'm no tuner, but I've found that 18 psi on a 2v wedge design even at 8.5/1 compression is on a wing and a prayer, not to mention requires a bunch of power-robbing timing retard. Get a bad tank of gas, hot day outside, fuel pump bobble, ignition timing slip, etc. and the motor is toast.
Stock Lancer EVO's (4v pentroof) run 20+ psi stock (with plenty of safety margin) and 23+ psi slightly tweaked on pump gas. Plenty of Sea-Doo 4-tec SC (4v pentroof) run up to 25 psi on pump gas (in a very harsh high-load environment) reliably.
2v wedge chambers can't go anywhere near those numbers. I'm no tuner, but I've found that 18 psi on a 2v wedge design even at 8.5/1 compression is on a wing and a prayer, not to mention requires a bunch of power-robbing timing retard. Get a bad tank of gas, hot day outside, fuel pump bobble, ignition timing slip, etc. and the motor is toast.
09-21-2010, 12:15 PM
#67
TECH Veteran
Join Date: Aug 2002
Location: Hartsdale, NY
Posts: 4,055
Likes: 0
Received 0 Likes
on
0 Posts
The new Dodge Hemi engines do not have a Hemi-domed cylinder head; right? I heard that hemi heads make great power as they breathe easy but it is not possible for a modern hemi to produce low emissions numbers that are required by today's emissions laws.
09-21-2010, 02:14 PM
#68
Teching In
Join Date: Jun 2009
Posts: 24
Likes: 0
Received 0 Likes
on
0 Posts
I dont really understand the debate, but if it is a straight six vs. v8 - v8 stomps... no debate about it. There are POS ls motors for boost just like there are POS toyota v6's for boost - comparing a non-performance engine to a factory turbo is a waste of life.
But if you want to know which is king, look all over this board. For money, reliability, performance and all the above a 2jz is a POS.
Dont get it wrong, the supra six is badass for what it is. Factory to Factory yeah sure its better, its also twice the price and has fairly turddy performance when stock. Then add in about 30-100gs in aftermarket and you get the engine you see above. but in the hypothetical comparison your just blowing smoke up your *** to say it beats LSX stuff. If the 2j makes 1600 hp an LSX or big block will make 2000+ for less money and withstand years of abuse.
And just to throw my hypothetical nonsense around... I dont see any straight sixs in top fuel.... No, just big block hemis making 8000+ hp.
But if you want to know which is king, look all over this board. For money, reliability, performance and all the above a 2jz is a POS.
Dont get it wrong, the supra six is badass for what it is. Factory to Factory yeah sure its better, its also twice the price and has fairly turddy performance when stock. Then add in about 30-100gs in aftermarket and you get the engine you see above. but in the hypothetical comparison your just blowing smoke up your *** to say it beats LSX stuff. If the 2j makes 1600 hp an LSX or big block will make 2000+ for less money and withstand years of abuse.
And just to throw my hypothetical nonsense around... I dont see any straight sixs in top fuel.... No, just big block hemis making 8000+ hp.
09-21-2010, 02:42 PM
#69
Cliff's notes:
Well, it started with me stating that we are stuck at 16-18 psi because of the wedge chamber. Someone else pointed out imports running low 20's. Then a debate insued about 4v versus 2v chambers and their relative resistance to detonation. Some people blurred the issue by talking about small-displacement import engines, rather than the specific chamber design.
Ideally, you would have a large-displacement v-8 with DOHC and 4v/cyl, FI, and intercooling. This would represent the best aspects from both sides of the pond. I posted a link to a good factory-production example that makes 1350 hp on pump plus has a warranty.
Well, it started with me stating that we are stuck at 16-18 psi because of the wedge chamber. Someone else pointed out imports running low 20's. Then a debate insued about 4v versus 2v chambers and their relative resistance to detonation. Some people blurred the issue by talking about small-displacement import engines, rather than the specific chamber design.
Ideally, you would have a large-displacement v-8 with DOHC and 4v/cyl, FI, and intercooling. This would represent the best aspects from both sides of the pond. I posted a link to a good factory-production example that makes 1350 hp on pump plus has a warranty.
