Turbo Gains on 1UZ-FE!

[svsgt1]

hey guys I have a question for you. i have been talking about this with several people and I get different answers so I would like to try to better understand what sort gains to expect from supercharghing or turbocharging. Here is the scenario. (All horsepower figures are at the crank)

I have a 400hp 1UZ-FE engine due to cams, ported heads, exhuast, and intake. Some people say that I will make as little as 450hp if I put an intercooled turbo system on that engine while others say it will be as high as 550hp. From what I understand the amount of power is directly related to how much air and fuel you can put into your engine. So if you have two naturally aspirated 1UZ-FE engines (4L V8), and one makes 300hp and one makes 400hp, obviously the amount of air flow between the two engines differ, or one engine is more efficient then the other, or both. So lets say that is at 0psi boost or at 14.7psi absolute pressure. (For this topic lets just use the boost pressure, which is 0psi when naturally aspirated) Lets say that the two engines mentioned have different amount of air flow. The 400hp engine has more air flow. So if we add 8psi to both engines the airflow should increase by roughly 50% in perfect unreal conditions. So if the 300hp engine flows 30 lbs/min and the 400hp engine flows 40 lbs/min with no boost, after applying 8psi the theoretical flow would be 45 lbs/min for the 300hp engine and 60 lbs/min for the 400hp engine. Each engine would gain 50% airflow and 50% power. (Yes I know this is not real. In reality there are many other variables that prevent you fom getting that full 50% gain in power.) So with that theory both engines of the same size should get the same percentage of increase in power from the same amount of boost.

This seems to make sense to me as the turbo on the more powerful engine has to actually push more air in order to achieve 8psi. So if you had a 1000hp engine and you added a turbo, that turbo would have to push a lot more air then a turbo on a 300hp engine to achieve the same psi. (That makes sense as they make different size turbos for different applications etc)

So if I turbo at 8psi my 400hp naturally aspirated engine, what sort of hp shoudl I get from it. From the math it will make a theortical increase of 50% which is not possible due to many factors. I do plan on using an intercooler so that will help with the amount of power increase. I think a realistic 30-35% would be what I would expect. That would give me roughly 520-540hp at the crank. That sounds on the high side but the Rod Millen supercharger adds 70-90 WHEEL hp at 4-6 psi, which translate to roughly 82-105 hp at the crank increase. That is about 40-50% increase on a stock 1UZFE engine. And the twin turbo LS400 on this site had a gain of 152 WHEEL hp at 8psi, which was about an 88% increase in power over a stock 1UZFE. And both these examples are not intercooled.

Granted, I would need a turbo powerful enough to give me 8psi for the flow requirements of a 400hp naturally aspirated engine, but that 8psi shoudl still yeild roughly the same percentage in power increase. And wouldn't a turbo make more power in terms of percentage on an engine that has a better intake and exhaust (ie. free flowing engine) as compared to a stock, restrictive engine. So please any advice or opinions or ideas woudl be great. Thanks!

 

[svsgt1]

My mistake, the Rod Millen supercharger is intercooled. So that 70-90 Wheel hp increase at 4-6 psi is with an intercooler. But the twin turbo on this site is NOT intercooled and made an 88% increase in power at 8psi. I just don't see how putting an intercooled turbo at 8psi on a 400hp engine will only give me 450hp. That is only a 12% increase in power.

 

[Lextreme II]

I think the best thing right now is to get a true baseline. Dyno you car and see how much the N/A put out. From the base line, we can calculate the grain.

 

[JBrady]

I think the best thing right now is to get a true baseline. Dyno you car and see how much the N/A put out. From the base line, we can calculate the grain.

This is good advice... I was about to suggest the same.

Your theory on boost vs gain is pretty good. But, boost is NOT an accurate measure of airflow... it only measures flow resistance. Mass air flow (molecular weight) is what you want to move. If you double the mass flow into the engine you have doubled its displacement. How much power is made with that displacement becomes a function of efficiency and capacity of the various support systems.

