L28ET not reliable as a endurance track car

[turbogrill]

Hi,

 

I do endurance racing with my 280zx, ususally it's 8 hours of nonstop racing. It but a lot of wear on the car, 1 hour of racing causes equal wear to 1 year of modest street driving (my own non scientific statement).

 

Anyway, our L28E has taken A LOT punishment and is holding up surprisingly well. But it's a little low on power (planning a L28E build with more oomph).

(We are not expert drivers or expert mechanics, that probably doesn't help).

 

A lot of endurance racing teams stay away from turbos because it's just more shit that can break (and everything can break)

 

1. Is the L28ET considered as reliable as the L28E?

 

2.Is there any known weaknesses about the L28ET?

 

3. Could being at constant high RPM and at constant high temp cause any issues for the L28ET?

 

I have spoken to a team that had a L28ET, took them a long time to get the car reliable and would not recommend it. Curious what the experts over here as to say!

 

Also, it needs to be reliable on a budget. We can't afford to rebuild the engine after 8hours of racing....

[grillhands]

I would think an oil cooler and a really efficient intercooler would help. Also MEOH spray for further cooling. Perhaps coolingmist.com

[softopz]

The l28et has very low compression and was "overbuilt safety net" compared to most common turbo engines. I dont see why a decently built l28et running 10-13psi intercooled 8 hours shouldnt be a problem with a proper tune. ARP hardware  not a must but would be good at those extremes and stay from felpro headgasket OEM for head and manifold.

[turbogrill]

Thanks!

 

That is some good input. My plan was to go turbo but I got scared from peoples stories about everything exploding all the time....

[Chickenman]

As mentioned above, cooling is going to be your biggest concern, As well as running a GOOD oil cooler ( Setrab and Earls make some fine units ). Edit: Use a decent quality Intercooler, but be careful to not go too big as you don't want to radiator air flow.  Low pressure drop as well. Some other points to consider:

 

1: Get a custom aluminium radiator with a thicker core. You can't have to much cooling on a track car. Add ducting in front of the radiator to force all inlet air through the core. Use Water Wetter by Redline ( it really works ) or DEI's product. You don't really need a fan, but you may want to run an electric puller fan for keeping engine cool in pits when tuning etc.

 

2: Exhaust heat control. Ceramic coat the exhasut manifold on the outside. Ceramic coat the outside of the exhasut Turbine housing and/or run a Turbo blanket around the Turbo exhasut housing. Ceramic coat the inside and outside of the down pipe. I do not like heat wrap as it causes fairly rapid deterioration of the exhasut piping due to heat retention. Ceramic coatings ( particularly on the inside of the down pipe ) are a much better solution.

 

Some guys like to Ceramic coat the inside of the exhaust manifold and exhasut Turbine housing. This can be very tricky with the exhasut manifold, as it can be hard to properly clean and  prepare all the crevices and corners in the manifold. Any bit of coating that comes loose can damage the Turbine exhasut impeller.  I prefer to use ceramic coating on the inside of the exhaust system ONLY post-Turbo

 

3: Pay particular attention to insulating all of the brake lines and wiring on the Turbo side of the engine. Make sure that ALL brake and clutch piping is insulated with a goof quality heat reflective wrapping.

 

4: Make sure that the brake master cylinder has a good heat shield. The 280ZX has a factory shield and I would consider upgrading that. Some gold leaf reflective foil on the outside of the factory shield, or a custom made shield, would be a good start. Consider putting a Naca duct in the Access panel for the Master Cylinder. This will draw cooling air from the outside and allow it to flow over the Brake and Clutch master cylinder. You need some airflow in that area to cool things off.

 

5: Water/Methanol injection is always a good idea. Even with fairly low boost pressures. Detonation is your enemy in any Turbo engine, and the Piston ring lands are the weakest point.

 

6: Forged pistons designed for a Turbo engine are always a good call. They are much stronger than cast pistons overall, and particularly in the ring land area. Custom Turbo pistons will have the ring lands moved down from the combustion chambers  to reduce some of the thermal shock loads and will have thicker ring lands to make them stronger. The piston crowns are also made thicker to better handle thermal loads and shock loads ( detonation ) If the budget and rules allow it, get some proper forged pistons from Ross, Wiseco, CP etc.

