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Help with setup of new engine - opinions wanted
Long post, sorry but had to get details in..
Alright, well I want to do an engine swap to my FD, something N/A. Ive been building boosted engines for the past couple years and just want to play with something different. Originally I wanted to build an N/A 20B for it, but I was unsure of the power output I could make with it, and didnt want to end up with something a stock or even lightly modded FD would hand its ass to. So I was fairly decided on an LS1 swap, but decided to get the rest of my car setup 1st, so thats what I did. Got the wheels, suspension, new bushings, rollbar, racing seats, etc all set up, engine was/is going to be the last step. I now see that GtoRx7 on this forum has done what I had wanted to do, with what I think are incredible results. He made close to 350RWHP on a mustang dyno with just a clean-up port (also ITB setup and S5 N/A rotors, check out his thread in the 20B forum), so now that has gotten me very excited about the 20B again ,being I think with some good aggressive porting I could come close to 400RWHP N/A on the 20B. I think torque was right around 200RWTQ. So now I have a dilemma, I cant decide if I want to go that route, or stick with the LS1 plan I was going with. I know the engines are completely different, and in the end its just all a personal preference, but i could really use some others opinions on each. With the LS1 head/cam package I was building, Id be looking at more power, about 450rwhp and 400RWTQ. Car will be mainly a weekend toy/show car, not really using it for any transportation purposes. Please dont start the rotary vs V-8 bashing BS in this post, thats been beaten to death. Both of these have their strong point, and Im just looking for some objective outside opinions. Thanks alot. |
From the showcar standpoint, I'd think a setup like gto's would definitely outshine the other choice you're looking at. I'm trying to remain unbiased, but I really think that 20B would kick ass out on the road course :)
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Umm..Just curious,why would you want an n/a FD?
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Originally Posted by Authentikdit
Umm..Just curious,why would you want an n/a FD?
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20B would be cool. I would rather you strap a turbo to it and run low boost, you could still run the piss out of it with little or no problems.
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You sound like you're thinking about some things that I've been thinking about at some time or another.
It sounds like the absolute power thing is less important to you than having an awesome car with an awesome engine. No mistake, either engine would be awesome, they are both great. I have to lean towards the N/A 20B though. While it's stupid to pick an engine or go to great lengths to build a car with a particular engine in it "because it's unique," the plus side is that there are lots of other great things about the N/A 20B. It's uniqueness is only a bonus. I cannot get over the sound, personally. The 20B is one of the best sounding engines ever, IMO. I don't quite remember if GtoRx7 lost weight overall or not after his setup was done, but remember that the non-turbo setup is cutting a lot of excess off the typical 20B swap. An LS1 would likely tip you a little heavier, but in it's defense, the handling isn't greatly (or probably even noticably) affected. There IS the potential, if you want to drop some major coin, to get the 20B even lighter with some aluminum side housings. That's what I'd like to see actually, a no-holds-barred all-out N/A 20B setup with all the trimmings and as light as possible. Maybe some day. Anyway, there's still room in that setup for more power. Remember that Gto had the semi-p ports cut, but not used. He also didn't do any lightening of the rotors or anything. I suppose you could try Renesis rotors, or have Racing Beat or someone else lighten up some S5 rotors for you, I think it'd be worth trying to see what kind of difference it makes. Speaking of the Renesis, if you look at Gto's dyno, it's got that ultra-flat torque curve that goes all the way to redline, resulting in that Renesis-like ladder of a power curve (except more of it, everywhere!). Personally, I LOVE that power curve because the car feels like it just keeps pulling all the way to redline. If you've ever driven an RX-8, you know what I'm talking about. So for me, that's another bonus. Plus, when it comes down to it, I've got a DSM with 350 whp that STILL weighs more than a stock FD (despite the fact that I've ripped a ton of stuff out of it) and it runs 11's and is faster than pretty much anything I ever run into. Even if you only hit 350whp, the reality is that it's still pretty damned fast. |
Nice post, you've outline alot of key points that I have been thinking about. The sound of a 3-rotor is amazing. And yes, a 350WHP FD should be able to trap close to 120MPH, which is no slouch. By no means a monster, but not slow. I also know that gtorx7s setup was not optimal when he hit 350HP, plus it was on a mustang dyno, which typically read lower than the more common dynojet numbers most people think in. Im definately leaning toward this way, but there is alot to be said about the LS1 potential also. The aftermarket for that is second to none.
