 What makes our engines so underpowered?, Compaired to JDM's and other countries? |
 Apr 24, 2004 - 4:09 PM
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 Enthusiast  Joined Feb 8, '04 From KY Currently Offline Reputation: 0 (0%)  |
What is it that causes our engines to be so under powered? Is it the ECU's, or what?
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Apr 25, 2004 - 12:04 AM
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 Enthusiast Joined Dec 27, '03 From Nor Cal Currently Offline Reputation: 0 (0%) |
You know nothing... Auto 7gc GT-S are 17 second cars... which is about equal to an Auto GT. The auto tranny makes little to no use of the VVTLi. The reason the power peaks so high in the rpms... is because that's what it's designed to do. It's hard to build a high-powered 4 cylinder both small, and high-powered without that design. Valve timing and lift. That's the jist of it. That doesn't mean it's useless... or anything like that. It just makes the car slightly more difficult to drive because of the lack of low-end power. Full explaination on n/a 4 cylinders and how/why they make their power: If you want big low-end torque... look at the stroke. The stroke is what makes the big low torque numbers... but also, because of the stroke, the engine won't be able to revv effectively or reliably. Big torque 4 cylinders such as the 5SFE and Nissan's QR25 (2002+ Sentra SE-R V Spec) have large strokes. Both makes very large torque numbers in the low range (145 ft lbs and 175-180 ft lbs respectively)... but limited high-end HP. Although their HP numbers nearly equal their torque numbers... their hp per liter is no where near as good as high-revving high powered 4 bangers. The only reason the Nissan motor makes 175-180 hp is because of its size. You just can't have the most torque with the most HP all in the same n/a 4 banger. Now for the high-powered 4 cylinders... they revv to make their power. They have much smaller strokes (usually high-revving 4 cylinders have less than 87mm stroke) and they have much much higher compression (to make the most use of their high-end ability). That makes the engine put out a lot less low-end torque... so why do they make so much power? Valve timing and lift. Like pure racing motors, these engines have very agressive duration and lift cam lobes stock. In actuality, they can have anywhere from 2 different sets of cam lobes... to even 3 different sets per camshaft. Each lobe boasts a different duration and lift for its rpm range... so the big power maker, the most agressive lobes, are set for the highest range, when the engine is making the most induction. Basically, you can get as much as a 80 hp jump in some VTEC motors to toyota's 40-50 hp jump in the 2ZZGE. It's like nitrious! The it's done like that... so you can have a smog legal streetable cam profile in the lower rpms, while also having a racing inspired cam profile in the high-end. You can't have just the racing profile alone, because that will make for crappy emissions and extra crappy low-end. Now... both together... stroke and revvs. Honda has tried it... with the H22's... but that got too expensive really quick (H22 powered cars had a base price around 25k). They had to build the bottom end extra extra strong to balance out the poor rod ratio in the big stroke high revving H22s. That sucker had 195-225hp with a very very nice torque band around 150-160 ft lbs. Sounds good... so why'd they get rid of it? Expensive. I'm not even gonna mention Toyota's fabled BEAMS 3SGE... cause that's all it is. FABLED as with all of the 3SGE's. People have said that engine dynos anywhere from 150 whp to 160whp... which is far far less than where it's rated (rated at 197-200 bhp). That even includes the drivetrain losses... but also note: the 3SGE's were built as 'in between' as it got. 86mm bore, 86mm stroke. Perfect displacement and stroke for great low-end torque, and good enough rod-stroke ratio for stock revolutions above 8000 rpms (stock was a bit less)... Even still... that's old tech (90's tech). With today's technology... it all sums up to the Honda K20A. Perfect 'in-between' design (86m bore and stroke... 1998 cc displacement... EXACTLY the same as the 3SG's) with great low-end response and a LOT of high-end horsepower. They make anywhere from 160 hp 145 ftlbs of torque (K20A3) in the Civic SI... to as much as 220 hp and 150 ftlbs of torque in the K20A5 (Integra type R or RSX type R). There are VERY large differences also in these motors. K20A3's have iVTEC only on the intake side... while the K20A2 (RSX-S) and K20A5 (RSX-type R) have iVTEC on both intake and exhaust cams. These things are the sum of all above mentioned technology combined. My cousin has a Civic SI (heavily modded) and he revvs his to 8900 rpms daily without any troubles. His car can probably lay down a mid 14 second pass if not faster... we don't know yet... but he has beaten an H22 swapped 2 door accord that ran a 15 FLAT by about 4 car lengths... so that's my guesstimate. Anyways... know the technology behind each motor... before you can really say what's better than what. You want torque or power?... that's the question. This post has been edited by Kwanza26: Apr 25, 2004 - 12:06 AM -------------------- "It's ok to be naked girl... I'm an artist!"