Take a stock VVti 1UZFE rated at 300hp. That engine is flowing roughly 30 pounds of mass airflow per minute at that power level. Depending on MANY factors it is possible to gain 15lb/min at a less than 7.35psi (half a bar of pressure). It is also possible to flow less than 15lb/min additional at more than 7.35psi.

The way your engine responds to say 8psi is probably most dependant on your valve timing (camshafts). Cams with too much valve overlap do not respond as well to turbocharging as cams with less overlap. On your application it may in fact work better to go back to the stock camshafts. This should enhance your low end naturally aspirated power and response. It would also make for quicker spooling of whatever turbo you add. So, with the stock cams your power may drop say 50hp (pure guess-timation) so you would drop to 35lb/min. So, in theory, turbocharged to 7.35psi you may gain 17.5lb/min giving a total of 52.5lb/min or 525hp.

Now, with high overlap cams the following often occurs... at full boost the turbo is making (in our example here) 7.35psi at say 175 degrees F... BUT... in the exhaust manifolds there is say 12psi of pressure at say 1000 degrees F... which direction do you think flow will occur during overlap (the time that both intake and exhaust valves are open)??? Yep, backwards into the intake. Now, where is the boost level taken... yep, in the intake. So, you should see that this overlap actually creates a higher boost reading WHILE the air is flowing backwards...!!! Obviously, this is not a measure of higher mass flow. So, it is entirely possible that at a measured 7.35psi of boost, with large valve overlap cams... the gain is only 10lb/min for a total of 50lb/min or 500hp.

You would really need a LOUSY turbo system to gain less than 75hp at 7psi on your engine. With the right combination of components you could also gain 200+hp at 7psi. I would think 100hp would be extremely realistic.

 

[svsgt1]

Well thanks guys for the info. The engine was dynoed already when it was built. It still has less then 200 miles on it. Attached is the dyno sheet for the engine. This is at the crank shaft and NOT at the wheels.

About the cams, (First off I know very little about cams and their specs so please excuse my ignorance.) after I got the car and engine, the engine builder told me I could do a simple cam degree timing change to get an extra 25-30hp. But I have not done that. All I have is the spec sheet for my cams with that timing change. So attached below is not the exact specs of my cams, but what I could set my cams to and get an extra 25-30hp.

Can you guys tell me anything about my cams and if they would be good for a turbo application? Would this be a good setup to begin with? I am assuming that running 8 psi would still give me a good power boost, but how much do you think these cams and engine would make?

Thanks

 

[svsgt1]

Oh also, my engine is from a 93 lexus. I heard that was one of the best years, but I have no idea of the truth of that statement. Any extra info on this year engine woudl be good. (compression ratio, what internals are forged, etc...) The engine was completely rebuilt, bottom and top and I do know that ARP bolts were used.

 

[TTGS4]

Where did you get cams for this engine? I am in search of getting some, please give me some contact info for where you purchased them.


Thanks in advance.

 

[Miles B]

Please tell us all about your engine, including price to build it to that!

 

[svsgt1]

Well those are going to be hard questioins to answer. I beleive the cams were custom ground from the original ones. I know they were not purchased and I know the engine builder had to custom make them. They are probablly made from the originals. The heads were also ported by the same engine builder. From what I was told the cams add about 50hp and the heads add about 50hp but the intake and exhaust had to be there in order to achieve those figures. Most likely all three components added about 33hp each. (I'm guessing) But after the engine was built the engine builder found a different timing that would give an extra 25-30hp (That is what the cam spec sheet above is for) I have NOT done this change yet, but maybe in the near future I will. The engine was built in New Zealand, so that is bad news for us Americans but the Australians may benefit from that. If you want pics, then go to my website www.adamstyles.com/car.htm I have pics and videos of my car as well as when we had to put the engine in.

But I don't want to digress too much more from the topic of this thread. If you want we can start a new thread and I will be happy to answer as many questions as I can.

