How much horsepower for $1K?

Used turbochargers and high mileage LS motors.

alfadriver wrote:

EvanB wrote: I could be wrong but I don't think it is possible to do a turbo E85 build for $1000. Even a junkyard turbo build would be tough to do for $1k if you want to keep it cool and reliable on track.

Why? Here's why I think it would be cheaper- the engine gets to stay the same. All you need is the JY manifold and turbo. I'm comparing to a gas turbo project, btw. IMHO, if one can do a gas turbo for less than $1k, then an E85 conversion would be less. Both need injector upgrades anyway, what the E85 conversion means is that you don't have to lower the compression. So no pistons need to be changed.

Engine management and injectors large enough handle the E85 would be the most cost.

I wouldn't see why you would have to lower the compression on a stock Miata engine to run a turbo.

If E85 can be done that cheap I would definitely like to know. From what I have read even the 550cc injectors that I have would be to small. And it would be helpful to have a flexfuel sensor.

With just a gas turbo build you would need to address the cooling system as well. A stock radiator may be fine on the street but if you are tracking it the stock one just won't keep it cool.

In reply to EvanB:

The compression change is a very valid debate. If that's not needed, the difference between E85 and gas would be pretty similar. And there are ways of making big injectors out of small ones- some injectors, you can cut the multi hole tip off of, which almost doubles the flow. I used a set like that for our challenge car. Plus E85 only means no need for flex fuel sensor.

As far as I can put together, they should cost almost the same, IF you are not planning on lowering the compression. 9.5:1 is pretty high for a turbo on gas and not direct injection.

One other thing- with E85, it's also possible to eliminate the intercooler.

Cooling system problems, exhaust plumbing, turbo package- all the same regardless of fuel.

An add on- 550cc injectors is about 55lb injectors. T-birsd SC injectors are 36lb injectors, with the tip cut off, they become just about 70lb injectors. These can be bought new for $70/per or less via google shopping.

It's going to be difficult to make it reliable for track work at that kind of budget.

I'd only go FI for a track car if I could make it NA reliable, you can just about do that in a turbo Miata but it takes $$$$$$$$$$$

turbo engines have no torque without boost... the small block(Ford, Chevy, whatever) has torque from the outset...

You're not going to build a reliable track rat Miata with forced induction for $1K. If you're good with the scrounging and fabrication you might be able build a reliable low-200s rwhp street/autox car with that budget, but if you want to track it on a regular basis it's going to cost a lot more than that. Lots of good info on this topic over at the miataturbo.net forum.

I have no idea if it's possible to do a track-day reliable V8 conversion on that budget. I know I couldn't do it. :)

If I had a $1K budget for more power and I wanted a reliable track Miata, I'd look at a mild NA build. Some combination of a VVT motor, megasquirt, E85, EUDM intake, header, mild head work, etc, and aim for something in the 140-160 range.

codrus wrote: If I had a $1K budget for more power and I wanted a reliable track Miata, I'd look at a mild NA build. Some combination of a VVT motor, megasquirt, E85, EUDM intake, header, mild head work, etc, and aim for something in the 140-160 range.

And even if you already had the VVT engine, $1k would not get that done unless you can do the headwork, build a quality header/exhaust, etc.

turbo engines have no torque without boost... the small block(Ford, Chevy, whatever) has torque from the outset...

Excuse me? Maybe you mean TINY turbo engines have no torque without boost.

Vigo wrote:

turbo engines have no torque without boost... the small block(Ford, Chevy, whatever) has torque from the outset...

Excuse me? Maybe you mean TINY turbo engines have no torque without boost.

The thread is specifically talking about Miata engines, so it's safe to assume that's what his intention was. Geez.

z31maniac wrote:

codrus wrote: If I had a $1K budget for more power and I wanted a reliable track Miata, I'd look at a mild NA build. Some combination of a VVT motor, megasquirt, E85, EUDM intake, header, mild head work, etc, and aim for something in the 140-160 range.

And even if you already had the VVT engine, $1k would not get that done unless you can do the headwork, build a quality header/exhaust, etc.

That's why I said 'some combination of'. Depends on how good you are at scrounging parts, and how good you are at DIY fabrication. If you're not good at either of those then you're not getting a junkyard turbo or V8 swap either!

