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Dramier

Factory oil cooler questions

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I picked up a 280ZX turbo engine complete to swap into my '76 280Z, and I noticed that it has an automatic flywheel on it and a gigantic oil cooler sandwitch plate where the oil filter is mounted.

 

It has the two gigantic banjo bolts, but I didn't get the oil cooler or lines because they were crushed in the original car.   My questions are pretty simple...

 

First and foremost, is it worth it to invest in an oil cooler and the appropriate AN fitting lines on a sub 300 horsepower car?   Plans for this block are just to run megasquirt, a good quality intercooler, some 400 to 500CC injectors depending on what I find, and run at most 14 pounds of boost.   I figure the setup is going to end up around the 250HP mark more than likely if I'm lucky, maybe a little more.   

 

Second question, if I do not use the oil cooler, is that adapter removable like most aftermarket ones where I just have to remove it and screw the oil filter on it its place?   

 

If it's not a simple remove and replace with oil filter, is there a proper or easy way to adapt it back to no oil cooler?   I prefer things like this to always be reversible, so I don't want to weld if at all possible blocking it up.  

 

Last thing, it's an F54 with a P90 head, and because it has an automatic flywheel I'm guessing its a pretty safe guess that it's an '81 motor.   Is there any way to narrow down the year model by looking at the engine and determine if it's a CA model or not, etc?   I've searched extensively but haven't really seen much on pinpointing by engine only as far as that goes.   

 

Going along with the above, since it was an automatic car, is there anything specific to the automatic engines that I need to address before I start the swap?   I know there are supposed to be spacers on the flywheel that have to be removed and I figure those will be self evident when I have both motors out.   I didn't see anything on the motor that looked automatic specific, but honestly I never look at automatic versions so I thought I better ask the experts.   

 

Thanks in advance and I hope to have a build thread up for the turbo swap before the summer ends.   Hope everybody is doing well and keeping their Z's on the road!

 

 

 

 

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Yes it is always a good idea to run an oil cooler on a Turbo engine. Turbo's heat the oil like crazy, even stock Turbo's at boosts under 10 lbs. You will never find a factory Turbo car without an oil cooler. Turbo's heat the bloody snot out of oil... even at low boost levels ( 5 psi ). Run an oil cooler....period.

 

Tip for engine oil. Use the best Synthetic oil you can. The best synthetics are full Ester oils, like Amsoil, Redline Motul, Joe Gibbs ( Driven oils ). They cost more but they stand up to higher oil temperatures better. The point of highest oil temperature is at the Turbo oil journal. HTSP ( high temperature shear point ) is very important in a Turbo motor. A good 10w-40 weight synthetic in the above mentioned brands will suit your engine just fine.

 

Regarding the Automatic crankshaft. I think the only other thing you have to remember is to install a pilot bushing for the transmission input shaft. Crank should already be drilled to proper size from factory.

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400-500cc injectors for stock turbo at 14psi seems excessive. You can hit 250hp on stock injectors.

 

 

Not safely.

 

You'll be really pushing stock injectors at max rate to get that.  Always better to keep the Injector Duty cycle around 80% max  if you can.  250 HP on stock injectors is going to be really pushing them. Always good to have a little extra over head. Modern injectors have much better spray patterns than old injectors.  You can get injectors these days larger than 1,000 cc's that idle just fine at 750 rpm. ( Genesis and Genesis II injectors by USRT for one example )

 

And the stock injectors are calculated to run Batch or Multi Port fired which is un-timed. If you switch to a standalone system and want to use Sequential fire, then you have to up the injector size as it is a timed system and the injectors have much less time to inject the same amount of fuel. 

 

Edit: 280ZX Turbo injectors are 265cc. You'd be pushing stock 280ZX Turbo injectors to 100% IDC at 3 bar ( 43.5 psi ) to achieve 250 hp. You need at least 330cc at 80% IDC to achieve 250HP safely.

 

Note BSFC entered as .60 which is reasonable for a Turbo car. 80% IDC. 43.5 psi ( 3 BAR ) fuel pressure = 328cc. If you calculate .65 as a BSFC ( rich safe mixture for a Turbo )  you will need 355 cc injectors to safely achieve 250HP.

 

Here's a link to a good site that allows you to accurately calculate injector sizes required for HP levels in NA, Turbo and Supercharged cars.

