turbo or 24v swap?

[Jb325is]

I think you guys are going too deep into this. It's not necessarily a result of any one component, its just heat. The amount of heat generated on track is already so much more than you can possibly generate on the street, adding a turbo makes it that much worse. The failures that happen on track with turbo cars are almost always heat related, and cannot be duplicated in any other scenario. I haven't tracked an m20 turbo race car, so I can't speak directly towards that, but I have spent more time than most at race tracks over the years at various levels of competition and I can tell you that aftermarket turbo cars are not reliable. They work alright for time attack, where you're running a couple hot laps and putting it up, but for a DE/Club race car your odds of running 5 30 minute sessions in a day in the summer time down here in the southeast without issue are pretty slim.

I will say this also applies to high strung N/A motors as well. Pretty much anything that people mess with sucks. Which is why I recommended the 24V, put a stock motor in the car with some good shocks and sticky tires and you should be able to run all day in a car that almost no one on this forum can run to it's full potential.

[agent]

...why I recommended the 24V, put a stock motor in the car with some good shocks and sticky tires and you should be able to run all day in a car that almost no one on this forum can run to it's full potential.

Completely agree.

Or just go full ham and put an LS in it.

[redsubdivisions]

Completely agree.

Or just go full ham and put an LS in it.

Oh boy. I smell thread derail very soon.

[TobyB]

Any engine making a high specific output is at risk if it goes lean. You can't just go comparing an understressed 170hp lump which can run lean all day to a high strung turbo engine and tell people turbos are bad because you'll blow the turbo engine up if it goes lean. If you're going to compare you have to compare like things. Whether you're making 150hp/l turbo or NA, you're endangering your engine by going lean under load.

This is all very true. But even a stock M20 can't do a whole track day running much leaner
than 13.7:1 at WOT. The stock 24v with all the tuning, care, and parts that the
factory provided stands a better chance than a homebrew turbo.
A carefully tuned .75 bar turbo, with good plumbing, tested cooling, etc. should be
just about as durable. If it has oil squirters, pistons with good ring lands, yadda yadda. And it's been tested, debugged, retested, redebugged, etc.

The track is a cruel mistress. Everything you haven't tested will fail. Many things you
HAVE tested fail later anyways (because you didn't test them for a whole season).

Experientially, the turbos are fragile on track. Even the local 928 race car guy now has an LS(X) under
his hood- and he's been a LOT happier this season. AND he's a Porsche guy.
A.N.D. he's been doing this for 10+years.

But it sounds like the OP's going turbo, so...

t

[varg]

And now because of that, a different digression, I'd go with an LS over any 24V BMW I6 any day. Power I dream of for my M20 Turbo plans, but in understressed bone stock form. Now that's durable.

[craiggroves91]

And now because of that, a different digression, I'd go with an LS over any 24V BMW I6 any day. Power I dream of for my M20 Turbo plans, but in understressed bone stock form. Now that's durable.

I think you missed the OP. He is doing 24v or turbo m20. A stock or nearly stock 24v will be making less power or the same power as a Los boost turbo m20 all while being under less stress and more reliable, especially if it has low mileage and is overhauled before installation. You've been comparing a built m20 and a turbo m20 making the same power...this isn't what is being compared here.

Still stands that an N/A 24v will be more reliable than a turbo M20 and most likely at a cheaper price.

These top of the line turbo parts and tuning you speak of would cost more than a 24v engine. I spent 3k on a built for turbo m20 with all top of the line parts. Then still needed an ignition setup, engine management, intercooler piping, exhaust, a proper tune (which is far from cheap from a reputable shop), cooling system, etc. Yeah, the setup I was working on would have made more power than s52, but it was going to cost much more and wasn't going to be as reliable. It's something every car guy knows, a turbo is another factor you have to deal with. It's naïve to say it would be as reliable or more reliable than a 24v.

We will probably just have to agree to disagree here.
I know a well built low boost m20 can be very reliable, but it won't be AS reliable as a 24v.




