even so I think we are all very proud that your 500+hp highly modified stroker motor can beat a little stock to mildy modded nissan. that is quite a task there

but one thing I am curious about

you said posting while you where drunk (which makes everything ok now that it has been explained) but whats up with you taking some guy and running him into the guard rail and braggin about it like it was something cool to do

 

hp is related to torque

if there was no torque there would be no hp

also hp does help with torque production through gearing. why do you think a lot of racers have motors that rev to the moon and back?

it allows for more gear which allows for more acceleration



but as far as pushing 285hp out of a motor like that ISN"T easy
takes a lot of work but it can be done for an N/A car
but it is tuning up the ***
real tuning as in getting parts matched right tweaking something a little here, take a little metal out of this port
not just adjusting the fuel/air/timing and calling it good

but as far as a street version I don't know
kinda doubt it unless he is talking s2000motor but those things already are fairly tweaked though sure you could get a little more out of them

 

was dyno
saying around cause I can't remember the exhuast number
just know it was 20 something and 30 something

but it is boosted

still import which so it is lumped into your catagory of "imports"
but the boost makes quite the difference in howm ods work

 

he was being an ******* in traffic.....then after cutting me off several times and still ending up behind me,

he decided that he would try to pass me on the right at a lane drop......apparently he grossly overestimated how fast his car was, because he didnt make it past the rear wheel before the guard rail.....

he apparently also falsely assumed that i would swerve my 26,000 gmc topkick out of his way, so he could ceonveniently pass me.....while i put the rest of the traffic on the highway at risk

you dont swerve around on the highway in a truck, it causes more problems than it will ever solve.

that sh*t snake got what he deserved...i really wish i had my digital camera for that

so ya, thats pretty cool in my book....hes lucky he didnt get knocked around for his troubles too

 

but are they even streetable?

Most of the cars in RACE curcuits that are hondas (if not all) are all stripped down, with roll cages, and are not street legal cause the compression ratio is so high they need race fuel. whats the average compression ratio on a N/A 4 cylinder honda motor?

he says 11 is high....and thats what he says theyd be running this at.

And even though they have high HP numbers on motor alone, does that necesarily mean that they have a very low 1/4 time?

 

the honda motors that N/A are pushing 285 hp
not at all
the only way I MIGHT be able to see it is with the s2000

other then that I really doubt it
also those N/A motors pushing 285 hp are full on race cars most the time pushing into the 10's if not 11's last I checked

if this guy was to do it in a street combo I would be shocked unless as I said by some freak chance he was able to do it to an s2000 motor but then again those things are fairly well tweaked as is so doubt much more then maybe 250-260 AT MOST would be pulled out of one

as far as compression
most honda motors (least the higher end ones for that type of car SI, GSR, type-r, and such) use around 11:1 stock

11:1 is what they use in the ls1/6 also isn't it?
actually don't quite a few cars now use 11:1 so I would call it that high
and I have seen a motor running over 12:1 on 87 octane before also
it is just all in how the motor is tuned and what parts you use

but I could easily see a honda running on 11:1 without any real problems as long as you use prem gas so I wouldn't worry about that

but 285 streetable hp out of a 4 banger
either needs boost, or nitrous I would say
other then that you are going to have too much work and time into a car that prolly isn't going to get it

 

see that was my largest question. Streetability, and friggin flow man. How the hell could that little four banger suck in enough air tp be pushin out that much without forced induction. I hear its possible, but how? the VTEC unit does help the way the car runs in the higher RPM's, but I still have a VERY hard time believing it.

The cost would be outragous, I would think the compression ratio would have to be HIGH (like 15 or soemthin) and race fuel.

just my tohughts....thanks!

 

good thing about DOHC motors is that they bring in two times as much air, in effect doubling the cubic inches of the motor. VVT is a great technology for cars like that need to worry about economy. I think VTEC and VVT is today's modern vaccum secondary.... just a thought... i am in no way backing up imports.