 

http://www.fuelinjector.citymaker.com/Fuel_Injector_Flow_Rates.html

 

Even at 4.0 BAR fuel pressure ( 58.0 psi ) the stock injectors only flow 305cc. That's not enough. Not saying that some people haven't achieved 250 hp on stock 280ZX injectors. It's just that they are really, really on the ragged edge.... just my .02c. 

Edited by Chickenman

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Yes it is always a good idea to run an oil cooler on a Turbo engine. Turbo's heat the oil like crazy, even stock Turbo's at boosts under 10 lbs. You will never find a factory Turbo car without an oil cooler. Turbo's heat the bloody snot out of oil... even at low boost levels ( 5 psi ). Run an oil cooler....period.

 

Tip for engine oil. Use the best Synthetic oil you can. The best synthetics are full Ester oils, like Amsoil, Redline Motul, Joe Gibbs ( Driven oils ). They cost more but they stand up to higher oil temperatures better. The point of highest oil temperature is at the Turbo oil journal. HTSP ( high temperature shear point ) is very important in a Turbo motor. A good 10w-40 weight synthetic in the above mentioned brands will suit your engine just fine.

 

Regarding the Automatic crankshaft. I think the only other thing you have to remember is to install a pilot bushing for the transmission input shaft. Crank should already be drilled to proper size from factory.

 

That's odd, not trying to argue but I don't recall there being an oil cooler on my '85 300ZX Turbo.   Maybe I just don't remember it but I definitely do not remember it having one.  

 

I did some searching and already found banjo to AN fittings so I'm thinking an Earl's oil cooler will fit the bill nicely.   Just have to figure out where to wedge it in the front. Thankfully the factory banjo bolts are still there!

 

Regarding oil, I was planning on running Valvoline VR oil as I've read a big discussion (possibly on here?) about it being the best for these motors.   I've used Motul many times in the past on Volkswagen and Porsche projects so I'm familiar with it but I would think synthetics would be less desirable on this motor, especially since I live in Texas and we have some brutally hot summers.   

 

Not really. You'll be really pushing stock injectors at max rate to get that. Always better to keep the Injector Duty cycle below 80% if you can.  250 HP on stock injectors is going to be pushing them. Always good to have a little extra over head. Modern injectors have much better spray patterns than old injectors.  You can get injectors these days larger than 1,000 cc's that idle just fine at 750 rpm. ( Genesis and Genesis II injectors by USRT for one example )

 

And the stock injectors are calculated to run Batch or Multi Port fired which is un-timed. If you switch to a standalone system and want to use Sequential fire, then you have to up the injector size as it is a timed system and the injectors have much less time to inject the same amount of fuel. 

 

Edit: 280ZX Turbo injectors are 265cc. You'd be pushing stock 280ZX Turbo injectors to 100% IDC at 3 bar ( 43.5 psi ) to achieve 250 hp. You need at least 330cc at 80% IDC to achieve 250HP safely.

 

Note BSFC entered as .60 which is reasonable for a Turbo car. 80% IDC. 43.5 psi fuel pressure = 328cc. If you calculate .65 as a BSFC ( rich safe mixture for a Turbo )  you will need 355 cc injectors to safely achieve 250HP. Here's a link to a good site that allows you to calculate injector sizes required for HP levels in NA, Turbo and Supercharged cars.

 

http://www.fuelinjector.citymaker.com/Fuel_Injector_Flow_Rates.html

 

Not saying that some people haven't achieved 250 hp on stock 280ZX injectors. It's just that they are really on the ragged edge.... just my .02c. 

 

I used the ratios calculator outlined in Corky Bell's "Maximum Boost" book to arrive at a minimum 400cc injector.   I actually calculated a 349cc injector when I did it but since I know that injectors are commonly available in whole number sizes I figured a 400 or 440 being a common injector would be a safe bet.   I plan on tuning to a 70% duty cycle maximum and just see where that lands and call it a day.   I figure if I'm running a 440cc injector and I'm not pushing 250HP at 70% duty cycle then I have something else seriously wrong.   Either way I'm looking more at duty cycle, timing and engine temperature as my limiting factors than specific horsepower.   If it puts down 320HP and everything else looks kosher obviously I will be okay with it.   Hopefully that comes across correctly.   

