Pennock's Fiero Forum Technical Discussion & Questions - Archive
Why does American engines produce less HP relative to size/liter than foreign makers (Page 2)
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Why does American engines produce less HP relative to size/liter than foreign makers
Originally posted by I'm Back: Oh, so head design must accompany larger displacement for the larger displacement to be afctor? So there is a replacement for displacement you’re saying. How about the better heads on a 350? Perform better than a 350 with stock heads? Yep. So you’re saying that an engine, not necessarily 350 to 383, but a small block compared to a big block will have the same rpm potential? Gonna turn a 454 to 9,000 rpm easily?
What I meant was that if the ports are saturated, then a 383 won't really make ANY more power than a 350, it'll just shift the powerband to a lower RPM. If there's "room" in the ports for increased airflow, then a 383 with the same cam as a 350 will make 10% more power, because of the displacement. The other effects, like average piston speed, rod ratio, etc. don't add up to the difference the displacement makes. Yes, you could rev the 350 higher, but then it becomes less streetable and harder to drive. Just like the Vortec 7400 big block Vette, the larger engine is more streetable. No I'm not advocating tossing an iron big block in place of an aluminum small block, as I'm too weight conscious for that. Weight apparently wasn't an issue for the guy who did that swap.
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Because I write TOHC instead of DOHC and you don’t like it? I think I have read TOHC on a Jap 4 banger. You know I’m not from Europe. Splitting hairs about the terminology of TOHC vs DOHC is like correcting errors of syntax in a post. You’re a smart guy, you knew what I meant, just didn’t like the way I wrote it.
I wrote that I thought about that after I posted, and that I just wasn't used to seeing it that way. Was I unclear when I wrote that? Don't blow a gasket.
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Who in the hell is advocating putting a 4 banger in a Vette? Who was talking gas mileage? You’re intentionally taking my points out of context to attempt to persuade some that displacement is king. I’m talking a steel 350 from 1978 versus an LT-1 from 1995 versus an LS-1 from 2000. Same displacement, way different performance based upon technology that REPLACES the need for increases in displacement.
The natural extension of your argument is that by increasing technology further, a reduction of displacement will achieve the same performance. That's what I was pointing to with my SR20 Vette example. Higher VE, higher RPM and loads of boost can yield the same acceleration performance, but daily driveability suffers with the smaller engine.
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Hate to burst yours, but they made Caprices before the introduction of the LT-1. The example I was referring to was that an old, nasty steel block/head 350 is pathetic compared to an LT-1, which has essentially the same lower end. I know the LT-1 has reverse flow cooling, I’m not sure about the LS-1. Of course I realize there is technology in the LS-1, there is also a lot of head technology in the LT-1. The presence of pushrods merely means it’s more difficult to get high rpm’s from the motor.
Again, chill out. I was just havin' fun with the Caprice thing. I know they've made Caprices since before forever and they used to put TBI boat anchors in them.
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OK, and weight wasn’t an issue apparently. I’m not knocking the big block Vortec in any way, what a sweet motor, but there are other ways to get hp than with increased displacement. For a guy that went N* to be advocating large displacement, heavy motors, I have questions. Not only that, but you went 5-speed at least in part to keep weight down, so you know weight is a huge issue.
Weight's an issue for me. It apparently wasn't for the guy who did that swap. The result was the same power and ultimate performance, but an increase in the "easy to drive quotient".
[quote]Ok, talk GM into it. As for driveline issues, the article is hearsay and the swap is new so we’ll see what happens to it, or rather we won’t.[/quote
Torque is torque, and people are getting 450+ rwhp & 400+ rwtq out of LS1's without breaking T56's. These engines however are pretty strung out and less pleasant to drive than stockers.
The Northstar makes a fun to drive Fiero. However, the LS1 has the same TQ/RPM characteristics as the Northstar, but has more torque at all RPM points because of its larger displacement. The Northstar's potential for N/A HP is at least as great as the LS1's, but at the same power level, the Northstar will ALWAYS be harder to drive than the LS1 because it will ALWAYS be more cammed up and more strung out. I sure wouldn't mind an extra 1.1 litres in my N*.
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05:27 PM
SplineZ Member
Posts: 952 From: Edmonton, Alberta, Canada Registered: Nov 2002
I dont think we are behind the times at all. The majority of consumers out there are still wanting the big torque cars with lots of luxury. GM has always went for the classic example of majority. Thus, they will be offering these "couches on wheels" as long as there is a demand. See how they came out with the Ecotec on time. Only the compacts have the motor for now due to the recent boom in younger auto-buyers.
GM has always had a history of following popular demand. Right now, popular demand is bigger cars, bigger motors and sporty, but economical. Thus we have the Buick Century, Pontiac Bonneville, Grand Prix for all the couch potatoes out there. The Grand-Am is their sporty, but economical model.
With the new generation speaking up, you can expect to see more of the ecotec and compacts making their way into the domestic market.
Another point to follow, is that we have not had a need for high-revving motors and DOHC technology. As was mentioned before, taxes exist for the people with the bigger engine. In Japan, for example, they are taxed on how many litres a motor is. This is why you have a 1.6L DOHC with 100hp per litre. They want the power, without the extra taxes.
I'd hate to be the guy with an LT1 over there...