 

as bigal said VVTi and VTEC both help a lot to bring in more air
mainly by allowing a small street cam for daily driving use
then when the rpms go up
now they are running on some HUGE cam that might not even work for any other type of driving

that mixed with very good heads
and intake system they can flow fairly well

as far as how it is built though
have read a mag article that was about one of the fastest FWD N/A "monsters" in the pro drag using a 4 wanger
he only put out 285hp and used something like 15:1 compression other then that know very little other then it cost I think about 15k to put together

also with compression
if you run a little peanut cam
you might be stuck with 9.5:1 comression
step up to a WILD cam
you know 260/260* and .525/.525" lift
that compression amount that where once able to run might now go up to 11.1 or a little more maybe
put iron heads on max compression drops
put alum heads on compression can go up
cooler thermostat compression can go up (but you only want to go so low with this)
fuel injectors emty inside the head should help compression a little better
better head designs allow for more compression (read above 12.3:1 compression on 87 octane
all depends on how you build the motor
can't just live by the oh 11:1 to one is too high for street use
cause it all is how you build it

but I seriously doubt he is going to get that streetable out of a 4 wanger N/A



another thing
just to reread your very first post on this thread
as far as torque and getting off the line
just cause you have more torque doesn't mean your going to get off the line faster
a lot of the reasons domestics get off the line better
is torque is moved a little lower in the rpm range so it is easier to launch
ie. no revving up to 3000rpms which if you just dump shocks the tires a lot more and causes traction loss so it takes more skill
FWD is a bitch to launch also which is something else a lot of imports have against it
and look at tire width between imports and domestics
205-225 are healthy tires for imports
most domestics seem to swap for 255-275 width tires making for more grab
plus generally better suspension for launching goes to domestics as well

and see a lot of cars with torque in the higher rpm range use more gear
which in effect puts them in the power band fairly quick

 

hey hey dont bad mouth the z06 its GM too if anything badmouth the viper the z06 performs very close to as well and is half the money

 

rx7,

i believe the ls1's are around 10.5:1 compression.....

my engine is 11.5:1 and it runs fine on pump gas though

besides, vvt and such is old hat now.....in just a few years electronicly actuated valve trains will become mainstream, and cams will be a thing of the past all together

 

*
LS1 is 10.1:1 Premium gas

LS6 is 10.5:1 Premium Gas

Trailblazer 4.2 DOHC Inline 6 10:1 87 octane

My camaro's 305 10:1 premium gas

Octane requirements are based upon combustion chamber design as well as compression ratio.



*I dunno, thought I'd throw that in. May or may not have anything to do with the above BS. I didn't read it!

 

.....and timing, and cam specs, etc, etc.....its really hard to go buy compression ratio alone...

but anything over 12.0 is usually out of pump gas territory

 

sorry my bad

but I know have seen cars out there with 11:1 stock ratio

just having a hard time recalling exactly what they are

but you guys are right MOST the time anything over 12:1 is not pump gas but it can be done and a lot of it has to do with MANY factors
just many and most don't have the time/effort/money to make it work

and tom are you calling syaing I am full of BS

 

The old Jaguar V12 had 11.5:1 on premium fuel. It was due to cylinder head design. the last cars that engine went into were the XJS and the XJ12. It first came in the E type at 5.3 liters. In the 90s it came in 6.0 liter form. Great motor!

RX7...full of BS? No, maybe only half full!

 

dont forget the porche they ran obscenely high compression with turbos STOCK!

 

your going to hurt my feelings there


or take a look at the s2000
11:1 compression stock
plus people throw superchargers on there with 6 pounds of boost and if tuned right do not have detonation problems
but yet you will here many say at 11:1 there is no way what so ever to run boost

 

DOHC motors do not bring in 2 times as much air.
In order to fit 2 intake valves where one used to go, they have to be smaller, then the valves shroud each other making them flow even less.
However, you still get a gain. A better side to it is that you can design a more efficient combustion chamber so you can get away with running higher compression on lower octane fuel.

I thought the Jags started out as 12.5:1 compression engines, and dropped the compression to 11.5 then to 11:1 for emissions reasons.
They also used cheap gas, not premium.

