flamin-roids

Well they finally built a road course out here in Utah. Its going to be about 15 minutes away and about 4.3 miles of track. I'm working on my car as we speak to get it race ready but now I've gotten to the engine and I don't know which way to go. I do plan on racing and I'm afraid if I drop a turbo in that I will get put in a class I can't afford to compete in.

So I can use the S5 N/A engine thats in my car right now or I can pick up a J-spec S5 TII engine for $850 and go from there. My car already has a TII drivetrain by the way. The turbo will obviously be more expensive but I need a somewhat highly modified engine to survive several laps on a track that big. But at the same time I can't afford to keep replacing engines at the same time. I'm not worried about horsepower or 1/4 mile times. Just want to build a reliable engine that will keep me competitive.

I can have my engine ported, balanced, rebuilt, with all the fixins for about $2500 (most of the work i can do myself and it really doesn't need to be rebuilt.) Not to mention backup N/A engine parts will be cheap and easy to come by. So thats the way I'm leaning. Can I get some insight on this?

liv

personally i would go n/a

How many turbo cars have you driven though

if you havn't driven one it will take a while to get used to controled driving while on boost especially with a heavily modded turbo engine

flamin-roids

I've driven a few turbos but mostly N/A. I appreciate the response and sound of a N/A compared to the power of a turbo. A highly modified turbo would be a handful on the track but I still need to have enough power to be competitive.

liv

I just think a n/a would be best on a road type track

you could strip it down to weigh nothing and with a stiff suspension handle like your on rails

BoostedRex

As much as I prefer forced induction, I think I'd have to recommend N/A to you. If you are on a tight budget then you'd probably be better off with N/A. And I have seen several cars do very well in the local AutoX circuit with N/A FC's. Just do what liv said and lighten the car up as much as possible and get a great suspension. You'd be amazed how fast you'd be on a road course with a properly set up suspension and a nicely ported N/A motor. Just my .02

Zach

Ocelot

If you want to be competitive, i'd go with NA but on a 1st gen that can be gutted and made much lighter.

flamin-roids

Yeah but it won't handle quite as well. And it would be a huge pain in the ***.

Eternal_Gamer

iTrader: (10)

For you, I'd go N/A first. Its a whole different feel with the turbo boostin. I've had my fun with my 91 NA and 91 Miata with a 1.8. But turbo is what I really want to get into. Its a little bit harder than my miata, but I am getting used to it and I think I am better with it than with my 91NA rx7.

Carzy Driver

start with a 13b N/A and after you go through 10 motors, look into getting a 20b.

Alex6969

an n/a 3 rotor would be a good start, but sadly we all aren't rich and famous

Carzy Driver

you can get cheap 20b's, just got to look in the right places

Syonyk

I'll just speak for the normal forum noise here...

OMG LOL U SHUD GO TURBO MAN IT S FATSTR!1111 NAS R SLOW111

I would agree with the above posts regarding staying NA. You'd be better off spending money (initially) on suspension, brakes, chassis stiffening, etc.

Down the road, as you gain driving experience, you can always swap a turbo drivetrain in.

Also, with a turbo on a road course, remember that the cost of the swap absolutely has to include a bigger radiator, probably an upgraded oil cooler, etc, or you'll fry it quickly.

The S5 NA motor is a nice engine. I would suggest looking at a lightweight flywheel (faster throttle response on shifting), and some form of fuel management - a SAFC-II might be fine for what you're looking to do. NAs run stupidly rich from the factory, and you can gain a significant amount of high end power by leaning it out up high. You also burn less gas running around at high RPM when it's properly tuned.

A good NA, with headers, intake work, minor porting, and a good tune job can push around 200WHP and still be drivable around town. If you go with a bridge port or something more radical, you can make a lot more power without going turbo.

-=Russ=-

bacek

how much money do you have to spend and what type of racing? for endurance type of racing i would go na, but for like time attack things i would go turbo. if you have lots of money i would go na but if you dont have a lot of money i would go turbo. turbo= easier to upgrade, na= more reliable for enduro

Dom_C

this is tough, I love turbo. . alot. . lol but for this style racing I almost think that n/a would be the way to go. A nicly ported n/a with some form of tunability. . maybe look into a megasquirt. That coupled with a header back exhaust and a nice cai of some sort and you could make some damn good power. But like everyone else said, do up your suspension as well.
Dom

superstock2

iTrader: (9)

i'd go n/a for a while until you build up some skill, then go with a lightly modded turbo.... and amazing chassis, suspension, and brakes. if you think about it, a turboII lightly done up still has quite a smooth power band and can provide quite a bit more of street/trackable power than a bridge/ periphial port n/a.

AcidAngel7477

iTrader: (16)

i love n/a's....

:AA:

Sideways7

iTrader: (7)

Stay NA and spend the money on other stuff. First, new suspention. If you are serious about racing don't cheap out on the suspention, save until you can get what you want. You can also get a lightweight flywheel, lighter/bigger wheels, better brakes. You will prob want to get Hawk Blue(Front)/Black(Rear) pads for the track. Just make sure you switch them out before you leave the track as they will eat rotors like you won't believe. You can also gut out stuff if you want to.

Rotary_Knight

iTrader: (4)

Just remember when going turbo things are under a lot more stress and the turbo cars can't drive for long periods of time. After awhile you'll start seeing oil temps rise and when that happens all sort of things can go bad if the car isn't properly taken care of.