 

If you decide to stay with the factory Turbo cast pistons...go conservative with Boost and Ignition advance. Detonation MUST be avoided with cast pistons. If re-using the old pistons. Get them professionally claened, measured and crack checked. Again, the ring land areas are the places that get pounded out of spec and subject to cracking.

 

7: Keep the revs down. Turbo cars don't need a lot of RPM's to make power. I'd consider a shift point of 6,000 to 6,500 RPM MAX... if using stock bottom end components. Use new ARP hardware for Rod Bolts ( preferred ) or new factory 9MM bolts. NEVER re-use the stock rod bolts in a Race engine.

 

Hope some this helps and gets you some trophies. GL !!

Edited January 28, 2017 by Chickenman

[grillhands]

Well said!

[turbogrill]

As mentioned above, cooling is going to be your biggest concern, As well as running a GOOD oil cooler ( Setrab and Earls make some fine units ) use the largest intercooler that you can. Low pressure drop as well. Some other points to consider:

 

1: Get a custom aluminium radiator with a thicker core. You can't have to much cooling on a track car. Add ducting in front of the radiator to force all inlet air through the core. Use Water Wetter by Redline ( it really works ) or DEI's product. You don't really need a fan, but you may want to run an electric puller fan for keeping engine cool in pits when tuning etc.

 

2: Exhaust heat control. Ceramic coat the exhasut manifold on the outside. Ceramic coat the outside of the exhasut Turbine housing and/or run a Turbo blanket around the Turbo exhasut housing. Ceramic coat the inside and outside of the down pipe. I do not like heat wrap as it causes fairly rapid deterioration of the exhasut piping due to heat retention. Ceramic coatings ( particularly on the inside of the down pipe ) are a much better solution.

 

Some guys like to Ceramic coat the inside of the exhaust manifold and exhasut Turbine housing. This can be very tricky with the exhasut manifold, as it can be hard to properly clean and  prepare all the crevices and corners in the manifold. Any bit of coating that comes loose can damage the Turbine exhasut impeller.  I prefer to use ceramic coating on the inside of the exhaust system ONLY post-Turbo

 

3: Pay particular attention to insulating all of the brake lines and wiring on the Turbo side of the engine. Make sure that ALL brake and clutch piping is insulated with a goof quality heat reflective wrapping.

 

4: Make sure that the brake master cylinder has a good heat shield. The 280ZX has a factory shield and I would consider upgrading that. Some gold leaf reflective foil on the outside of the factory shield, or a custom made shield, would be a good start. Consider putting a Naca duct in the Access panel for the Master Cylinder. This will draw cooling air from the outside and allow it to flow over the Brake and Clutch master cylinder. You need some airflow in that area to cool things off.

 

5: Water/Methanol injection is always a good idea. Even with fairly low boost pressures. Detonation is your enemy in any Turbo engine, and the Piston ring lands are the weakest point.

 

6: Forged pistons designed for a Turbo engine are always a good call. They are much stronger than cast pistons overall, and particularly in the ring land area. Custom Turbo pistons will have the ring lands moved down from the combustion chambers  to reduce some of the thermal shock loads and will have thicker ring lands to make them stronger. The piston crowns are also made thicker to better handle thermal loads and shock loads ( detonation ) If the budget and rules allow it, get some proper forged pistons from Ross, Wiseco, CP etc.

 

If you decide to stay with the factory Turbo cast pistons...go conservative with Boost and Ignition advance. Detonation MUST be avoided with cast pistons. If re-using the old pistons. Get them professionally claened, measured and crack checked. Again, the ring land areas are the places that get pounded out of spec and subject to cracking.

 

7: Keep the revs down. Turbo cars don't need a lot of RPM's to make power. I'd consider a shift point of 6,000 to 6,500 RPM MAX... if using stock bottom end components. Use new ARP hardware for Rod Bolts ( preferred ) or new factory 9MM bolts. NEVER re-use the stock rod bolts in a Race engine.

 

Hope some this helps and gets you some trophies. GL !!

 

That is some great advice!

 

Thanks

[260DET]

Don't forget engine management, an aftermarket ECU should be a priority because unless fuel and spark are correctly regulated then the rest is irrelevant, eg the best pistons will fail if fuel/spark are not right. And a tuner too of course who can set everything up during a dyno tune, problem to be solved is that not all tuners are good enough.

[Xander]

I am no racer by any means, but I would approach this differently.