Originally Posted by rarson
You sound like you're thinking about some things that I've been thinking about at some time or another.
It sounds like the absolute power thing is less important to you than having an awesome car with an awesome engine. No mistake, either engine would be awesome, they are both great. I have to lean towards the N/A 20B though. While it's stupid to pick an engine or go to great lengths to build a car with a particular engine in it "because it's unique," the plus side is that there are lots of other great things about the N/A 20B. It's uniqueness is only a bonus. I cannot get over the sound, personally. The 20B is one of the best sounding engines ever, IMO. I don't quite remember if GtoRx7 lost weight overall or not after his setup was done, but remember that the non-turbo setup is cutting a lot of excess off the typical 20B swap. An LS1 would likely tip you a little heavier, but in it's defense, the handling isn't greatly (or probably even noticably) affected. There IS the potential, if you want to drop some major coin, to get the 20B even lighter with some aluminum side housings. That's what I'd like to see actually, a no-holds-barred all-out N/A 20B setup with all the trimmings and as light as possible. Maybe some day. Anyway, there's still room in that setup for more power. Remember that Gto had the semi-p ports cut, but not used. He also didn't do any lightening of the rotors or anything. I suppose you could try Renesis rotors, or have Racing Beat or someone else lighten up some S5 rotors for you, I think it'd be worth trying to see what kind of difference it makes. Speaking of the Renesis, if you look at Gto's dyno, it's got that ultra-flat torque curve that goes all the way to redline, resulting in that Renesis-like ladder of a power curve (except more of it, everywhere!). Personally, I LOVE that power curve because the car feels like it just keeps pulling all the way to redline. If you've ever driven an RX-8, you know what I'm talking about. So for me, that's another bonus. Plus, when it comes down to it, I've got a DSM with 350 whp that STILL weighs more than a stock FD (despite the fact that I've ripped a ton of stuff out of it) and it runs 11's and is faster than pretty much anything I ever run into. Even if you only hit 350whp, the reality is that it's still pretty damned fast. |
I think the sound and the Renesis-like power curve really does it for me.
At the end of the day, I want a fast car. Sometimes it's nice to be able to run through a gear without hitting redline too quickly, you know? :) And it's also nice sometimes to not be dealing with dangerous amounts of power. The reality is that if you're building a car to be the fastest out there, you lose by default. There will ALWAYS be someone faster. So to me, if you really want a certain engine for the right reasons, it doesn't make sense to miss out on that just to gain a few bragging rights. On the plus side, it'd probably still be cheaper to rebuild the 20B, and it should be just as reliable as the LS1. |
Man, the 20B does sound amazing :git:
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Would you consider nitrous with the 20B? I made the same debate over in my head as well, but I would probably stick with going to the LS1. Wouldn't you be at about the same HP that GTO is a with his ITBs, etc. with a stock LS1 (Later model motors at least). And than at that point when you want to drop a little more coin, you would surpass it pretty easily. And as far as torque, is it even fair to compare the two? I have nothing against the rotary motor, I never had a problem with mine, but also want something different. I've always liked the muscle car sound, loved the body of cars imports put out and chose the RX7 for it's handling over other cars. For me it only made sense to mix the two.
I am doing the same thing you are with getting everything ready forst before I drop the motor, and even though I have a 2002 LS1 motor in my garage, I sometimes pek into the 20B section to see what's new. But I do agree with staying NA on the 20B. And 4even though I sound like I am flip flopping in sides, I am leaning more towards the LS1. Hey Rich, still going to come by and do a compression check for me? Luigi |
Torque @ 2750
This is from TQ
Originally Posted by gnx7
Dynoed today and made 431rwhp/380rwtq on 91 octane with zero knock. The car sounds good with dual 3" Magnaflow: muffs, Xpipe, and even hi flow cats in place!