Like many others have said go NA. I too drive my NA out on tracks and such and love it to death. If you are not worried about emissions porting will help a lot. Also look into getting a carb. cause that will help too, and a good free flowing exhaust of course. Goodluck

Aaron Cake

iTrader: (1)

I'd lean more towards turbo. The torque curve of the turbo engine can't be beat. Much flatter then the NA which is ideal for road racing and autox. High compression turbo is even better.

flamin-roids

Lots of good suggestions. With the suspension I plan on poly urethane bushings and I'm thinking tokico HP's with racing beat springs (had similar setup on FB and loved it) along with sway bars. Not to expensive and streetable. I already have a TII drivetrain and an aluminum flywheel. I want a S5 TII rear end (with viscous rather than clutch pack LSD) with a 4.30 ring and pinion. Hopefully gearing will help out were torque lacks. I've got S4 TII wheels on there now with some nice Toyo's but the rims are god damned heavy and I would prefer a 17 or 18 inch rim with a 40 or 45 tire rather than the 50's that are on it.

As far as brakes I've got some brembo drilled and slotted rotors and I'm thinking of getting steel braided lines along with some hawk pads. I was considering just buying a TII and using that but my car is in superb condition and nothing needs to be replaced. Just upgraded. Its not going to be an all out race car but pretty damn close. Heres what i was thinking as far as the engine.

Street port
550cc injectors with TII fuel pump (or FD)
Pineapple sleeves
smoothed out intake manifold
Microtech or Haltech ECU (bye bye emissions and sensors)
Racing beat header
Engine balancing (9000- 10,000 rpm redline maybe?)
Fluidyne radiator

Hopefully I can pull off 220 rwhp and 2400lbs is not too far off (2640lbs now with lots to spare) and hopefully have plenty of powerband on the engine rather than very little then a whole lot out of nowwhere. I want it to be very balanced and consistant. After all I'm a beginner and I would kill myself or someone else if I had something too fast. just need a well balanced beginner car. Then maybe down the road a 20B widebody FC will be in the works.

Richter12x2

iTrader: (1)

One thing to note, if you're going to be really tearing it up, bigger diameter tires are more expensive, but I've got 17" ADR wheels that I picked up cheap, and according to the spec sheet weigh in at about 15 pounds per. On suspension, I would pick an adjustable strut so that you can tweak your car's dynamics, and stiffer springs for sure. As I understand, the suspension of choice for road course RX7's is Eibach ERS springs, 400 front, 275 rear, with adjustable Koni's, Tokico Illumina's, or GAB. Out of the three GAB was most expensive and Tokico the least by a good ways, Koni's however, are rebuildable, where I don't think the Tokico's are. Further, the Koni's can be swapped from non-adjustable to one or two way adjustable (seperate adjustments for bump and rebound) when they're rebuilt, and being rebuildable also allows for custom valving which is a plus for later on if you get serious. Adjustable swaybars would also be nice - because you can use the adjustable struts to some degree and adjustable swaybars to put more oversteer in or take some out. i.e. car doesn't turn, stiffen up the rear or loosen the front - car turns TOO much, stiffen the front or loosen the rear.

Richter12x2

iTrader: (1)

Oh, and I think the RX7 LSD's are torsen (torque sensing) differentials, which according to everything I've read is superior to the clutch pack differentials. Are the GXL differentials clutch pack differentials?

rotarygod

iTrader: (1)

There are different ways of looking at things when it comes to track run engines. With a turbo you will have a broader powerband and more of it everywhere, even if you had the same peak power. That's the nature of boost. A turbo is more to worry aobut when it comes to reliability and also needs more concern towards cooling. There is alot to worry aobut with a turbo but if done right it can be a real rush. Proper turbo sizing is critical. You don't want to just use any large turbo out there. For track use you need something that comes on boost pretty early and predictibly. You don't want a large turbo that hits ful boost at 5000 rpm and then is just a mad rush above that. That may look fun on a dyno but it isn't the best thing on a track car. Keep power goals realistic and turbo size moderate. There's no need for 400 hp. I know seveal track people who actually run less boost at the track than they do on the street. They don't want boost kicking in midcorner.

Staying n/a is obviously much simpler. There is less to go wrong and less to worry about. It is far less complicated. You don't have the average power though and do need to rely on proper gearing far more than with a turbo. Gearing is important in any setup but a turbo will have the ability to overcome any issues far easier with just pure force. For simplicity, weight savings, and reliability n/a is hard to beat. You'll have to go to far more extremes in engine setup to get the speed up which will also mean more attention to most other areas of the car. With a trubo you could just leave the stock porting and rely on a turbo to do the rest.

I like apsects of both setups. I like the reliability and simplicity of an n/a and the power of a turbo. With more power comes more work and more you need to pay attention to. If you are caught on a budget I'd say stay n/a. Play with suspension setup first. This will make you faster around a track than a more powerful car with a less than optimum suspension. It's also safer and more fun. If you've got the money and ability, do a properly designed turbo system but keep it realistic.

flamin-roids

The FD's are torsen. The S5 LSD's are viscous and the S4's are clutch pack. But thanks for the insight on suspension. I'll start simple and then once I grasp the basics of racing I'll start tweaking the suspension. But some great insight however.