jimlab

Yeah... itty bitty cylinders.

While what you said is true for the most part, 4 valves per cylinder presents a packaging problem. If you've got a small 4-cylinder engine, running single or dual overhead cams isn't that much of a problem. You can just lay the engine over at an angle. If you're talking about a V8, overhead cams makes the engine significantly taller and wider, as well as adding to the complexity, cost, and weight.

The Z06 Corvette's LS6 may not be as complex (technologically advanced to some people) as the ZR1 Corvette's 32-valve DOHC LT5, but it's far cheaper, far lighter, far smaller, and actually has more power potential overall.

Bottom line, 4 or more valves are not necessarily better than 2 when package size, cost, or weight are an issue, or when adequate airflow can be achieved with only 2 valves. The engines in the NHRA pro classes are proof that a 2-valve pushrod configuration can make more than enough power and turn more than enough rpm to suit anyone's needs.

Black91n/a

You do have some valid points, but there are many dohc, 4 valve V-8's out there, like in the Mustang SVT Cobra, Toyota (and Lexus) have at least one, Nissan (and Infinity) have at least one, and there are several European ones (BMW, Merceded-Benz, Jaguar, etc). It's not that big a deal to do obviously because it's been done many times. BTW I never said 2 valves can't make power, it's just not the optimum configuration.

jimlab

While I won't argue that you can get more valve area with 4 or 5 smaller valves than 2 larger ones, when bore size reaches a certain point, you can easily get all the air flow you need from 2 valves and dispense with the extra complexity, cost, size, and weight of a multi-valve configuration. Case in point...



BTW, you do realize that overhead cams and multiple valve configurations aren't a recent technology, right?

turbojeff

iTrader: (30)

So many points I want to make here...

The thing that sucks about mustangs and camaro isn't the motor, it is the chassis and suspension. They are generally old designs that were optimized for cost rather than handling performance.

A lightweight 350 (Al heads and intake) is sorta heavy but puts out huge power.

A lightweight 302 (AL head and intake) isn't too heavy but doesn't put out as much power. 351's windsors put out more power but from my limited knowledge aren't really a strong platform to build from.

LS1/LS2 are relatively light and put out a lot of hp for the weight.

Indy cars have V8s, Ferrari, Lotus, BMW, Mercedes and Porsche make/install V8s in cars that handle quite well. I'm not a huge racing fan but V8/10/12s are pretty popular, traction control works pretty well and allows a 1200-1500lb car to handle 700-1000 hp pretty well.

The V8 is a balanced in the 1st and 2nd order IIRC. The inline 6 is balanced also but is harder to package for similar displacement.

If Mazda made/sold a decent V8 you'd probably see Miatas and FDs OWNING SM2 in auto-x. Great chassis and suspension only needing a large displacement motor.

owen is fat

lol, I'm sure a lot of guys think these are super-recent technologies...

gnx7

iTrader: (10)

The thing that sucks about mustangs and camaro isn't the motor, it is the chassis and suspension. They are generally old designs that were optimized for cost rather than handling performance........

Jeff- you hit the nail on the head.

I love RX-7's.... I've owned 5 of them... not as many you!!!

I just want to go fast reliably and for as little $$$ as possible. 28mpg on the highway isn't a bad tradeoff either.... plus running 10's n/a is my goal with road race suspension and drag radials on the car (for the strip only).

-GNX7

RETed

I guess you missed the part about AWD...
If you don't have direct experience with high horsepower AWD experiences, please don't reply.


-Ted

fc3s-gxl

FORGIVE ME WISE ONE FOR MY IGNORANCE LOL GIVE ME A BREAK U GUYS NEED TO CHILL SEEMS LIKE NO ONE GETS LAID IN THIS FORUM LOL

Jims5543

iTrader: (2)

1993 13B-REW Pettit Street Port - HKS T-04E - Motec M-4 - Full suspension Mods - 3" Exhaust - Full interior including stero & Bazooka tube - No A/c or P/S - Its a total street legal car that I race AX with. 400 RWHP @ 15 PSI.

I run it on Hoosier Slicks 10" with Circle 16x9.5 Rims.

I cosistently set FTD's soundly beating AP Cobras both on tight courses and fast ones. I came in Second overall at the RR by default - hit a cone after the finish hydroplaning in the rain. Otherwise I would have had the FTD by over a second.