Driveability is nice (1st gear bucks sometimes with too little throttle input when letting out the clutch) and I can shift into 5th going about 45mph then just putt along happily. A refresher on the combo: '99LS1/T56 Hinson: Kmember, torque arm, trans mount, alum driveshaft, tie rods AFR 205cc heads (66cc chambers) milled .024", MLS gaskets, flycut pistons Katech rod bolts, March pulley, Thunder Racing tensioner TSP 233/239 .603/.600" 112LSA cam (sounds healthy), 7.4" hardened pushrod LS6 intake, ported stock TB JTR 1 7/8" LT headers, radiator, stock FD fans, 3.5" cold air K&N 3.5" air filter (7" long cone shaped, pretty small, but no restriction!) Magnaflow: 3" cats, Xpipe, mufflers, tips March underdrive pulley, no a/c or p/s (feels great without p/s actually) RAM 910 clutch, alum flywheel, 3:90 gears, alum driveshaft, Turbo 2 LSD 18x10 Gram Light 57 pro rims/Mich Pilot Sport 275/35/18's (51lbs) non synthetic oils were used I don't have the graphs scanned but here are the corrected results on a DynoJet thru the cold air intake and K&N air filter in place on 91 octane tuned at Newtech Performance in Hayward by Nick: 295rwtq@2750rpm 310rwtq@3000rpm 340rwtq@3500rpm 365rwtq@4000rpm 370rwtq@4500rpm 375rwtq@5000rpm 380rwtq@5500rpm 365rwtq@6000rpm 350rwtq@6500rpm 175rwhp@3000rpm 235rwhp@3500rpm 275rwhp@4000rpm 320rwhp@4500rpm 360rwhp@5000rpm 395rwhp@5500rpm 420rwhp@6000rpm 431rwhp@6500rpm 431rwhp@6800rpm Happy with the results and only lost 1rwhp by running the K&N air filter! I gained 5rwhp by removing the screen in the MAF. I may switch to a smaller cam after I make some passes at the strip and hit it with a 100HP Nitrous Express wet shot. What I do like about the cam/setup is that I'm not really having bad traction issues in 2nd on the street tires listed above (rolling into it) but the torque down low is a little off where I want it to be on the graph at least. The car on the road does feel very strong and it thunders at WOT. From 4,500rpm to 6800rpm it pulls very very hard. BTW- I bounced off the rev limiter in 4th today so it certainly moves along and paints a smile on my face ear to ear. It's alive :jumping: ! Can't even compare it to the Buick GN setup I had in my FC. They are too different... but the LS1/T56 is certainly a lot more fun and controllable on street tires IMO. The Buick GN setup would certainly ET better with similar power levels. |
Im not debating at all that an LS1 will have more power potential N/A than a 20B N/A, and the torque will blow it away. But on the other hand, I think the 20B may be more fun, and in this case (may be a 1st for the rotary ;) ) maybe more reliable on a road race environment where you are keeping it at high RPM for an extended period of time. And yes, you are right that a bolt on LS1 probably puts down about what he did with his old N/A 20B setup, although you do have to admit that his 1st setup wasnt fully optimized and had capped off P-ports. Either way though, yes an LS1 has the potential to make more power. Still though, 400RWHP , even if it is only making 200rwtq still makes for a damn quick car, enough to have alot of fun in, plus the sound coming from the 20B is incredible ( opinion of course). Im still up in the air, which is why I asked this, but in the end if you are building a street car with no other purpose than to make as much HP as you can, you are always going to be disappointed, as there will always be something faster. You need to build what makes you happy.
Originally Posted by wptrx7
Would you consider nitrous with the 20B? I made the same debate over in my head as well, but I would probably stick with going to the LS1. Wouldn't you be at about the same HP that GTO is a with his ITBs, etc. with a stock LS1 (Later model motors at least). And than at that point when you want to drop a little more coin, you would surpass it pretty easily. And as far as torque, is it even fair to compare the two? I have nothing against the rotary motor, I never had a problem with mine, but also want something different. I've always liked the muscle car sound, loved the body of cars imports put out and chose the RX7 for it's handling over other cars. For me it only made sense to mix the two.