 

[svsgt1]

What I really need to know is if my cams will allow me to add a turbo. I'm not so concerned with if it is the best cam for a turbo (probablly isn't) I just want to know if I am going to break things if I put a turbo on this engine. JBrady said that large valve overlap can make the flow go backwards, which can't be good. But will this hurt the turbo or engine or will it only make the turbo less efficient????? And will this happen with my cams?

 

[Lextreme II]

Looks like you are going to make some serious hp with 8 psi. FI UZFE is so new and lack of data. Hopefully with your project and many others, we can easily predict hp given boost and mods.

 

[JBrady]

svsgt1,

I hate to be sceptical but I see some very surprising data in those dyno sheets. I would strongly advise you to take your car to a chassis dyno and get baseline numbers. I could be wrong... but... when you first posted 400hp... I was sceptical but enthusiastically reserved and waiting for more info. From what you have posted it is hard to know just what was done to this engine. Were high compression pistons used?

Anyway, here is how I read the numbers. First off. Torque. Torque is the force generated by burning of the fuel. Peak torque occurs at peak volumetric efficiency. This is a variable dependent on engine design. Critical things are engine size, flow capacity, cam timing and compression.

A very good rule of thumb in determining efficiency is to compare peak torque to displacement in cubic inches. 4 liters is 244 cubic inches. If the engine makes MORE than 244 lb/ft peak torque... it is efficient. The stock engine is rated 260 for 1.07tq per cid.

Let us compare a few highly developed engines
2001 BMW M5 32 valve V8, 395lb/tq, 303 cid = 1.30tq/cid
2003 BMW M3 24 valve L6, 262lb/tq, 198 cid = 1.32tq/cid
2004 ACURA NSX 24 valve V6, 224lb/tq, 194cid = 1.15tq/cid
1995 Corvette ZR1 32 valve V8, 385lb/tq, 350cid = 1.14tq/cid
2004 Toyota GTS, 16 valve L4, 130lb/tq, 110cid = 1.18tq/cid

Now, lets look at your engines rating, 376lb/tq, 244cid = 1.54tq/cid.

This is too good to be true. This is 17% more efficient than the best from above, the BMW M3 engine. That engine has 11.5 to 1 compression, makes peak torque at 4900rpm (same as shown for yours) and peak power of 333hp at 7900rpm.

Gaining HP is MUCH easier than gaining torque. Cam profile can shift the torque to a higher rpm and thereby make more HP. 300tq at 4500rpm = 257hp. That same 300tq at 8000rpm = 457hp. But, to shift the torque to a higher rpm means loosing it at lower rpms. Getting an engine to flow at high rpms also takes serious support manifolding.

Now, what I would be MUCH more willing to believe is say 1.35tq/cid for a peak of 329 at around 5000rpm. Now, if you could maintain 300tq at higher RPM (not that easy) you would need 7000rpm to make 400hp.

So, I do not want to kill your spirit. Listen, a 300hp engine in your lightweight car will perform EXTREMELY well. I just suggest you get the car a baseline dyno to find out what your real power numbers are.

 

[JBrady]

Regarding your camshaft profile. 110 lobe separation is a bit narrow but since the timing is not agressive you should be OK with these cams. Keep in mind that reground camshafts have a smaller base circle and that tends to alter the geometry and increase wear. This engine should respond very well to 8psi of boost. 100+rwhp is a very reasonable guess.

If I were to take a wild guess at your current power at the wheels... I would say 250-275rwhp. Turbocharged to 8psi should make 350-400rwhp.

 

[svsgt1]

Well thanks for the reply and the info. With that info about my cams I will probably most definitely do this turbo project. An extra 100rwhp (117hp) would be nice. But below is a long explanation of my thoughts, very long but interesting.

