'87

[SaabJohan]

To make this a little easier I have three questions:
How much power did you have in mind?
How much money do you want to spend?
Power vs reliability?

[AEstud]

500-600 hp
4-5k
both if possible;if not then reliability.
:bandit:

[fritz_269]

Originally posted by SaabJohan
By taking a look at the statistics of long races (Like LeMans 24h race) you will found there is more cars with naturally aspiranted engines than turboengines that break because of engine failure.

I'd like to challenge your assumption with some facts:
Here are the number of finishers of the 24 hr Le Mans with turbo (tb) or natural aspiration (na):
1991 5tb / 7na
1992 10tb / 18na
1993 19tb / 11na
1994 12tb / 6na
1995 11tb / 9na
1996 13tb / 12na
1997 11tb / 6na
1998 15tb / 8na
1999 9tb / 13na
2000 9tb / 18na
2001 14tb / 6na
So, over the last ten years, out of 242 finishers, 128 have been turboed cars and 114 have been NA cars. That's a 3% difference. Not exactly overwhelming evidence. I would go a step further and say that the guys who build and drive the Le Mans course probably know a hell of a lot more about engines than either of us; and if there was any concrete advantage to using FI over NA, there wouldn't be any NA cars entered! But the field continues to be evenly split, as do the final standings.

Turbo cars develop much higher peak cylinder pressures, leading to the need for much stronger (i.e. heavier) "parts" to withstand the load - just as larger displacement NA engines must have stronger (heavier) parts to withstand the load of more reciprocating mass, as you pointed out.

Maybe if I put it this way: If an engine produces X amount of torque, the parts must be able to withstand X amount of torque. The crankshaft doesn't care if the torque is being created by high cylinder pressure or just lots of cylinders - all it knows is that it is being torqued by X amount.

- above data culled from the "Le Mans Register" http://user.tninet.se/~aiq291w/

[texan]

Let's also note that the majority of Le Mans non-finishers are not due to engine failures, but a myriad of other problems. Transmission failures and electrical issues are some of the most prevalent problems I've seen in recent years, aside from the plain old crashes that destroy everything.

[SaabJohan]

texan: that is true. But that doesn't matter if we are just talking about the engines.

fritz_269: You're probably right about that. But the count isn't how many that have finished, it is how many that did not finished beacause of a broken engine. I know that when McLaren choosed an engine type for the GT car F1, they wanted an engine with fast response. So it isn't only about reliability, it is also many other factors when the manufactors choose an engine.
That turbo engines are more reliable is according to Garrett which develop some of the turbochargers used in LeMans. And like you said "the guys who build and drive the Le Mans course probably know a hell of a lot more about engines than either of us".

[SaabJohan]

Originally posted by AEstud
500-600 hp
4-5k
both if possible;if not then reliability.
:bandit:

It is possible, but I don't think it is recommended because of the reliability.

For that power a would go for a B23 or B21 engine block. Both 16 and the 8 valve top can be used, but tuned of course. A GT40 or a T04E Garrett turbo can be used, of course you can use a diffrent one if you want but these have been tested on volvos with good result before. If you're going for 500-600 hp you will need new conrods and pistons, and that costs around 1.5-2k.
Maybe the most important is to find a good engine managemant system, both Haltec E6K and E6A have been used with good results. The Autronic SM2 or a MoTeC system can olso be used, these are often a little more expensive. The original Volvo ECU can be used but it must then be modified and this costs money, it is also more difficult to do and it doesn't give the same results.
Instead of the original head gasket I recommend you to use a solid coppergasket with o-rings, these are used in top fuel dragsters and can withstand very high pressures.
The differential must be changed or modified, the gearbox must be changed (I recommend the getrag box), you also need better enginemounts.

Send a e-mail to TTR (link in previous post), they know what to do.
If you want I can send you some pictures of when they build a +400 hp 8 valve engine.

[fritz_269]

Originally posted by SaabJohan
fritz_269: You're probably right about that. But the count isn't how many that have finished, it is how many that did not finished beacause of a broken engine.

I agree that would be a better count, but I'm not sure you could really do that without detailed analyses on exactly why the engines failed. If you suck in a rock, it is listed as "engine failure", but that really has nothing to do with whether you're turboed or not.

I know that when McLaren choosed an engine type for the GT car F1, they wanted an engine with fast response. So it isn't only about reliability, it is also many other factors when the manufactors choose an engine.