Great discussion!! Keep it going!!
------------------ #7277 of 46581 built in 1987. My thoughts are on you Sean and Chris! Come back safe!
We like quiet engines so we can blather with Maggie and Harry about the last canasta game. We are not comfortable if we feel the road. The interior is climate controlled and the vehicles that sell the most are the ones that have seats like our sofa at home. We travel 20-50 miles and feel like we've gone a long way. To actually HEAR the engine? Oh NO! Our Automobile is more of an extention of our living room than it is a "motor vehicle". And most of us do not feel comfortable in anything less than 200 inches long and under 3000 lbs.
Who in the hell is advocating putting a 4 banger in a Vette? Who was talking gas mileage? You’re intentionally taking my points out of context to attempt to persuade some that displacement is king. I’m talking a steel 350 from 1978 versus an LT-1 from 1995 versus an LS-1 from 2000. Same displacement, way different performance based upon technology that REPLACES the need for increases in displacement.
[rant] Actually the LT-1 is not from the 90s. The LT1 is. The LT-1 is from the 70s IIRC.
Sorry, I'm anal. LT1 and LT-1 are two different engines. [/rant]
I believe you have to consider torque as mentioned numberous times and also consider where you are driving. I have a 3800 SC and drive on hills (Pittsburgh) in lots of traffic. It's a great car for that. I've driven those little high reving foreign cars and they are hell, not bad on a highway, but just hell on hills and trying to get around town. I seldom ever go over 3000 RPMs with plenty of power to get around.
Because some of us don't like rebuilding boosted engines every 25K miles.
How about every 1/4 mile? Even though those Nitro Hemis are strictly a race motor, its still phoneminal how much HP they can generate, they said there close to 5000 HP now! To put that in perspective thats 600HP PER cylinder. Thats like having 2 300 HP LT1's per cylinder I heard a driver once comment that loosing a cylinder on one side will cause the car to pull to that side due to the lack of exhaust thrust on that particular header.. thats nuts!
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12:00 AM
Leper No longer registered
Report this Post08-08-2003 12:22 AM
Leper
posts Member since
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Originally posted by SplineZ: Not the same engine... James Z
Oops
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12:22 AM
88Fiero2M4 Member
Posts: 349 From: Stratton Colorado United States Registered: Jul 2003
on that note my out dated Pushrod 5.7L V8 in my Chevy Pickup makes about 210 HP stock. However I would still put it up against any Toyota Pickup in a pulling contest and would out pull it by far. Not to mention that all I need is a differant Cam and I can pull over 450 Hp out of it, infact with around 5K I could have an engine that would produce over 1000 HP and you cant do that with those smaller engines. As a friend says There is no replacement for Displacement. My cousin worked for a Preformance Mechinic shop in Ft Collins near the airport. They took a 350 and tuned it to 1200 HP and stuck it in a White Chevy Chevelle. Now that car could really move.
------------------ Don Pottorff Red 88 Fiero 2M4 Silver 86 Fiero 2M4
[This message has been edited by 88Fiero2M4 (edited 08-08-2003).]
I am not getting into any arguments here, if I had my way I'd have an S2000 and a Vette, just depends on the mood you're in. I didn't get to read all of this thread yet so forgive me if this was already mentioned, the LS1 is an extremely compact engine for its displacement. Pushrod engines have much smaller cylinder heads which make packaging them into the car much easier. Going back to one of the first posts comparing the 3800 to a Nissan 3.5, go look over those engines, the Nissan looks huge because of the heads. I am not talking about weight but size. Look at the DOHC 4.6 Ford used in some Mustangs, it dwarfs the LS1. I realize that this is not the reason American car companies stick with these engines but it is one more factor.
Because some of us don't like rebuilding boosted engines every 25K miles.
I seriously doubt you'd have to. Rotary engines aren't as unreliable as you'd think. They are as unrealiable as any engine that isn't properly cared for. There's lots of different things you have to do to take care of a rotary engine as opposed to a piston engine. This is exacerbated by the boost. You won't have to rebuild that often, but you will have to watch the engine fairly closely.
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03:27 PM
GTFiero1 Member
Posts: 6508 From: Camden County NJ Registered: Sep 2001
I heard a driver once comment that loosing a cylinder on one side will cause the car to pull to that side due to the lack of exhaust thrust on that particular header.. thats nuts!
i believe that. I was stadning right behind the left exhaust header in the rear on a Nitro dragster during a test starting at the matco nationals in english town. They started it and instantly exhaust fumes were in my face, so i squated down a bit even though it didnt help much. It was idling for a while and keep note i didnt have my hand on the ground or anything because i was covering my ears since it was extreamly loud. Then on of the guys reached up and tapped the throttle and WAM the exhaust just hit me and damn near nocked me over, i caught myself just in time, and it sounded like he didnt even hit it enough to go over even 3 grand so it was not at full power
Even though those Nitro Hemis are strictly a race motor, its still phoneminal how much HP they can generate, they said there close to 5000 HP now! To put that in perspective thats 600HP PER cylinder. Thats like having 2 300 HP LT1's per cylinder 
I heard a driver once comment that loosing a cylinder on one side will cause the car to pull to that side due to the lack of exhaust thrust on that particular header.. thats nuts!