Also thanks for the concern about what my engine puts out currently. I will hopefully get it dynoed before and after the turbo to see what the difference is. I must say that my first reaction to your idea was that the people who built my car ripped me off and they faked the dyno sheet to make me think it had 400hp. Well then I started to think. I know nobody likes to hear that their car is under powered and I don’t want to come across in a way that makes me sound like a stupid kid arguing over the specs on his Honda Civic. So I tried to remove all emotion from my thinking and look at my experiences with the car so far. Let’s look at the math. My car weighs about 2200 lbs at should have (hopefully) 400hp. That would be 5.5 lbs/hp. I drove the race version of this car (1675 lbs with a 250hp, 2L, 4 cylinder, turbo, Subaru engine) which should have 6.7 lbs/hp. I can definitely say that my car is much quicker then the race version. The day before I drove the race version I got the chance to drive a Corvette Z06, roughly 405hp at 3100lbs = 7.65 lbs/hp. The race version was faster then the Z06. Granted it wasn’t night and day difference, it was definitely faster. I also drove my brothers Viper GTS the day before I drove my car. It has some minor modifications done to it (exhaust and rear drive ratio shortened) and it runs 12.3 sec quarter miles. I could definitely tell the difference between the speed of the viper and my car, it was quite obvious to tell the truth. His exact words were “Man, this thing is scary fast.” My friend who helped me put the engine in my car has a race trans-am that runs low 12’s, high 11’s. He made the comment that my car was the fastest he has ever driven and that it could take his in a drag race. If my car was making the 250-275rwhp that you suggest (That is 294-323hp at the crank) then that would give me a ratio of 7.48-6.81 lbs/hp, which would put it in between the race version and the Z06. I would definitely have to say it is much faster then both those cars. Now I know this is all opinion and there are many other factors besides power to weight that determines speed, but this is all speculation anyway. This should give some baseline.

The other thing is that a stock 1UZ-FE makes between 250-300hp depending on year. If you say I am making 294-323hp then that seems a little on the low side doesn’t it? Since this engine is quite restrictive in terms of air flow then wouldn’t custom made long tube, equal length, race headers (4 to1) with a full 3” exhaust system that has NO cat or muffler add about 30hp. I mean, don’t some cat back systems add 20hp. So wouldn’t the whole nine yards make 30hp (Or more but I am trying to be conservative and realistic) I would have to assume that the ported heads and custom cams make another 50hp combined. (I would say it is more like 60-70 for the combination of heads and cams but then again, I am trying to be conservative here.) I also have accustom intake that sits one inch higher then the stock manifold and if I remember correctly this would give more torque then hp. (I read that somewhere that the shape of the intake manifold has a lot to do with the characteristics of an engine.) I also have a programmable ECU in the car that was tuned when it was dynoed, I would have to assume this adds some increase in power too. I would say with all of that I would be pretty close to the advertised 396.4 hp that the dyno sheet says. I may not be at that level but I would have to say I am pretty close, maybe the 375hp range. But then again that is hp and not torque. I’m assuming that my “guess-timations” in hp would be somewhat related to torque.

The other thing is that the ratings given above for torque to CID are all based on stock engines. Is it not true that all engines made today are more restrictive then what their potential is? Aren’t they made with fuel economy and emissions in mind? If you didn’t care about those items couldn’t you produce more torque and power then what a stock engine makes? The BMW M5 makes 368 ft/lbs not 394 ft/lbs (394 is the hp rating) which is a 1.21 ratio, which is still good but closer to that of the other engines listed. The M3 is still way up there. But aren’t we comparing stock engines to modified engines, and isn’t that like apples and oranges.

I know my whole explanation has come across like I’m one of those people who thinks they have the fastest and best car in the whole world regardless of what people tell them and I’m sorry for it coming out that way. I’m just trying to give the numbers and experiences with this car and try to compare it with other cars and numbers to make this whole thing make sense. I’m not saying that I definitely have 400hp and that is final. I may have something lower, but I would disagree in that it is as low as 294-323hp. I would say it is closer to the 375 range, but it maybe 400 or it may be 350. This is all speculation. It doesn’t matter who thinks what is right, it can’t until a dyno test is given but it is fun to offer different opinions on the same topic and use logic to argue the point instead of attitude and immaturity.