Absolutely true. It's always amazing to me that you get anwhere from tiny 3.0L I6 engines to MASSIVE 8.0L V12s - all competing on the same field. It says there's a lot more to road racing than just peak hp.

That turbo engines are more reliable is according to Garrett which develop some of the turbochargers used in LeMans. And like you said "the guys who build and drive the Le Mans course probably know a hell of a lot more about engines than either of us".

Well, I would think Garrett would have a rather vested interest in claiming the superiority of turbos, so I'm not about to take that as gospel truth. Although the field of turbos did do particularly well last year. I honestly believe that, on average, it's pretty split down the fence - you can build reliable power with or without a turbo - you just gotta know what you're doing.

[SaabJohan]

I'm sure that Garrett have done a properly investigation of this before they do statements like that, even if they probably want the show turbos like more reliable.

There is guys who run with V8 engines that agrees to that turbos are more reliable, or at least agrees to that the V8 engines takes a little more work between the races (streetrace or dragrace).

Of course there is more or less reliable engines of both types.

[Someguy]

There are also guys with V8s who are sure and say they were analy probed by aliens. And I'm sure the guys running NA Le Mans cars "know a hell of a lot more about engines then both of us" also.

But anyway my friend has a Volvo/302 conversion and it a hell of a lot of fun. I forgot where he had it done, but its a very clean installation. Everything looks and works like stock, but of course the car is a lot faster. That said there is nothing in principle wrong with building a turbo 4 either besides maybe some practicality. Volvo parts are expensive in the states and there aren't that many places that do routine stuff, much less Volvo speed shops.

But anyway, there are some odd perceptions going on here. For example:

To get the same power from the naturally aspiranted it must rev higher or have a bigger volyme than the turbocharged engine which force air into the engine instead.

5.0 (well 4.96) is bigger then 2.3... So...

If the engine is bigger, its moving parts will get heavier which cause more stress on the parts. This cannot be solved by making them stronger because this will make them even heavier. Of course the use of exotic materials can make them stronger and lighter, but this is very expensive and can also be used in the turbo engine.

Uh... Okay lets think about this for a second. The engine internals of interest here are the rods, pistons, rings, crank, and bearings. So imagine we have too engines, a NA V8 and a turbo 4, both making roughly the same power and torque. "Roughly" since the power curves will most likely be very different.

The rods, pistons, and rings, of the V8 will most likely be LIGHTER (part for part) and LESS STRESSED then the turbo 4 by far. Think about it. The V8 has 4 cylinders fire per rev and the 4 banger 2, so to make the same torque a little less then twice as much energy has to transferred though the rods and pistons of the 4 then the 8. Also there will be much more pressure on the rings of the 4.

But what about:

If the engine is bigger, its moving parts will get heavier which cause more stress on the parts.

The over all mass of the V8 will be greater, but that actually has no effect on how strong or heavy the rods and pistons need to be. All they care about is their own mass and the force exerted on them which is no more then what the turbo 4 would exert.

Of course the use of exotic materials can make them stronger and lighter, but this is very expensive and can also be used in the turbo engine.

I'll give you an example. For my car to safely make 750 hp and turn 7750 RPMs I would need a set of forged rods and pistons, which would cost me about $1100 for the set which is made out of "exotic materials" such as steel and aluminum. To make 1000 hp I would need billet rods, which would push the total up to about $1700. And my car is considered "horribly expensive" by American V8 standards. Equivalent parts for a 302 run about 2/3 that's price.

The Le Mans example isn't a good one either when talking about street cars. What gets most street cars is the repeated cold starts, short trips, idling in traffic at lights, and accumulated wear over time, not full throttle running. For the first three its probably about an even toss up between the turbo 4 and the V8. For the last the V8 has a big advantage. Most V8s cruise down the highway at <2000 RPMs, and rarely go above 3000 RPMs in any normal driving since they don't need to rev to get into their power bands.

Also if you look at the most common causes of severe engine failure in order, blown head gasket, burned piston or ring, bent rod, faulty bearing. The first 2 are very related to combustion chamber pressure which will be much higher in a turbocharged car then a NA.

I'm not saying a turbo 4 is going to be unreliable or a bad choice. I'm saying that if you think a 302 or V8 is going to be unreliable then you have a lot of explaining to do to the tens of thousands (hundreds of thousands?) of people that are driving around in 35, 40+, year old V8s.

[SaabJohan]

A bigger engine have heavier parts. It's not hard to understand why.

These "V8 guys" are proffessionals.