I am doing the same thing you are with getting everything ready forst before I drop the motor, and even though I have a 2002 LS1 motor in my garage, I sometimes pek into the 20B section to see what's new. But I do agree with staying NA on the 20B. And 4even though I sound like I am flip flopping in sides, I am leaning more towards the LS1. Hey Rich, still going to come by and do a compression check for me? Luigi |
Originally Posted by Rxmfn7
Im not debating at all that an LS1 will have more power potential N/A than a 20B N/A, and the torque will blow it away. But on the other hand, I think the 20B may be more fun, and in this case (may be a 1st for the rotary ;) ) maybe more reliable on a road race environment where you are keeping it at high RPM for an extended period of time. And yes, you are right that a bolt on LS1 probably puts down about what he did with his old N/A 20B setup, although you do have to admit that his 1st setup wasnt fully optimized and had capped off P-ports. Either way though, yes an LS1 has the potential to make more power. Still though, 400RWHP , even if it is only making 200rwtq still makes for a damn quick car, enough to have alot of fun in, plus the sound coming from the 20B is incredible ( opinion of course). Im still up in the air, which is why I asked this, but in the end if you are building a street car with no other purpose than to make as much HP as you can, you are always going to be disappointed, as there will always be something faster. You need to build what makes you happy.
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I'm really not a rotary guy per se, but I would be in agreeance that an N/A 20B, properly built and not leaned on too hard should be a very reliable motor. A mildly ported ~300 HP build should make for a reliable motor and a fun to drive car. I'm not as sold on the sound of the 20B, but it at least sounds better then a 13B. :)
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Yeah, I am not sold on the sound either. At times it is to much "BRAP BRAP BRAP" (I tried my best) for me.
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Nitrous is a good idea, too. I'd like to build an N/A 20B and throw a 50-shot or so on it. A little extra juice whenever you need it. :)
I'll probably get around to that as soon as the mortgage is paid off (read: sometime in the next 30 years). |
Are you trying to get some original ideas or are you looking for a rx7 forum vibe to direct your decision?
I just did the V8 conversion and ever time I fire it up I am blown away. Had a 435 rwhp single turbo rotary before and there is no comparison to the feeling of driving the LS1, it's 420 rwhp btw. I grew up lusting over an american V8 rumble but when the third gen came out I fell in love and had to have one. Now I have both and it is a blast to drive, cruise, look at, ... Sounds like you want a 3-rotor for the exhaust note, I'd suggest doing it one better and go for a NA 4-rotor, it's one of the most awesome sounding motors I've ever heard. |
Originally Posted by twokrx7
Sounds like you want a 3-rotor for the exhaust note, I'd suggest doing it one better and go for a NA 4-rotor, it's one of the most awesome sounding motors I've ever heard.
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I'm not looking for anyone to make my decision for me, I just wanted some opinions and thoughts that maybe I havent been over already. I've always liked rotaries, and just wanted to do something a bit different with my FD, but I still want a fast car. Im not going to let my preference for rotaries blind me to the fact than an LSx engine can pump out the power I want and more, but Ive just never really been a V8 guy. I dont care for the sound, and building them really doesnt do anything for me. Its hard to argue with the fact that a basic head/cam package can get me 450WHP or better though, but if I could doeven close with a N/A rotary I would rather go that route.
As for the 4-rotor, Ive actually looked into it, and just dont think I can/want to spend that much money on an engine.
Originally Posted by twokrx7
Are you trying to get some original ideas or are you looking for a rx7 forum vibe to direct your decision?
I just did the V8 conversion and ever time I fire it up I am blown away. Had a 435 rwhp single turbo rotary before and there is no comparison to the feeling of driving the LS1, it's 420 rwhp btw. I grew up lusting over an american V8 rumble but when the third gen came out I fell in love and had to have one. Now I have both and it is a blast to drive, cruise, look at, ... Sounds like you want a 3-rotor for the exhaust note, I'd suggest doing it one better and go for a NA 4-rotor, it's one of the most awesome sounding motors I've ever heard. |
You really ought to drive them. It will help steer you in the right direction. Post on the regional forum and see who is in your area.
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