 

I've heard of people achieving mid 200 numbers on stock turbo injectors with rising rate regulators, etc, but I don't want to be on the bleeding edge when I dial everything up.   I want the engine to just barely be breathing hard.   I'd rather daily drive a car with plenty of room than be constantly worried that any second there's going to be a new hole in my block where something violently exited.  

Edited by Dramier

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 You will never find a factory Turbo car without an oil cooler.

 

In fact, the 280ZXT was sold without an oil cooler. Many of them, actually. In the US, ONLY the automatic transmission cars got them.

 

 

Not safely.

 

You can safely push 250HP on the stock injectors. I'd prefer not to, but it's been done that way for literally decades. On the stock computer, even! Is it the best route? Nope. Would I recommend it? Nope.

 

Stock turbo will stop making power at 17PSI. Stock injectors will stop making power at about 16PSI. At 14lbs, with a stock cam and head, even with the best aftermarket computer out there you'll struggle to make 250HP at the wheels-but you can make it at the crankshaft and return 28-30MPG on the highway to boot. Best I've personally done is 219RWHP at 14lbs, stock cam and head, stock injectors, with MS1-extra controlling it. Had 88% duty cycle going there. I believe, if you go through your injector calculations, you'll find they are for flywheel horsepower, which in a manual car will be approximately 18% higher, and in an automatic approximately 22% higher. (Both of those are just approximations-driveline losses vary with the car's setup, wear, fluid viscosity, etc...without an engine dyno before and a wheel dyno after, you will never really know.)

 

As to engine oils, Yes, synthetics are good. But you also need to realize you have a flat-tappet, solid lifter cam. These require oils with additive packages that have enough EP additives to maintain lubrication when the cam goes over-the-nose. Most modern synthetics DO NOT do this and so you need to take care when you're choosing an oil to get one that has an API rating of SL or prior-NOT SM or SN! SM and SN rated oils were not designed to handle flat-tappet cams and do not provide the protection needed. There's a long story behind it, dealing with catalytic converters, the EPA, rollerized valvetrains...long story and pretty boring. Suffice to say, I personally run Valvoline VR-1 Synthetic, and for break-in oils I use 4T motorcycle oils...many bikes still run solid flat-tappet cams, and so they still have a good EP additive package for now.

Edited by Xnke

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I'm quite familiar with the ZDDP issue, and it is certainly true that you must be aware of this issue these days. .

 

All the oils I recommended have adequate amounts of ZDDP . Note I did not recommend any " off the shelf " synthetic oils such Mobile 1, or Castrol . Energy Star rated oils in the thinner weights ( less than a 10w-30 ) are the prime candidates for ZDDP reduction. " Most 10w-40 "  oils are not Energy Star rated and contain higher levels of ZDDP. The three oil brands  I recommended are have more than adequate protection. Many manufacturers such as Redline, Amsoil, and Joe Gibbs makes niche market oils that are specifically formulated for Flat Tappet High performance engines and include  more than adequate amounts of ZDDP.

 

Rotella T6 full synthetic is also a very, very good oil in Turbo cars. It's an HDEO ( Heavy Duty Engine Oil ) recommended for Diesels but can be used in most Gasoline engines. Rated very highly on Turbo forums, Bike forums, Diesel forums and oil analysis readings always come out very good. Unfortunately it is only available in a 5w-40 ( for the FULL synthetic ) and I feel that the cold weight is a bit thin for the bearing clearances on an older design motor.

 

I'm a firn believer in high quality Synthetic oils. Been that way since the 1980's and it's repaid me many times over. My DD Audi A4 has had a steady diet of either Amsoil or Rotella T6 synthetics since the day I owned it ( 126,00 KM ). Previous owner also used Synthetics. ( Mobile 1... not my favorite choice for various reasons... but decent stuff ). Car now has 253,000 KM on it. Has been chipped and boosting 15 to 18 lbs daily. Still has the factory BW  K03 Turbo on it with zero shaft play and compression is 180 PSI across the board. Gotta be happy with that!! 

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Regarding oil, I was planning on running Valvoline VR oil as I've read a big discussion (possibly on here?) about it being the best for these motors.   I've used Motul many times in the past on Volkswagen and Porsche projects so I'm familiar with it but I would think synthetics would be less desirable on this motor, especially since I live in Texas and we have some brutally hot summers. 