Why the 13B-REW? Because it fell in my lap and I needed an engine. 13B-RE would be the way to go otherwise.

Good luck on youre ultimate FC - I love mine and wouldn't change a thing.

owen is fat

/\/\/\ sick.
nice looking setup, good to hear you can really do well on 10" Hoosiers with that kind of power as I'm trying to see what will work for me in autox this upcoming year, being so new to FC's and the LS1FC setup Ive got.

any mods to fit the 10" Hoosiers out back or is it just "tight" ?

run_rabbit_run

It's a matter of choice, priorities and passion guys.

Not every one wants a V8...

run_rabbit_run

I certainly don't...want to hook me up?

speedx7

LS1=PX7
20b=RX7

Simple

RX-Ben

I suppose...but I'm assuming everyone here wants to go fast, reliably, without breaking the bank or ruining the handling of the car. The cheapest, most reliable way to reach this end is with an all aluminum V8.

owen is fat

well thats where youre wrong, some guys here are not too concerned about reliability. I think they have become accustomed to rebuilds and such over time by immersing themselves into the rotary world. its very easy to lose sight of the real world concept of reliability. they are bent on running a rotary into a destructive path in order to get huge power out of it...

plus most of them have no true understanding of how small and short the LS1 actually is... and how modern it is... and how reliable it is... and how simply it drops into an FC... and how you can fire it right up in the FC after hooking up 10 wires.

RETed

Total bullshit.
Have you done that "small and short" LS1 swap?
What was your budget?

Sure, I'm not going to fight the fact that the rotary engine is more delicate, but reliability is more a factor of maintenance and keeping detonation out of the picture.
You sure destroy a piston engine from detonation almost as easy as a rotary engine.

A 400hp 13B is a set formula by now.
Big turbo
Big FMIC
Big fuel
Stand-alone EMS
Rebuild
Porting
This easily slips under $10,000.

I haven't seen an LS1 that came 500bhp stock?
Apologies in advance if this is a myth.
So on top of the LS1, we're talking typical piston engine upgrades like cams, headwork(?), intake, ECU modification (or are we talking carbs here?), etc...
Then, you need to factor in the cost of the swap into the RX-7.
The swap / adapters / engine mounts are at least a grand, right?

I think at this level, the LS1 edges out the 13B by a significant amount - at least a grand?
But, the LS1 does have an edge on reliability due to the fact it's still NA.

So lets start to bump the power level up to the 600hp to 700hp range...
Can the LS1 do this in NA form?
I highly doubt it short of some very expensive parts and engine work.
This necessitates forced induction, which means several thousand dollars more work.
I can do a 20B swap at around the $15,000 mark.
This makes the budgets somewhat similar at this point...
I still don't see the "small and short" here.
At 600hp - 700hp level for a 20B, this isn't "huge power".
I call 800hp - 900hp "huge power" for a 20B...



-Ted

jimlab

True, but a piston engine will usually shrug off light detonation that would leave a rotary in need of a rebuild.

I haven't seen any rotary engines that came with 500bhp stock either. What's your point?

Cam, head porting, possibly an intake, but LS1 Edit and a lap top is all you need to reprogram the stock engine management system for mods...

Maybe for an FD. $360 from Hinson for an FC. The rest is him trying to pimp cooling system and fuel system upgrades. You'll have to have your driveshaft modified, but any qualified shop can do that for $100 or so.

Have you priced single turbo kits and aftermarket engine management for rotary cars lately?

It would have an edge in reliability even with forced induction. It has more displacement. It doesn't have to work nearly as hard to make as much or more horsepower.

A big solid roller cam, a set of AFR heads, and a stroked bottom end would make 600+ horsepower pretty easily for about $10-15k. On pump gas. In fact, LG Motorsports just trapped 140 mph with a stock displacement naturally aspirated LS1.

http://www.lgmotorsports.com/images/media/lg140.wmv

A supercharger for an LS1 is less than most single turbo kits for rotary engines and doesn't require the additional cost of a massive intercooler.

I've yet to see these 900-1,000 horsepower 20Bs that people seem to think damn near fall out of trees and into their cars. If it were really that cheap and easy, you'd see a lot more 20B cars, and if they were so reliable, no one would be converting to V8s.

RX-Ben

Don't mention carbs! This is the 21st century!