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[haaken675]

But it sounds like the OP's going turbo, so...

t

Not necessarily. I am weighing my options so far. I think I can mechanically make a low boost turbo car work on track with lots of cooling mods. I also love the idea of the 24v swap as I had 2 e36's and love those motors....I am having the hardest time finding motors locally, so that is pushing me more towards a turbo at this point, but IDK...probably will decide the next commission check I get which direction I go.

[redsubdivisions]

I'm really surprised this thread didn't end with a "do some research and you can figure it out" type of statement.

Look, everything is going to have its advantages and disadvantages. I don't regret my turbo M20 one bit considering how well it has held up for me, but I also took the time to make sure things were done properly. My very first car I boosted was an S13 KA24DE powered 240SX. That didn't last very long and it was an expensive lesson.

Regardless of what route you take, do it right or do it twice. In the meantime, if you ever want to see my setup, I'll be happy to show you if I'm ever social again. lol

[haaken675]

I'm really surprised this thread didn't end with a "do some research and you can figure it out" type of statement.

Look, everything is going to have its advantages and disadvantages. I don't regret my turbo M20 one bit considering how well it has held up for me, but I also took the time to make sure things were done properly. My very first car I boosted was an S13 KA24DE powered 240SX. That didn't last very long and it was an expensive lesson.

Regardless of what route you take, do it right or do it twice. In the meantime, if you ever want to see my setup, I'll be happy to show you if I'm ever social again. lol

I am surprised the thread didn't turn into that as well...Especially since I made the first post after drinking. I do think I at least answered one key question on why I couldn't find much info on tracked turbo m20's.

And I definitely appreciate your offer. If I am down your way in the near future I'll send you a message!

[digger]

if youre not after that much hp just swap a nice 24V for OEM reliability and be done. if you like ongoing projects get an m20 haha

[ak-]

Are you serious right now? Any tune that is within a million miles of halfway decent has this little thing called overboost protection. Boost hits a preset point? It cuts fuel and spark. No damage. You set overboost protection to a safe level, and you can weld the wastegate shut and never damage the engine by overboosting, it'll just cut out as soon as the boost reaches the overboost threshold. Your sig says you have a turbo 325is, how on earth do you not know what overboost protection is? I am baffled.

YES, I am serious right now. I do have over boost protection turned on, but I am talking in the spectrum of everything that can go wrong and I do not believe OP has the foundation to be setting every single parameter up to prevent something going wrong on something like a turbo motor that's going to be used on the track. He's a self admitted noob and there is nothing wrong with that except for the uphill learning curve not to break things.
I get it. You love turbo's. They will never be as reliable in home-brew form comparing to it's NA counterpart.

[varg]

I think you missed the OP. He is doing 24v or turbo m20. A stock or nearly stock 24v will be making less power or the same power as a Los boost turbo m20 all while being under less stress and more reliable, especially if it has low mileage and is overhauled before installation. You've been comparing a built m20 and a turbo m20 making the same power...this isn't what is being compared here.

-snip-

We will probably just have to agree to disagree here.
I know a well built low boost m20 can be very reliable, but it won't be AS reliable as a 24v.

Nah, just read the turn the thread took right above my post and you'll see why I mentioned an LS engine. Also read my first post in this thread:

More power is great but it's not strictly necessary for fun on a track. With suspension mods, good tires and light wheels you'll have an excellent momentum car for track days, even if you only have a chipped M20 with a "sport" exhaust.

Building a turbo M20 car capable of taking the beating of a track day is one of my goals, but it's going to be tougher than doing so with a NA 24V engine. The cooling and tune have to be perfect and the stock brakes might not be adequate for the speeds you can achieve with >2x stock power. I'm usually anti-24V because iron block 24V engines add something like 40lbs+ over the nose vs M20s, but it sounds like the better option for you.