Valvoline VR is a very good Dino oil. Fine for a NA engine.  But personally, I would never run a Dino oil in a Turbo car, especially a high boost Turbo car. Synthetics can withstand the high oil temps found at the Turbo journals much better than Dino oils. Thta is where your paek oil temps are. Not the temps measured in the oil pan. But the temps at the Turbo journals.

 

Speaking of heat. Why wouldn't you run a Synthetic oil in Texas?  Synthetic oils excel in high temperature conditions. They are far superior to any Dino oils in that aspect. Naturally you have to choose the correct viscosity for the conditions you run and the modifications made to the engine. And buy a a high quality Synthetic.

 

Some of the " off the shelf " brands sold in North America can't even be sold as Synthetics in Europe and Asia. USA big oil companies convinced Congress to " Relax " the Synthetic standards back in the 1990;s so they could manufacture " Synthetic "  products cheaper.  Long story, but you can look it up at BobIsTheOilGuy. Juts my .02c. beer_yum.gif

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That's odd, not trying to argue but I don't recall there being an oil cooler on my '85 300ZX Turbo.   Maybe I just don't remember it but I definitely do not remember it having one.

1985 300ZX Turbo Auto transmission cars come equipped with an Air to Oil cooler....

 

Again this is the odd situation of Nissan not using an engine oil cooler on the manual transmission models but not the Auto transmission models. I have no idea why they would have done that. Very strange. Engine oil temps can get just as high on a Manual tranny car as an Auto. So why would Nissan choose to not put one on the Manual transmission models. Doesn't make sound engineering sense.

 

Edit: Having a think about this and I just realized why the Auto tranny cars came with an external engine oil cooler and the NA cars did not. . The Thermal load of the hot transmission fluid running through the radiator likely cause cooling issues with water temp and/or oil temps. Thermal " run away " is the term I believe. So the engineers were forced to add an external oil cooler as cooling package was borderline with the Automatic cars. The extra Thermal load of the Auto tranny just put things over the edge for daily commutes.

 

Many European cars use water to oil engine coolers instead of Air to oil engine coolers. Even NA engines. A lot of them also come equipped with Factory engine oil temperature gauges. High speed Autobahn running makes an oil temp gauge almost a necessity. Run a oil temp gauge on a Track car that does not have an oil cooler and I think you'll be shocked at the oil temps you see.

 

Bottom line.... we all know that Turbo cars build higher engine oil temps than the NA versions. That's a fact. . An external oil temp cooler ( with a temp modulated plate ) is just common sense. Especially on modded cars. Not arguing either and it's just my .02c. Take it for what it's worth.  Cheers..

Edited by Chickenman

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Valvoline VR is a very good Dino oil. Fine for a NA engine.  But personally, I would never run a Dino oil in a Turbo car, especially a high boost Turbo car. Synthetics can withstand the high oil temps found at the Turbo journals much better than Dino oils. Thta is where your paek oil temps are. Not the temps measured in the oil pan. But the temps at the Turbo journals.

 

Speaking of heat. Why wouldn't you run a Synthetic oil in Texas?  Synthetic oils excel in high temperature conditions. They are far superior to any Dino oils in that aspect. Naturally you have to choose the correct viscosity for the conditions you run and the modifications made to the engine. And buy a a high quality Synthetic.

 

Some of the " off the shelf " brands sold in North America can't even be sold as Synthetics in Europe and Asia. USA big oil companies convinced Congress to " Relax " the Synthetic standards back in the 1990;s so they could manufacture " Synthetic "  products cheaper.  Long story, but you can look it up at BobIsTheOilGuy. Juts my .02c. beer_yum.gif

 

I think I need to go back and re-learn what I 'remember' about synthetics because everything I've seen mentioned so far seems to indicate I'm either not remembering things or I picked up some bad information somewhere along the way.   

 

Thanks for your input and helping me wade through this.   I've decided to go to an Earl's oil cooler and figure out a good place to mount it.   Might screw with the intercooler ducting a bit, but I should be able to figure something out.    That explains to me why I keep seeing restored Z's with the oil cooler oddly positioned way out front of the lower valance area.   Probably didn't have much room for it in the stock location.  

