Single turbo vs V8 need help
06-21-14, 12:21 AM
#51
I always find it interesting that people complain about a high rpm car being strung out or no tq down lot, etc. Granted, it'll be a little bit more difficult to do a rolling burn out at 2000rpm but you're also not limited to ~6500rpm. You're also driving a motor where, if kept in the lower rpm range, will have extremely mild manners.
Regardless, as is known by any one who isn't delusional, you need quality parts and maintenance to keep an engine running, rotary or otherwise. Every one knows about pre-mix, but it seems everyone over looks water and/or meth injection. Both seem to make the rotary virtually indestructible. Below is a link to a fellow making a lit under 600rwhp on a dual rotor. Reliably. On pump gas. Not e85.
Water Injection
Regardless, as is known by any one who isn't delusional, you need quality parts and maintenance to keep an engine running, rotary or otherwise. Every one knows about pre-mix, but it seems everyone over looks water and/or meth injection. Both seem to make the rotary virtually indestructible. Below is a link to a fellow making a lit under 600rwhp on a dual rotor. Reliably. On pump gas. Not e85.
Water Injection
06-21-14, 12:46 AM
#52
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I never said anything about WHICH is lighter/heavier... please re-read.
As far as all else being equal, provide some facts before you make any claims.
A strung out rotary comes with a great many failure critical systems despite having few moving parts. Any problems with cooling (water pump, radiator, hoses etc), fuel (pump, filter, injectors, even just a bad tank of gas), air management (blowoff/wastegate, vacuum leaks), and the engine might be done. Rotaries can be awesome, but damn they are unforgiving. I personally found the rotary less fun to drive since I found never trusted it. We all understand that detonation will spit out apex seals, but I've never seen a good explanation for why coolant seals let go.
Then there's what you can "upgrade" to. IMHO, a single turbo rotary making good power (lets say 450+ rwhp) typically has a terrible torque curve which is pretty non-existent below 3500 rpm. The big single often leaves you driving on e85 or race fuel which is a PITA for many reasons. There's little to no margin in the tune if you want to make power, certainly no enough to tolerance any given component issues as mentioned above. Then, when the power comes in, it hits hard in a big rush, so feathering throttle is challenging. They're simply harder to drive fast. Can you? Absolutely yes. Is it easy? No.
A v8 on the other hand is all about instant gratification. The power is always there. It'll make more torque by 2500 rpm than most rotaries do at redline. Any heads cam setup winds out nicely. Literally my favorite comment from a rotary buddy after I took him for a ride was simply "you've ruined me". All the preconceived notions just fall away after you get a ride in one. It doesn't happen for everyone, some folks just like what they like, but if you're looking to make an objective evaluation of things you should find someone local and get a ride.
The simple fact is that when I did the swap, I quadrupled the displacement, I tripled my horsepower, and my gas mileage went up. I don't know how that doesn't defy physics but there it is.
My advice is that if you have a good running car, NOW is the best time to swap it, when all the goods you're about to take out are still worth top dollar to the purist who just blew up his stuff. Financially speaking and in terms of time committed to the build, the worst scenario you can have happen is that you do go single, then you blow it up, then sell your setup for pennies, and you THEN finally swap it.
If they made a corvette in 9/10ths scale I might be driving one. Until that happens a v8 rx7 is the next best thing.
Good luck!
Then there's what you can "upgrade" to. IMHO, a single turbo rotary making good power (lets say 450+ rwhp) typically has a terrible torque curve which is pretty non-existent below 3500 rpm. The big single often leaves you driving on e85 or race fuel which is a PITA for many reasons. There's little to no margin in the tune if you want to make power, certainly no enough to tolerance any given component issues as mentioned above. Then, when the power comes in, it hits hard in a big rush, so feathering throttle is challenging. They're simply harder to drive fast. Can you? Absolutely yes. Is it easy? No.