 

ok, not exactly twice as much, but a whole heck of a lot more air then a SOHC version does. It in effect increases the cubic inches... not physicly, but by sucking in more air per cubic inch. DOHC cam heads are very efficient as they are hemispherical in shape. the "Hemi" chamber is a VERY efficient design.

 

Hey I got an idea....my 583cc Rotax snowmobile 2 stroke has some form of variable valve timing (they call it RAVE), and puts out over 100 hp, now if you somehow hooked up say 6 of these together and put them in a car, youd theoretically be putting out over 600 hp out of a 3.5L motor I bet that would be fun to drive wonder why they havn't thought of that yet?

 

beware of misinformation. i dont care how many valves a motor has, your not getting very far over 100% VE at any point in the RPM range without forced induction.

and most stock V8's are nearly 85% VE somwhere in the Rpm range... which means those DOHC maybe MAX 95% VE in stock trim... thats only 10% more air intake, not 100% more. it may hang on to the VE a little longer and higher... but the air intake is only a marginal difference, without boost.

and just to throw this in, since torque is directly related to cylinder pressure, or air intake, and air intake is directly related to engine size, an engine size and VE of that motor can give you a rough estimate of torque production... then from that you take RPM and do the math; Torque X RPM / (33,000 / 2 * 3.14) gives you a rough horsepower figure... which means the same math for a 350 applies to a 2.0 liter motor, torque vs VE wise, minus efficiency weight and pumping loss....

lets try it out. 2 Liter motor, about 150 cubic inches. at 100% VE a typical 350 makes about 420-440 ft.lbs of torque. cut it in half? 210-220 Ft.Lbs of torque (175 Cubes) so roughly 180-200 ft.lbs of torque for our 2 liter motor. but guess what? have a hard time getting 100% VE out of one of them in stock trim, so lets knock off 10%.... oh look 160-140 Ft.Lbs of torque. now subtract drivetrain loss.... another 8-10% for a FWD car. oh look, 140-160 Ft. Lbs of torque out of the 2 liter.

Now do some checking around. how much torque do most 2 liter motors put to the ground in stock trim with DOHC? oh look, our math was perfect. now do the RPM thing...

33,000 / 2 * 3.14 = 5252

torque (140) X rpm (7200) / 5252 = 191 horsepower @ 7200 RPM. So how far off am i from actual FWHP on a stock DOHC 2 liter motor? Id be willing to be not that far at all. give or take drivetrain %, give or take weight and frictional losses, i would be im within 20-30 horsepower of the actual thing.

Oh ya, one MORE thing. the same can be done with a boosted motor. lets take that 2 liter again, and some extra simple math you learned in high school. lets say we have that motor with 10 PSI of boost. simple now follow: what % is 10 of 14.7 ?
68%
now whats 68% of 191 horsepower? 129!
so whats 129 + 191 = 320, now since we are dealing with boost we need to subtract about 10-20% because of the heat introduced when air is compressed... lets say its intercooled.... take out about 15%.... whats 15% OF 320?
48! whats 320 - 48 = ?


272 horsepower from a 2 liter @ 7200 rpms with 10 PSI of intercooled boost and a 90%VE ... ballpark, of course, since this was done with alot of theoretical numbers... but i bet im close. in a light car this is good for high 12's, low 13's. so tell me what are most 2 liter cars with 10 psi of boost running? low 13's high 12's, perhaps?

 

few problems with some of the things you said
first you said something about 420-440lbslbs/tq out of a v8 right
which by your own admission the pushrod v8's don't generally produce very good VE%
but yet you are giving the imported motor less VE% then a pushrod v8

also aren't most typical 350's more in the 300lb/ft range?

second you talk about drivetrain loss
but with this are you taking into account the gearing as well?
ie
100lb/ft motor runs through a direct drive 4:1 axle
so it might dyno at maybe 90lbs/torque being the axle ratio is factored in to produce numbers showing drivetrain loss
when in all reality it might be making closer to 386lb/ft (400lbs/ft in an ideal world) because of that gearing

that's one thing about imports granted most the time they don't put out huge torque numbers on the motor itself
but most also use 4.1+ gearing which helps create torque at the wheels themself. that is partly why hp is a better factor in how fast a car would be. cause hp is a multiple of torque and higher rpms allow for more gear.
the motor is almost always producing MORE torque at the wheels then what a flywheel dyno would show



also how do you have 10psi of boost with only a 10% VE?