 

Racecars need to be as simple as possible (KISS). And with endurance racing thermal management seems very important indeed.

 

Make the head flow. and keep it under 7000RPM. no fancy pistons needed. Get the engine up to 225-250 hp NA and THEN ad a turbo. run it at 5 psi. No intercooler needed. A intercooler is just another part to fail. Just think of all the connections in the piping.

 

This should get you into the 300-350HP range easy.

 

No expensive pistons, no electric fan (just the mechanical one), no intercooler with a bunch of silicone connectors.

 

This also keeps the weight penalty for adding a turbo down.

 

Maybe I am a crazy but keeping it simple seems like a good idea.

Edited January 27, 2017 by Xander

[turbogrill]

I am no racer by any means, but I would approach this differently.

 

Racecars need to be as simple as possible (KISS). And with endurance racing thermal management seems very important indeed.

 

Make the head flow. and keep it under 7000RPM. no fancy pistons needed. Get the engine up to 225-250 hp NA and THEN ad a turbo. run it at 5 psi. No intercooler needed. A intercooler is just another part to fail. Just think of all the connections in the piping.

 

This should get you into the 300-350HP range easy.

 

No expensive pistons, no electric fan (just the mechanical one), no intercooler with a bunch of silicone connectors.

 

This also keeps the weight penalty for adding a turbo down.

 

Maybe I am a crazy but keeping it simple seems like a good idea.

 

You are wrong from a F1 perspective but from a normal people racing perspective you are absolutely right. Specially when it comes to endurance racing.

Doesn't matter if you have a fast car if you need to spend 20min to fix something, over 8hours racing 20minutes is very hard to catch up on.

 

I thought about the exact same thing, a very low boost turbo on a good tuned engine. Sounds good to me.

 

After reaching 200rwhp I wouldn't spend anymore money on engine, then brakes and suspension gets more important. (Already have a ton of suspension upgrades but it can be better).

Even after reaching >160hp I think driving lessons is probably where we should spend our money...

 

The typical car we need to beat is a E36 325. They have 190hp and similar weight as 280zx and usually good suspension.

 

With the current Chumpcar racing rules a E36 325 can only do ECU, exhaust after header, polybushings and maybe springs. With a 280zx there is a LOT of room for improvements (you can build real race car I think).

[Xnke]

Or you could, you know, look at successful L28ET powered racing cars (real, actual racing cars) and see what they've done and at what power level, and what level of competition.

 

1000+HP L28ET's were run in IMSA racing, even if they did "turn them down" to 700HP for the races. Look at those.

 

You don't need forged pistons. You don't need *any* internal engine upgrades, persay-but rod bolts are a good idea. You don't need a ported head, or a cam, or even a new turbo or injectors for 200RWHP.

 

You Don't need an aftermarket aluminum radiator-the stock ZX radiator cools better, in my experience. Heck, at 300RWHP, I can't get the engine more than 5 or 6 degrees above the thermostat's fully-open temperature, and that's when it's 120 degrees on the pavement. The car with the aftermarket aluminum radiator? 200-210 degrees on the same day, with the same 180* thermostat.

 

To make a 200RWHP L28ET for racing, you need good, programmable engine management-of whatever flavor you want. That's all. Nothing else is *needed* to get to this level of power. They'll run literally hundreds of thousands of hard miles at this level-you'll find the limits of your oil pan before you find the limits of anything else. I'm not talking about a rebuilt or freshly machined engine-I'm saying a stock, 150-thousand-mile motor. There's NOTHING AT ALL wrong with them at this level. Keep the manifold air temperatures down, keep the engine out of detonation, and RUN THE SHIT OUT OF IT.

 

The stock intake manifold will keep you from over-revving it, you'll notice torque falling off at about 5800RPM, and by 6500RPM you'll be shifting up anyway. Every time you rev it over 7000RPM, count that as 1 minute. After 2 hours, change your stock valve springs. They're on borrowed time, even with the stock cam lift.

 

What you'll discover are the limits of the L28ET in road racing:

 

Right off the bat:

Oil pan. It's good to a point-then it'll bite you.

Oil cooler. You need a good one, AND you need a good thermostat for it. The stock ZX auto-turbo one is fine if it's in good shape.

Rod bolts. These might come before the oil pan, but they might not. Also dependent on driver and tune.

Crankshaft Damper. These are *old*. All of them. They'll wear out fast at 7000+RPM, and will be a maintenance item. Get a good new one and check it often.