Once again I am not the central source for intelligence and knowledge on this subject. JBrady knows much more then me and I thank him greatly for his input on my engine and cams for a turbo application. It will be interesting to see what this think can do with a turbo. THANKS!

 

[svsgt1]

ALso, I know JBrady was doubting the torque output of my engine and all of my thoughts were based on hp. I did state that in the reply but I just wanted to make sure that nobody got upset over this comparison. I don't know much about torque and the math behind it, all I have is the experiences I have had in my car. So please lets not turn this thread into a supercars.net forum where everyone argues over stupid stuff like little immature children.

 

[Trvln Nalzmn]

Who build the engine?

 

[svsgt1]

Honestly I don't know who the engine builder is. He is located in New Zealand and he apparently has built several 1UZ-FE engines for Saker Cars. If anyone is from that area and knows of a 1UZ-FE engine builder out there then it may be him.

 

[turboandrew]

That dyno graph looks a lot like that "desktop dyno" outputs. I wonder if that's what they gave you, and what they are basing that cam timing change on. I know a lot of us are dying to see you chassis dyno that thing!

 

[svsgt1]

That is a good question. I think the cam timing degree change is based on what the builder experienced. I was told the builder "discovered" (Please don't take this word out of context) this power increase after my engine was built. He might have accidentally tried a different cam timing on another engine or maybe he used a software program to determine that. I would figure that if he used a program to discover the timing change I would have thought he would of found it sooner rather then after my engine was finished. But I don't really know. Dyno time is not cheap so if go forwrad with the turbo project I will get eth car dynoed, hopefully before and after. If someone is from the South Florida area and wants to dyno the car for me then I would be more then happy to let them use it for a little experiment.

 

[JBrady]

svsgt1,

I apreciate your mature response. You are demonstrating clear thought and reasonable discussion.

I am not saying your numbers are impossible. Maybe your engine is actually a 5.0 liter stroker? I built a VERY torquey Ford 5.0 that made 260rwtq at 2000rpm and 314rwtq at 3500rpm. That is comparable to a 5.65 liter LS1. Keep in mind that at low RPM a 2 valve engine does not give up much to a 4 valve engine. In fact, sometimes the 2 valve works better. Now, if you truely have a 4.0 liter engine making the power/torque curves quoted... I am VERY impressed. Either way, get a dyno and know what you have.

Regarding the vehicle comparison you gave, ZO6 Corvette, Saker racer and your Saker 1UZFE... here are the following power to weight numbers (of course gearing impacts performance but...)

Z06, 405hp, 3118 lbs = 7.7 lb/hp
Saker racer, 250hp, 1675 lbs = 6.7 lb/hp
Your Saker (my hp est) 323hp, 2200 lbs = 6.8 lb/hp

Now, lets add a 200 pound driver.

Z06, 405hp, 3318 lbs = 8.2 lb/hp
Saker racer, 250hp, 1875 lbs = 7.5 lb/hp
Your Saker (my hp est) 323hp, 2400 lbs = 7.4 lb/hp

Now, lets add a 200 pound passenger:

Z06, 405hp, 3518 lbs = 8.7 lb/hp
Saker racer, 250hp, 2075 lbs = 8.3 lb/hp
Your Saker (my hp est) 323hp, 2600 lbs = 8.0 lb/hp

Also, as said gears change performance, turbo engines vary in output more than NA engines, suspension stiffness affects perception of performance. All in all it is hard to say but with a driver your car has a better ratio than the other 2 and the gap between the Sakers increases with a passenger.

BTW, previously I just did a quick google for the M5 numbers, they came from a usually reliable source, Motortrend http://motortrend.com/roadtests/sedan/112_9912_bmwm5/index3.html
So, if the actual numbers are lower that just adds support to the argument. Both the M5 and M3 are highly developed engines and their peak torque, which occurs at a lower RPM than peak power, are less effected by say catalysts than peak HP. They both have amazingly well developed heads, intakes and cam profiles and the M3 has very nice factory headers. They also have variable valve timing. Dramatic peak torque increases on either engine would be impressive.