 

I stand corrected, Jag V12s had 12.5:1 in 1981. later it was reduced to 11.5:1 and then again to 11:1. As for the gas, it looks like Jag recommended regular and then later required premium for no apparent reason.

12.5:1, even more amazing. I read also that 14:1 prototypes were running around before the 12.5 was decided upon!

 

[QUOTE]Originally posted by rx7speed
<b> few problems with some of the things you said
first you said something about 420-440lbslbs/tq out of a v8 right
which by your own admission the pushrod v8's don't generally produce very good VE%
but yet you are giving the imported motor less VE% then a pushrod v8
</b> i used the V8@ 100% VE to keep numbers matching. comparing a 4cylinder @ 100+% under boost and a V8 at 75%VE isnt a very good way to compare numbers. by using 100%VE i can basically figure out how many "liters" the boost adds to the 4 cylinder motor... so when i subtract the VE from the 350 motor we can see just how much more power the 4 cylinder makes over 100%. also when did i say a 4 cylinder motor makes less VE? forget VE. in fact forget all the math. the question was never "is my math right" the question is am i even close? was i right baout the boost VS engine size VS horsepower? dont evade.<b>

also aren't most typical 350's more in the 300lb/ft range?
</b>
a stock 350 can make well over 300 Ft.Lbs, in fact that are almost all torque in stock trim. doesnt a stock TPI motor make like 340 ft.lbs? doesnt a stock pre-75 350 make almost 370 ft.Lbs of peak torque? <b>
second you talk about drivetrain loss
but with this are you taking into account the gearing as well?
ie
100lb/ft motor runs through a direct drive 4:1 axle
so it might dyno at maybe 90lbs/torque being the axle ratio is factored in to produce numbers showing drivetrain loss
when in all reality it might be making closer to 386lb/ft (400lbs/ft in an ideal world) because of that gearing
</b>
you cant factor in gearings because it plays no part in drivetrain loss whatsoever. frictional loss maybe, but thats only 1-2% anyways... and on top of that, extra gearing does not increase horsepower, and therefore does not increase torque. sure it may increase the speed the engine accelerates and give the motor more leverage (torque = force X length) on the ground, but it doesnt actually "add" torque, it just speeds up the rate at which the motor can make power. <b>

that's one thing about imports granted most the time they don't put out huge torque numbers on the motor itself
but most also use 4.1+ gearing which helps create torque at the wheels themself. that is partly why hp is a better factor in how fast a car would be. cause hp is a multiple of torque and higher rpms allow for more gear.
</b>
one again, gearing has no affect on horsepower at all. you increase the length which increases the "theoretical torque" but at the same time with a change in length you change the distance travelled, which means horsepower stays the same.
<b>

the motor is almost always producing MORE torque at the wheels then what a flywheel dyno would show
</b>
if that was the case then it would make more horsepower at the wheels also, which is NEVER the case. thats a really bass ackwards way of looking at it. <b>


also how do you have 10psi of boost with only a 10% VE? </b>

when did i say that? are you smoking stuff again?

 

I'm about to go to bed, so I don't feel the inclination for an exceptionally lengthy reply...however I must make a couple of quick comments:

AGREED!

A 2.0L is 122 cubic inches, not about 150. A nonturbo 2.0L generally does NOT make 180-200 ft lbs of torque, or even 140-160 ft. lbs after taking drivetrain losses into account. It's possible, but certainly not typical of all stock 2.0s.

There are too many variables at play to make this sort of blanket statement, such as compression ratio, head design, cam(s), etc. etc. etc. Even the DSM 1st gen 2.0 turbo that I'm going to assume that you are familiar with only makes 203 ft. lbs of torque in stock trim.