 

Now I've got to go do some re-education on oils.   :)

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Dramier: BobIsTheOilGuy is an excellent resource for technical information on lubricants. Intelligent discussions, lab analysis and active/retired Petro-Chemical engineers frequent the site. Well worth adding to favorites:

 

https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=cfrm

 

Yes, the oil coolers sticking exposed out front are just a " Fan Boy " trend. Tons of space in the nose for an oil cooler on a Z.

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Juts a few of tips on the oil cooler mounting. Earl's may cover this in their FAQ

 

1: Do not mount the oil cooler falt against the Rad or AC condenser. Space it away by a minimum of 1" . Flush mounting reduces air flow considerably. Same with Auto Trans coolers or PS coolers. Those through the Rad zip ties that come in some kits are a quick, but inefficinet means of mounting. You need some gap for proper airflow. Lots of room in the Z nose to make a proper mounting bracket.

 

2: When running the hoses, avoid using turns as much as possible. Every time you add an angled fitting you cause a fluid restriction. It can all add up. If you must use an angle for clearance, try and avoid using an Angled adapter fitting. These can be very restrictive. Use a bent tube fitting on the end of the hose instead. These flow much better than the cast adapters. If you must use a bent Tube, try the minimum angle possible;e. A 30 degree or 45 degree bent Tube is prferred over a 90 degree. The sharper the turn the more the restriction. Ideally, if you can use all straight adapters and hose end fittings that is best.

 

3: Do run a thermostatic sandwich plate if ambient temps get on the cool side. Lots of good suppliers, but Mocal is a good brand. So is Canton, Eral's Setrab etc:

 

Lots of places to buy them, but this gives you an idea of what is available:

 

http://www.racerpartswholesale.com/category/Mocal_Sandwich_Plate

 

http://www.racerpartswholesale.com/product/13462/Mocal_Sandwich_Plate

Edited by Chickenman

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1: Do not mount the oil cooler falt against the Rad or AC condenser. Space it away by a minimum of 1" . Flush mounting reduces air flow considerably. Same with Auto Trans coolers or PS coolers. Those through the Rad zip ties that come in some kits are a quick, but inefficinet means of mounting. You need some gap for proper airflow. Lots of room in the Z nose to make a proper mounting bracket.

 

 

 

Thats not what these guys say

 

http://www.mocal.co.uk/FAQ.html

 

But mine is mounted how you describe and its fine.  All components where mounted via factory holes that my car isn't using anymore. Very basic aluminum brackets.  Works extremely well. Never seen oil temps above 190 yet.

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Edited by Timecode

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That's very interesting. Contrary to what I've read in several cooling articles in reputable articles in Race Car engineering, Circle Track racing and other Technical books. Those recommendations apply to racing cars though, where heat management is critical. Carroll Smith recommends to avoid mounting any auxilary cooler in front of the water radiator. That's relatively easy to design  in a Race car, but  not always practical in a passenger car. 

 

Nice installation of the Setrab. I like how you've used rubber mounts to isolate the oil cooler from vibration. A critical point often over looked. 

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Some companies recommend different locations for their coolers. Mine is an 1"-2" in front of the rad. I can't get temps over 190 no matter how hard I try. I saw no increase in my water temp by adding the oil cooler so the location works, at least on our cars.

On a side note, I was experiencing oil pressure drop on tight corners. I was going to get an accusump but thought that the cooler oil will let the oil maintain its viscosity and it did. Now there is almost no pressure drop.

Edited by Timecode

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I used to Hillclimb and the heat from that beat the snot out of the oil and cause viscosity loss in some oils.  

 

Some of the " off the shelf " synthetics lose a lot of viscosity under heat. Mobile 1 ( new formulation ) and Castrol Synthetics seem to be the worst. Amsoil products are affected very little by heat. Used to pull a trailer loaded with all my Tires and extra gear up the Coquihalla . Long, long steep high speed mountain climb ( See Discovery Channels " Highway Thru Hell ) . Mobile 1 10w-30 would lose 10 psi by the top of the pull. Would slowly recovery when we got to the flats. Amsoil 10w-30 under same conditions lost only 2 psi. All of the true esters like Amsoil, Redline, Motul and Joe Gibbs seem to retain viscosity under extreme heat loads very well.

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