YES, I am serious right now. I do have over boost protection turned on, but I am talking in the spectrum of everything that can go wrong and I do not believe OP has the foundation to be setting every single parameter up to prevent something going wrong on something like a turbo motor that's going to be used on the track. He's a self admitted noob and there is nothing wrong with that except for the uphill learning curve not to break things.
I get it. You love turbo's. They will never be as reliable in home-brew form comparing to it's NA counterpart.

I don't love turbos, I've been in the turbo world for a while and I know they're cheap power (fits my student's budget) and through trial and error and paying attention to people who know more than me, I've come to know what I'm talking about. I know how to do it wrong and cheap and make it work, and I know how to do it right. I've tuned my shoestring budget cars, and I've tuned cars with fully forged engines with custom equal length twin scroll manifolds that cost more than my entire setup. No turbo car worth a shit doesn't have overboost protection so overboost is probably the worst example I can think of of turbos blowing engines up. If it doesn't have overboost protection the tune is automatically complete shit because it's unsafe, that has nothing to do with the turbo, it's just an awful tuner. Read my earlier posts, I flat out said cobbled together crap like my car is not reliable, it has to be done properly (somehow my car never leaves me stranded though while stock cars are blowing up ). I never claimed an aftermarket turbo setup done poorly is reliable. I said the opposite; do it right and it will be fine.

[Zacm829]

I'll echo what other have said. Turbo cars are less likely to finish a hard track session. I've seen it before usually is heat related. I'd say toward an engine swap. Much more linear power delivery for track duty. V8 swap gets my vote!

[djjerme]

Any kind of Forced Induction is going to have some issues on the track..

Even the bone stock turbo setups have issues on just track days. My buddy had to replace the turbo already on his 1M after a single track day. Granted, he does fall in to that category of being a far better driver than even I in my own race car, but he says it's a common problem on the 1-series M.

Currently, he and I are building two new E30 based race cars to run in ST class, which is strictly a Power-to-weight class. We are approaching each build differently, but the key is reliability and the ability to run 1 hour or longer enduros.

Reliability and consistancy is the name of the game. As well keeping it simple. So forced induction is simply not a viable option at this point. Instead, his motor (which is done already) is a stroked M20 with the RHD kit, ported head/cam and a stupid light '83 316 shell. My car, the plan is 24v swap and then lighten the hell out of it.

The options I have available (depending how much I want budget) is all-aluminum M52 that needs a rebuild, S52 out of another race car, or track down a M54.

While I would love the power a turbo'd M20 would offer, dealing with the heat for longer races is just too much within these chassis. Like I said, if cost was no object, then I could spend the money to make the turbo work, but then I would be spending more than the car is worth, and I could've started with something better for racing.

[haaken675]

Any kind of Forced Induction is going to have some issues on the track..

Even the bone stock turbo setups have issues on just track days. My buddy had to replace the turbo already on his 1M after a single track day. Granted, he does fall in to that category of being a far better driver than even I in my own race car, but he says it's a common problem on the 1-series M.

Currently, he and I are building two new E30 based race cars to run in ST class, which is strictly a Power-to-weight class. We are approaching each build differently, but the key is reliability and the ability to run 1 hour or longer enduros.

Reliability and consistancy is the name of the game. As well keeping it simple. So forced induction is simply not a viable option at this point. Instead, his motor (which is done already) is a stroked M20 with the RHD kit, ported head/cam and a stupid light '83 316 shell. My car, the plan is 24v swap and then lighten the hell out of it.

The options I have available (depending how much I want budget) is all-aluminum M52 that needs a rebuild, S52 out of another race car, or track down a M54.

While I would love the power a turbo'd M20 would offer, dealing with the heat for longer races is just too much within these chassis. Like I said, if cost was no object, then I could spend the money to make the turbo work, but then I would be spending more than the car is worth, and I could've started with something better for racing.

What kind of power is he expecting with the RHD kit and the stroker motor? not opposed to building the M20 for n/a if it will give me the power I want...I know I don't need tons of power on the track to have a killer time, but for a car that will spend most of its time on the roads, I would prefer some decent power.