A streetcar with turbo is built to have high torque on low revs, they use small turbine houses. They can then have high pressure on low revs but in high revs low pressure. An 2 litre engine with turbo can for an example have under 300 hp at say 5500 rpm and have torque of over 500 Nm at 2000 rpm.


I copied this from www.egarrett.com

TURBOCHARGED RACE ENGINES

Turbocharged engines are smaller and lighter.
With a turbo, it takes less engine to make more power. To make a naturally-aspirated engine more powerful, you need to increase its capacity and its bulk.

Turbocharged engines are easier to regulate power.
Engines are constantly evolving and becoming more powerful, sometimes at the expense of driver safety. For the racing sanctioning body concerned with safety, Controlling the speed of a turbocharged car is as simple as reducing the turbo's boost. A naturally-aspirated engine, on the other hand, must be drastically re-engineered when the horsepower it generates becomes excessive.

Turbocharged race engines are less expensive, and more reliable.
Turbocharged engines don't have to rely on exotic, expensive materials to reduce reciprocating mass. As naturally-aspirated engines become larger to increase power, the stress due to the necessary increase in engine RMP and increased reciprocating mass placed on their various components also increases.

Turbocharged engines are quieter.
The turbocharger on an engine acts as a natural muffler, minimizing engine noise and providing a more spectator-friendly environment at the races.


...otherwise try contact Garrett I'm sure they will have a really good explanation.

[texan]

SaabJohan- It must be very nice to ignore all the reasons to build NA engines instead of turbocharged ones, which would make perfect sense if all or even the majority of race motors were turbocharged. However they aren't, and the HUGE mass of information supporting why NA engines are in some cases better than their turbocharged brethren must be nice to overlook when considering your viewpoint. There are of course very good reasons to build one or the other, which mostly rest on current states of engine development within a given factory and secondly on racing rules for a given class of competition. Luckily for you, there's no such reasoning to deal with here. If Garret (a company which only produces turbocharger hard parts) says turbos are better, you can conveniently ignore all other information, race results, mechanical engineering data and common sense in proving that turbo engine are by nature better. And further, that ANY turbo motor is by definition better than ANY NA motor, regardless of what they were originally designed for. How nice, I wish I were you and also a race engine builder, it would make life much simpler in winning against those inferior NA oriented people. Again, I give up.


Ps- There are pros and cons to both designs, this isn't a new argument. And since it isn't, one might assume that because those damn dirty manufactuers continue to build race winning NA motors, they might have a reason for it. For anyone with a more open mind, it could be easily recognized that which is better depends upon many factors for any given situation, and not something as simple as one typically slanted point of view from one manufacturer of only one product. But that probably makes no real sense, does it?

[texan]

OK, that came off pretty harsh. I apologize, I'd had a few last night .

Besides, why do we keep talking about big V8 engines and turbo engines as though they are mututally exclusive? You can turbo a big motor just as easily as a small one, and ultimately the power ceiling is a lot higher with the bigger motor. After all, Dutweiler's last big buildup was a 2,000+ hp small block Chevy displacing 427ci (about 7.0L).

[SaabJohan]

Actually Garrett doesn't only produce turbochargers. Garrett is a part of Honeywell.

All engines can be turbocharged, small and big, twostroke, fourstroke or rotary engines.
But for dieselengines it's probably the only way.

And I would like to add that turbo vs NA is only generally, not between a turbo and NA engine.

[texan]

Garrett, the company, produces turbochargers. That's it. Regardless of who owns them, that's what they make. Honeywell produces thermostats and humidifiers, is Garrett an epxert in the air conditioner field too? No, Garrett makes turbos, that's it. Garrett's product page lists nothing other than turbos.

Let's drop this ridiculous arguement, after all we are talking about a street car and not a race car. If you want to spend the money to build up an old inline 4 cylinder turbo motor to make a ton of power, fine. Likewise, if you'd like to swap in a much larger motor and possibly build that up for serious power, that's also great. My recommendation is to start with the larger motor, which as a point of fact starts out with greater power output and I also feel will end up with greater power output, but that's just one man's opinion. At any rate, I hope you have fun with the car after it's all done, peace.

[Someguy]

Texan, I don't think you were only one to have a few last night:

And I would like to add that turbo vs NA is only generally, not between a turbo and NA engine.

Huh?

Yeah, well, anyway. Good luck on your build up. I'm going to go see if I can't get me one of them European turbocharged beers from the fridge. They are much better then those American NA beers that you have to drink 8 of just to get a buzz.