Crankshaft Damper Bolt. Again, check it often. If it loosens up, the crank damper will start working the crank and shear the key.

Engine management. You need some that can actually be adjusted to suit the engine and usage.

 

220RWHP:

Stock turbo is done. You're out of air.

Stock injectors are pretty much done-maybe 30HP more if your tune is spot on.

The J-pipe is out. Too much heat, too many problems. Get an intercooler on it. Use 18 gauge aluminum tubing, it's a race car, not a nuke plant.

Seriously, intercooler. You'll pick up horsepower AND reliability and the whole setup need not weigh more than 15lbs.

 

350RWHP:

You're gonna want to start looking into ported heads and bigger cams here-you can get here without them, but it's harder on everything.

Good intercooler. Doesn't have to be big, or thick. Does need to be ducted properly. Get it in the airflow and it'll do the job. Cover your whole radiator and watch everything melt down.

Bearing clearances. Time to start doing regular inspections and looking at what kind of clearances, and what kind of oil temperatures you're running.

Cooling system. The radiator is still probably just fine-but you're gonna want to look at the cylinder head cooling thread here to see what to do about keeping all six fire-rings round.

 

400HP:

You *need* forged pistons at this point. The stockers can't hack it at this level, regardless of a good tune.

The stock US-market exhaust manifold is going to be getting pretty tired at this point. It's fine, flow-wise, but the heat will be taking a serious toll on it due to thermal expansion.

 

450+HP:

Beyond here, there be dragons. You're going to run into odd failures at this point. Weird stuff starts happening, and you will need good data and good people to really know what's causing problems, and what's just a symptom of a bigger problem. This is a road less traveled, and the map isn't well marked.

Edited January 28, 2017 by Xnke

[TimZ]

Or you could, you know, look at successful L28ET powered racing cars (real, actual racing cars) and see what they've done and at what power level, and what level of competition.

 

1000+HP L28ET's were run in IMSA racing, even if they did "turn them down" to 700HP for the races. Look at those.

 

You don't need forged pistons. You don't need *any* internal engine upgrades, persay-but rod bolts are a good idea. You don't need a ported head, or a cam, or even a new turbo or injectors for 200RWHP.

 

You Don't need an aftermarket aluminum radiator-the stock ZX radiator cools better, in my experience. Heck, at 300RWHP, I can't get the engine more than 5 or 6 degrees above the thermostat's fully-open temperature, and that's when it's 120 degrees on the pavement. The car with the aftermarket aluminum radiator? 200-210 degrees on the same day, with the same 180* thermostat.

 

To make a 200RWHP L28ET for racing, you need good, programmable engine management-of whatever flavor you want. That's all. Nothing else is *needed* to get to this level of power. They'll run literally hundreds of thousands of hard miles at this level-you'll find the limits of your oil pan before you find the limits of anything else. I'm not talking about a rebuilt or freshly machined engine-I'm saying a stock, 150-thousand-mile motor. There's NOTHING AT ALL wrong with them at this level. Keep the manifold air temperatures down, keep the engine out of detonation, and RUN THE SHIT OUT OF IT.

 

The stock intake manifold will keep you from over-revving it, you'll notice torque falling off at about 5800RPM, and by 6500RPM you'll be shifting up anyway. Every time you rev it over 7000RPM, count that as 1 minute. After 2 hours, change your stock valve springs. They're on borrowed time, even with the stock cam lift.

 

What you'll discover are the limits of the L28ET in road racing:

 

Right off the bat:

Oil pan. It's good to a point-then it'll bite you.

Oil cooler. You need a good one, AND you need a good thermostat for it. The stock ZX auto-turbo one is fine if it's in good shape.

Rod bolts. These might come before the oil pan, but they might not. Also dependent on driver and tune.

Crankshaft Damper. These are *old*. All of them. They'll wear out fast at 7000+RPM, and will be a maintenance item. Get a good new one and check it often.

Crankshaft Damper Bolt. Again, check it often. If it loosens up, the crank damper will start working the crank and shear the key.

Engine management. You need some that can actually be adjusted to suit the engine and usage.

 

220RWHP:

Stock turbo is done. You're out of air.

Stock injectors are pretty much done-maybe 30HP more if your tune is spot on.

The J-pipe is out. Too much heat, too many problems. Get an intercooler on it. Use 18 gauge aluminum tubing, it's a race car, not a nuke plant.