A v8 on the other hand is all about instant gratification. The power is always there. It'll make more torque by 2500 rpm than most rotaries do at redline. Any heads cam setup winds out nicely. Literally my favorite comment from a rotary buddy after I took him for a ride was simply "you've ruined me". All the preconceived notions just fall away after you get a ride in one. It doesn't happen for everyone, some folks just like what they like, but if you're looking to make an objective evaluation of things you should find someone local and get a ride.
The simple fact is that when I did the swap, I quadrupled the displacement, I tripled my horsepower, and my gas mileage went up. I don't know how that doesn't defy physics but there it is.
My advice is that if you have a good running car, NOW is the best time to swap it, when all the goods you're about to take out are still worth top dollar to the purist who just blew up his stuff. Financially speaking and in terms of time committed to the build, the worst scenario you can have happen is that you do go single, then you blow it up, then sell your setup for pennies, and you THEN finally swap it.
If they made a corvette in 9/10ths scale I might be driving one. Until that happens a v8 rx7 is the next best thing.
Good luck!
I always find it interesting that people complain about a high rpm car being strung out or no tq down lot, etc. Granted, it'll be a little bit more difficult to do a rolling burn out at 2000rpm but you're also not limited to ~6500rpm. You're also driving a motor where, if kept in the lower rpm range, will have extremely mild manners.
Regardless, as is known by any one who isn't delusional, you need quality parts and maintenance to keep an engine running, rotary or otherwise. Every one knows about pre-mix, but it seems everyone over looks water and/or meth injection. Both seem to make the rotary virtually indestructible. Below is a link to a fellow making a lit under 600rwhp on a dual rotor. Reliably. On pump gas. Not e85.
Water Injection
Regardless, as is known by any one who isn't delusional, you need quality parts and maintenance to keep an engine running, rotary or otherwise. Every one knows about pre-mix, but it seems everyone over looks water and/or meth injection. Both seem to make the rotary virtually indestructible. Below is a link to a fellow making a lit under 600rwhp on a dual rotor. Reliably. On pump gas. Not e85.
Water Injection
I know some people are arguing for the v8 from a financial standpoint... there might be more upfront costs but back it's much more forgiving on the back-end.
06-21-14, 01:37 AM
#53
Performance, you made a post that attempted to brush off a 100lb difference. I pointed out that a 100lb difference is easy to feel. Please reread. I used fuel as that is relateable. My point remains; even if we're talking about ballast added in an ideal spot. And that's the engine weight alone, again, "everything else being equal", as in, fully dressed. I recall finding full dressed weights for various 13b's on the club. ls1 weight was the published manual weight from chevy when they sold ls1 crate motors. Find them yourself.
To make an LS1 reliable means changing out rod bolts at the least. When being driven hard there is also excessive blow-by that needs to be addressed as well as potential issues with the steam vents. When buying a used engine it is not uncommon to simply start changing seals, gaskets, etc. such that it will be one less thing to do later. I know people that feel anything short of a full tear down with a swap motor is too risky.
Adding a relatively simply system as a means to block the usual rotary catastrophic failure vector (heat/knock) AND allow much higher power potential vs. selected modification/added parts/altered systems for reliability... Both of which are upfront costs to reduce back end costs. I'm unsure of why you would discount adding a system that does this while trying to justify the base cost of a swap (one giant "added system") alone as a front end cost that will some how reduce back end costs when this can be done by adding a system and keeping up with maintenance?
To make an LS1 reliable means changing out rod bolts at the least. When being driven hard there is also excessive blow-by that needs to be addressed as well as potential issues with the steam vents. When buying a used engine it is not uncommon to simply start changing seals, gaskets, etc. such that it will be one less thing to do later. I know people that feel anything short of a full tear down with a swap motor is too risky.
Adding a relatively simply system as a means to block the usual rotary catastrophic failure vector (heat/knock) AND allow much higher power potential vs. selected modification/added parts/altered systems for reliability... Both of which are upfront costs to reduce back end costs. I'm unsure of why you would discount adding a system that does this while trying to justify the base cost of a swap (one giant "added system") alone as a front end cost that will some how reduce back end costs when this can be done by adding a system and keeping up with maintenance?
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