A head and cam swap can be done on an LS1 to yield 450+ RWHP on pump gas ALL DAY EVERY DAY. 350 lb/ft tq from 3500 on up. The only wear item in this setup are the valve springs ($150) which may need replacing every 20K or so miles. I just picked up a head/cam swap for $1500. Owen has posted his complete swap cost list INCLUDING wheels/tires...absolutely everything. He did his swap quickly, with basic tools, in a driveway. His major hurdle was remembering to hook up the starter wire and bleeding the clutch master cylinder. Honest. No BS. My garage is down the street from where he lives and I built his exhaust.

You can get around 650+hp with a bit of engine work on the LS1 , but the cheapest route to huge numbers would be turbocharging. The LS1, with a forged rod/piston setup, loves boost. Most people don't do this since it really isn't needed. But anything up to 1200+hp setups are easily possible, just pick the size of the turbo. This would add about $6000 (though could probably be done in a pinch about $4500) to the cost of the swap, complete and ready to roll.

The beauty of the LS1 swap is that parts are available widely and cheaply. You can go anywhere to get your car worked on if you are say...on a cross country race and something goes wrong. Who is going to have critical parts for the 20B?

What in the world are you going to do with such massive power? Plan on breaking 250 mph? The acceleration figures of an LS1 FC are limited by traction as it is. Imagine the mayhem that results with a head/cam upgrade which will raise rwhp by 50%. Take a ride in a stock LS1FC before anyone decides they need insane power levels. Fat torque numbers will seriously change your outlook on life.

Ben

RETed

I guess I've been extremely lucky.
Severe pings (*tink* hammer on a metal pipe) on two separate occasions on a "fresh" rebuild did not hurt anything.
EGT spiked to 900C; normal heavy load EGT is 760C max.
Stock 3-piece, 2mm Mazda OEM apex seal cut down to 79.90mm.
I dunno why this hasn't let go...
Although it's on a low power set-up (250hp at the wheels) on a 13BT, this is probably one of the main reason why it's still together.
The new 2-piece, 2mm Mazda OEM apex seals should give a little better detonation resistance also.


Wrong choice of words...should be "crate motor"...?


Approximate cost?
$1,000?


[QUOTE}Maybe for an FD. $360 from Hinson for an FC. The rest is him trying to pimp cooling system and fuel system upgrades. You'll have to have your driveshaft modified, but any qualified shop can do that for $100 or so.[/QUOTE]
Does the GM trans just drop in?
Clear the firewall?
Shift lever installs in the stock Mazda position?
So what does GM trans typically costs?


HKS cast manifold
TS04 runs under $1,000 from cheapturbo.com


Sure, I agree.

Prices???

Last time I checked, a Paxton / Novi set-up is like $3,000+.


Oh, I agree.
I have no reason to build something that extreme.
I don't have a custom who wants to get that crazy.
Triple GT2835's should do the trick at around 20psi or so...
But we're talking over $4,000+ in bare turbos!

Side note, you old 20B motor put down 232 with no forced induction.
We're hoping to get 600 at the wheels sometime in '05!


-Ted

RETed

Oh, I agree.
Anything over 400hp scares me!
5xxhp 20B has been done.
I guess "600" is just a nice round number that hasn't been done on a street vehicle.
If the owner could afford some expensive GT-series turbos, I would shoot for 900.


-Ted

jimlab

For porting, cam, LS1 Edit, and odds and ends? About $2,000-2,500 if you do the R&R yourself.

You can buy a brand new T56 for $1,700 from GM, but most people are getting their LS1/T56 combinations for $3,000-3,500 from ebay and other sources. Some include the ECU and harness, others don't. I can only speak for the FD as far as fit.

With a turbo and a manifold. How about piping? Plumbing? Clamps? Hoses? Intercooler? Injectors? Computer upgrades? If going to a single turbo were so cheap, more people would be running single turbos.

I don't know what the LG Motorsports setup costs. I do know that it consists of AFR LS1 heads, a big hydraulic roller cam, higher ratio rockers, and a FAST LSx intake with 90mm throttle body. Total cost is probably in the $4,000-5,000 range in the top end. Don't know what they did to the rest of it, although it still has stock bore and stroke (346 CID).

Last I checked, most big single turbo kits with all the required parts were in the same range, but that still doesn't include injectors, intercooler, etc.

I wondered what happened to it.