Seriously, intercooler. You'll pick up horsepower AND reliability and the whole setup need not weigh more than 15lbs.

 

350RWHP:

You're gonna want to start looking into ported heads and bigger cams here-you can get here without them, but it's harder on everything.

Good intercooler. Doesn't have to be big, or thick. Does need to be ducted properly. Get it in the airflow and it'll do the job. Cover your whole radiator and watch everything melt down.

Bearing clearances. Time to start doing regular inspections and looking at what kind of clearances, and what kind of oil temperatures you're running.

Cooling system. The radiator is still probably just fine-but you're gonna want to look at the cylinder head cooling thread here to see what to do about keeping all six fire-rings round.

 

400HP:

You *need* forged pistons at this point. The stockers can't hack it at this level, regardless of a good tune.

The stock US-market exhaust manifold is going to be getting pretty tired at this point. It's fine, flow-wise, but the heat will be taking a serious toll on it due to thermal expansion.

 

450+HP:

Beyond here, there be dragons. You're going to run into odd failures at this point. Weird stuff starts happening, and you will need good data and good people to really know what's causing problems, and what's just a symptom of a bigger problem. This is a road less traveled, and the map isn't well marked.

^^^^Xnke FTW - best advice so far^^^^

 

Regarding the exhaust manifold - I don't know what your class rules allow, but I would recommend emulating the Euro manifold's bellows arrangement by cutting the "regular" turbo manifold on the same spots that the Euro manifold has bellows, and weld in simple stainless slip joints - single or double slip, either will work.  This will go a very long way towards eliminating the thermal expansion/warpage issues and you can do a better job of porting the runners if you like.

 

Also totally agree on the intercooler - it's a non-moving part that drastically reduces your tendency to detonate, FFS.  It's not rocket science to get a hose to not blow off a piece of tubing.

Edited January 28, 2017 by TimZ

[Chickenman]

XNKE; Good call on not over-sizing the intercooler. When I suggested the largest Intercooler that you can fit, I had a vision of a reasonably sized one that does not block Rad  flow. Then you made me think of the barn door types that some guys put on and I edited my original post. You need something decent with a low pressure drop.

 

Observation on stock Rad is interesting. If stock ZX rad holds up to Road Racing, that's great. Hasn't been my experience though in other Hillclimb/Road Race cars. I've never found a factory rad that can adequately cool a car used for Hillclimbs or Road Racing. Track days may be a different matter. They are relatively short. I've used Aluminium and custom made copper rads for various Race cars. Thermally, copper does cools better than aluminium. But when you start running thicker cores a copper rad gets really, really heavy. All that weight up front is not good.

 

BTW, I have a custom double core copper rad in my 280Z. I can run the AC on 100 F days at freeway speeds and temp stays rock solid at 185 to 190 degrees. Rad weighs a ton though.

 

What shape the old rad is in plays a big part as well. A 40 year old corroded and leaky ZX factory rad is not worth the time and bother to fix IMHO. If you have a pristine factory ZX rad, well that may be different. But I still stand with my recommendation to get a GOOD quality aluminium rad for Endurance or Road Racing racing. I ( used to ) Hillclimb, and that is EXTREMELY hard on an engine and it's cooling system. High quality aluminium rads prevail as the choice for cooling for all the big HP cars. . Unfortunately, there is some cheap junk out there as well. 

 

Radiators from CR Racing, Griffin  and Ron Davis radiators are top quality but can cost big $$$. A lot of local racers have had good success with Northern Radiators. They make custom rads, with high efficiency cores at a reasonable cost.

 

http://www.northernfactory.com/HIGH_PERFORMANCE

[jt1]

Do some research on member "Mayolives" car.  Turbo L28ET, making 450 at the wheels, and he ran it for 5 or 6 years doing 7 or 8 OT events a year, with no issues.  It was a well done build, and it served it's purpose very well.

[Tony D]

EuroZXT was 20bhp more than US-Spec (180 vs 200) No ECCS just simple pressure retard, vacuum advance E12-80 dizzy and a preprogrammed EFI box, oile cooler like the  Auto Turbos got in the USA, and an 0.82 A/R on the hot side for extended high speed operation.

 

200HP in an L-Series was a factory offering!

 

Never, ever forget that!

Edited February 16, 2017 by Tony D