So you are assuming that the 2.0L in nonturbo trim is making 191 hp and then you are making an additional 129 hp from 10 lbs of boost and then you are knocking off 15% for the heat added through compressing the air due to an imperfect intercooling. OK.

Here's my major gripe here...at no point in any of this post did you mention a compressor map. A compressor map is an essential component in calculating power potential vs. boost for a given turbo. A T25 @ 10 psi is going to flow less air than a 14B @ 10 psi, and a 14B at 10 psi is going to flow less air than a 16G @ 10 psi (etc.). My point is that 10 lbs of boost is not going to give you the same amount of airflow from every turbo, and every engine is not going to be able to use that air the same way.

Secondly, the compression ratio necessary to make 191 naturally aspirated horsepower is not going to be very friendly for an additional 129 hp from 10 lbs of boost on top of it without great tuning and an awesome intercooler. This is certainly possible, but it's far from the standard.

A stock 1st gen DSM with a turbo 2.0 at 11 lbs of boost makes just 190-195 hp (FWD vs AWD, respectively). A stock 2nd gen DSM with a turbo 2.0 at 14 lbs of boost makes 210 hp. A stock Neon SRT-4 with a turbo 2.0 at (approximately) 15 lbs of boost, the biggest turbo of the bunch AND a front mount intercooler makes approximately 240 hp (since they are underrated, this value is argueable). I doubt that you could muster 272 hp from a T25 at 20 lbs of boost with race gas, since they usually peter out above 250 hp (2nd gen turbo DSMers, please feel free to correct me if I'm wrong here).

While none of these cars are "lightweight" in the sense of a CRX, they aren't tanks, either (except for the AWD models which are over 3,000 lbs). These cars range from high 13s to low 15s stock.

There are many other factors which influence the power potential of turbocharged engines. I am about to go to bed, but I refer you to MAXIMUM BOOST by Corky Bell. There are two great chapters that will take you step-by-step through the calculations which will help you choose the best turbo to get the desired level of power from a given engine.

 

<b>SPOOM</b>

OK thats the response i was looking for! When i made assumptions i started with 150cubic inches, not 122 cubes, so there was my first big mistake in my chain of math. if you re-calc using the math i just used, minus those cubes, you will find i was actually very very close to the numbers you just quoted me.

the whole reason for my post was not because i wanted to show how much power 4 cylinder could make, but to show how it can all be broken down into math based on simple cylinder pressure VS torque VS engine size.

Everything you said makes sense, except that part about 10PSI not being 10PSI depending on the turbo size. I was not aware that there were different kinds of 10PSI... only different efficiency points on a compressor map that would make a change in air tempeurature or accel factor of the air itself, but to my knowledge 10PSI was 10PSI so long as the temp was the same the motor would respond the same to the positive pressure. I have read parts of maximum boost, have it in my room, never finished it though.

 

[QUOTE]Originally posted by Kingtal0n

Quote:

Originally posted by rx7speed
<b> few problems with some of the things you said
first you said something about 420-440lbslbs/tq out of a v8 right
which by your own admission the pushrod v8's don't generally produce very good VE%
but yet you are giving the imported motor less VE% then a pushrod v8
</b> i used the V8@ 100% VE to keep numbers matching. comparing a 4cylinder @ 100+% under boost and a V8 at 75%VE isnt a very good way to compare numbers. by using 100%VE i can basically figure out how many "liters" the boost adds to the 4 cylinder motor... so when i subtract the VE from the 350 motor we can see just how much more power the 4 cylinder makes over 100%. also when did i say a 4 cylinder motor makes less VE? forget VE. in fact forget all the math. the question was never "is my math right" the question is am i even close? was i right baout the boost VS engine size VS horsepower? dont evade.<b>