1995 AT200 Celica ST: stocked out daily driver... 1984 AE86 Corolla GT-SR5: silvertop 20V 4AGE project car jacked up with goodies... 1991 SW2x MR2 n/a: bare bones hardtop model soon to be... |
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Posts in this topic
Rjb23 What makes our engines so underpowered? Apr 24, 2004 - 4:09 PM
orvillescelica Keep in mind that the 5sfe and the 7afe are old en... Apr 24, 2004 - 4:42 PM sinner96ST QUOTE (Rjb23 @ Apr 24, 2004 - 2:09 PM) What i... Apr 24, 2004 - 4:53 PM Supersprynt Its not because theres no demand, theres always be... Apr 24, 2004 - 5:05 PM sinner96ST QUOTE (Supersprynt @ Apr 24, 2004 - 3:05 PM) ... Apr 24, 2004 - 5:12 PM Jabberwock I think you are wrong sinner96ST...I agree with Su... Apr 24, 2004 - 5:42 PM sinner96ST QUOTE (Jabberwock @ Apr 24, 2004 - 3:42 PM) I... Apr 24, 2004 - 6:02 PM toyotaspeed_90 QUOTE (orvillescelica @ Apr 24, 2004 - 9:42 PM) Ke... Apr 24, 2004 - 8:37 PM Jabberwock Well the matrix is pretty good for toyota...hehe m... Apr 24, 2004 - 8:39 PM TRDCelicaST A Hyundai Elantra!? Oh god, that might be wor... Apr 24, 2004 - 8:39 PM Mousetrashdiver The only advantage i see the newer ones having is ... Apr 24, 2004 - 9:42 PM Jabberwock hehe yeah elantras are pretty bad but thats what h... Apr 24, 2004 - 9:43 PM sinner96ST I love the look of my car, but honestly, i'm p... Apr 24, 2004 - 9:48 PM Pali_playa QUOTE (sinner96ST @ Apr 24, 2004 - 10:48 PM) I lov... Apr 24, 2004 - 10:03 PM sinner96ST yeah.. the engines are meant to last forever, but ... Apr 24, 2004 - 10:07 PM toyotaspeed_90 toyota put lower motors in the celica at that time... Apr 24, 2004 - 10:17 PM brianforster i dont see the big hype about the celica gts, its ... Apr 24, 2004 - 11:01 PM Uppitycracker Im sick of hearing a bunch of kids bitch about car... Apr 25, 2004 - 12:37 AM uzthedentist i assume its due to fuel, the 100ron rating of jap... Apr 25, 2004 - 8:22 AM Junior To answer the original question, toyota cars with ... Apr 25, 2004 - 11:41 AM playr158 QUOTE (TRDCelicaST @ Apr 24, 2004 - 8:39 PM) A Hyu... Apr 29, 2004 - 11:10 AM playr158 hey guys, i must apologize for the hyundia owner... Apr 29, 2004 - 11:55 AM KAMiX QUOTE Im sick of hearing a bunch of kids bitch abo... May 2, 2004 - 7:45 PM
saleeka First things First- AMEN KWANZA... Nice to see peo... May 2, 2004 - 9:00 PM |
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