Brand new, off the shelf, bolt-on parts, $1K will buy you maybe 10 hp on a Miata.

The thread is specifically talking about Miata engines, so it's safe to assume that's what his intention was. Geez.

I guess it's safe to assume that even though you would consider a complicated v8 swap, there is absolutely no middle ground between under 1.8L and over 5.0L? A good running 3.0 would feel VERY torquey in a miata. The whole non-turbo engines lack torque thing stops making sense somewhere between 2.5 and 3.0 liters in a miata, imo. It's being used as a pro-v8 statement when it applies to lots of options that aren't v8s as well.

Money and time are the same thing. If you don't spend one, you have to spend the other. The GRM Challenge is the shining example here, and of course there's been a V8 Miata on the top step of the podium.

Why nothing mentioned between 1.8 and 5.0? Because it's going to be just as much effort to put in a 302 as anything else that wasn't intended to be in there.

If it were me, I'd go with the V8 swap. You'll spend more time fabricating than you would with the turbo, but less time dealing with engine management and you'll have the chance to upgrade everything at the same time. The Ford option is a pretty well-trodden path, and you can get ratty Fox-body Mustangs for pretty cheap. Go with a carb'd motor and the wiring is ridiculously simple. Plus future power upgrades are pretty easy.

One thing to remember is that there's a difference between a fun track day car and one that's being wrung out like there's a million bucks on the line for FTD. The Miataturbo guys don't always realize this, that it's possible to have a bit of mechanical empathy, go a few percent slower and have just as much fun without the carnage and wrenching.

oldeskewltoy wrote: turbo engines have no torque without boost... the small block(Ford, Chevy, whatever) has torque from the outset...

On the track that's irrelevant, the car's never going to fall below 3500-4000 RPM anyway. With a reasonable size turbo (say a 2554 or 2560) that's easily enough RPM to get good boost.

Keith Tanner wrote: One thing to remember is that there's a difference between a fun track day car and one that's being wrung out like there's a million bucks on the line for FTD. The Miataturbo guys don't always realize this, that it's possible to have a bit of mechanical empathy, go a few percent slower and have just as much fun without the carnage and wrenching.

Perhaps. I'm driving mine at more a few percent slower than the bbundys of the world, and yet I'm still only 2 for 4 in terms of having it in running condition at the end of a Miatas @ MRLS event. :)

Keith Tanner wrote: One thing to remember is that there's a difference between a fun track day car and one that's being wrung out like there's a million bucks on the line for FTD. The Miataturbo guys don't always realize this, that it's possible to have a bit of mechanical empathy, go a few percent slower and have just as much fun without the carnage and wrenching.

I do not understand what you're saying here. The only way to get around having brakes that can handle the heat and a cooling system that can handle the heat is to drive slow, on purpose. I dont know about you, but I'm slow enough as it is, and if I have to drive even slower on purpose to make the car not break then I might as well just stay home.

There's a reason I trailer my car to auto-xs that are 20 minutes away from where I live, I want to be able to drive it 10/10ths and not have to worry about how I'm getting home if I break a FLCA or an axle. And there's a good extra 20 pounds in my car already of, "this part is overkill, but you can't win if you're broken". Intentionally driving slow to save the car is not an option.

If you're competing, you don't win by breaking the car.

If you're lapping for fun, you don't have fun by breaking the car.

Not everyone understands this, that it's sometimes better to drive within the car's limits so you can continue to have fun or compete. Sure, it's best to have a car that's completely bulletproof. But if the options are don't drive because the car can't stand it or drive with a bit of sensitivity to your mechanical steed, it seems to me the latter wins every time.

I see this with the kids who come to our local track days. They don't want to come until they've worked through their complete potential mod list, the car has to be absolutely perfect. But you don't get any seat time sitting at home. Meanwhile, for our last track day my car was broken. Did I stay home? No. I brought out the MG. The brakes aren't built for track use and the handling isn't sorted yet. But I had a good time and learned a bunch. If I'd brought out my street Miata, there's a good chance I would have had to drive around an under-specified cooling system. No problem, shift a bit earlier and concentrate on maintaining speed instead.

For a thousand bucks, you're not going to build an invincible car. But you can build one you can have fun with as long as you accept that it will have some limitations. That's my point.