also aren't most typical 350's more in the 300lb/ft range?
</b>
a stock 350 can make well over 300 Ft.Lbs, in fact that are almost all torque in stock trim. doesnt a stock TPI motor make like 340 ft.lbs? doesnt a stock pre-75 350 make almost 370 ft.Lbs of peak torque? <b>
second you talk about drivetrain loss
but with this are you taking into account the gearing as well?
ie
100lb/ft motor runs through a direct drive 4:1 axle
so it might dyno at maybe 90lbs/torque being the axle ratio is factored in to produce numbers showing drivetrain loss
when in all reality it might be making closer to 386lb/ft (400lbs/ft in an ideal world) because of that gearing
</b>
you cant factor in gearings because it plays no part in drivetrain loss whatsoever. frictional loss maybe, but thats only 1-2% anyways... and on top of that, extra gearing does not increase horsepower, and therefore does not increase torque. sure it may increase the speed the engine accelerates and give the motor more leverage (torque = force X length) on the ground, but it doesnt actually "add" torque, it just speeds up the rate at which the motor can make power. <b>

that's one thing about imports granted most the time they don't put out huge torque numbers on the motor itself
but most also use 4.1+ gearing which helps create torque at the wheels themself. that is partly why hp is a better factor in how fast a car would be. cause hp is a multiple of torque and higher rpms allow for more gear.
</b>
one again, gearing has no affect on horsepower at all. you increase the length which increases the "theoretical torque" but at the same time with a change in length you change the distance travelled, which means horsepower stays the same.
<b>

the motor is almost always producing MORE torque at the wheels then what a flywheel dyno would show
</b>
if that was the case then it would make more horsepower at the wheels also, which is NEVER the case. thats a really bass ackwards way of looking at it. <b>


also how do you have 10psi of boost with only a 10% VE? </b>

when did i say that? are you smoking stuff again?

well first thing I want to say

am I smoking my stuff again no
but my brain was messed up with no sleep
you know the really tired stuff where you fart and swear it didn't come out your butt but rather someplace else and have noclue where (true story)


but gearing does have an effect on torque as far as I know
now it doesn't add torque to the motor itself
but torque to the wheels does go up correct?
it's actuall force that is being applied to the tires is more then what the motor would produce
least from what I rememger in my physics class
that is the point I was trying to make with imports I think
even though there numbers at the motor might not be as high
but who knows my mind was half gone with sleep


and the 10%ve was supposed to be 90%ve at 10psi

but who knows
before I start talkingabout i will just shut up and go smoke a cig

 

First of all, I'd like to correct myself on the Neon engine. It's a 2.4, not a 2.0. I was tired and imagining that the new engine was a version of the old 2.0, which of course it's not.

The point that I was trying to make in a sleep-induced haze was that 10 psi is always 10 psi, but it's not always flowing the same amount of air. Example:

TD05-14B@15 psi = 405 cfm
TDO5-16G@15 psi = 505 cfm
TDO5-B16G@15psi = 550 cfm

As you can see, they are all compressing the air to 15 psi, but they are all flowing a different volume of air. As the volume of air increases, the potential for power also increases (assuming that you have enough fuel to match the air and the engine can withstand the additional pressure, of course.

Those turbos are all basically externally identical with the exception of the compressor size (they all share the same turbine). The 16Gs often come with a 7cm housing instead of a 6cm version, but you see the point I'm trying to make. Just looking at them installed in the car, you'd be hard-pressed to tell what you've got.

 

Rx7speed, gearing increases torque by trading off speed. Which means the actual horsepower stays the same. However, You can make up for a loss of engine torque with gearing if you have the rpm's to back them up.

It also means you can average the HP throughout the RPM range to compare 2 motors with different RPM ranges.

 

hehe
you saying the same thing I was saying


but I'm curious when all I keep talking about is how gearing will increase torque why everyone needs to remind me about hp?
not bringing that up as far as how it would increase hp


if anything the only real point I would bring hp into this is for which is better based on pure engine dyno
and I would say hp
hp is a better factor at going on how fast your car can go once you factor in gearing and everything else
two motors producing about the same torque but one has it moved higher up the rpm range uses some really high gears and now he is able to go faster
well ideal world situation maybe
but get the idea