Let Me Know What You Think: 2UZ-FE With Mods?

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MTHawkins

New Member
Messages
7
Location
UK - England
Hi,

I am new to the forum, so first of all hello !!

Ok, so this is what I am looking at doing (the engine is to be fitted in a custom space frame chassis not in a car):

2UZ-FE 4.7L ENGINE,
FITTED WITH EATON M112 SUPERCHARGER,
ALSO FITTED WITH SINGLE LARGE TURBO,
FORGED INTERNALS.

What sort of figures can I expect from the engine? not sure on the size of the turbo, looking for help on this. May consider going for the 5.4L TTC stroker kit too.

I have lots of space to fit everything so please let me know what you think, spec suggestions would be nice if you dont think this is a nice setup.

Thanks :)
 

Lextreme II

Just call me "Lex"
Messages
12,044
Location
City of Halos
If you want tons of power, you dont need stroker. Dual Chargers will give you more torque and hp than u can never imagine. Why would you need to stroke the engine? Save the stroker and get good internals and good tuning.
 

MTHawkins

New Member
Messages
7
Location
UK - England
If you want tons of power, you dont need stroker. Dual Chargers will give you more torque and hp than u can never imagine. Why would you need to stroke the engine? Save the stroker and get good internals and good tuning.

What sort of power do you think the engine will put out? With supercharger and turbo what specs would you suggest?
 

stevechumo

Active Member
Messages
3,054
Location
OC, City of Sunshine
The M112 will net you somewhere 400 rwhp easily. If you put on a turbo, then you can expect another 400 rwhp or more. If you're not looking for that kind of power, then going with either one will be perfect. However, keep in mind that if you don't have a proper intake manifold that doesn't restrict the turbo flow, you'll end up losing power. The turbo air pressure shouldn't go through the supercharger at all, if you want each charger to be efficient.
 

MTHawkins

New Member
Messages
7
Location
UK - England
The M112 will net you somewhere 400 rwhp easily. If you put on a turbo, then you can expect another 400 rwhp or more. If you're not looking for that kind of power, then going with either one will be perfect. However, keep in mind that if you don't have a proper intake manifold that doesn't restrict the turbo flow, you'll end up losing power. The turbo air pressure shouldn't go through the supercharger at all, if you want each charger to be efficient.

Thanks for the reply. You say the turbo air pressure should not go through the supercharger?

I spoke to an engine builder here in the UK and he suggested the opposite? saying that the air flowing from the turbo into the supercharger would be more dense ie: oxygen rich, and would increase the effiency. Waht do you suggest?
 

stevechumo

Active Member
Messages
3,054
Location
OC, City of Sunshine
You're very welcome. When the supercharger sucks in the air from outside (no turbo) and if the air is cold, then the O2 will be more densed than it sucks from the turbo air. Here's why. The air after the turbo is very hot, part of it is due to the exhaust heat, and part of it is because it's compressed, and that heat breaks down the O2 atoms. And when the supercharger sucks in this hot air, it'll have to compress again, thus it'll make it hotter. Compressed air will generate heat, so that's why root supercharger also needs an intercooler.

On the other hand, if the supercharger sucks in the free air from the cold environment outside, the air will be compressed only once.

The next part is air flow restriction. Let's assume the turbo pushes 15 psi of air, while the supercharger only creates 10 psi of air, then where does that remaining 5 psi of boost go? That 5 psi of boost will be pushed back to the turbo, slow down the turbo boost, because only a part of it can make through the supercharger. An example would be if the supercharger doesn't move, it's very hard to blow through it.

Justen on this forum had already tried this setup with the turbo before the supercharger, and he had to take out the supercharger because of a big loss in power, while this whole system makes more psi than the turbo setup itself. Both of his systems are very awesome by the way.

If you can have 2 throttle bodies, 1 for each charger, then it'll be a wonderful setup. But I can see it'll be very hard to control both precisely.

If the hi-performance builder that you talked to had already done this with positive result when he compares between the single charger or a twin charger, without guessing, then he may have a trick that some of us would be happy to learn about. :D
 

cribbj

"Supra" Moderator
Staff member
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4,794
Location
Houston, TX
MTHawkins, suggest you do a search here on Lextreme using terms like "twincharge" or "compound boost", etc. It's been discussed in some detail in the past.

Not to step on anyone's toes, but this is a pretty complex subject, and in fairness to everyone, you should study it thoroughly, and become familiar with the pro's & con's before taking a decision whether you want to go forward or not.
 

MTHawkins

New Member
Messages
7
Location
UK - England
id stick with the 4.7 and m112, this will see more than enough HP and torque for pretty much any purpose :D

For most purposes yes, but not for what I have in mind :cool: I want some thing real special, I chose this engine because it has tremendous tuning potential, the weight of the engine is going to be a major factor .... I will let you know more when my idea comes to fruition :D
 
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stevechumo

Active Member
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3,054
Location
OC, City of Sunshine
For most purposes yes, but not for what I have in mind :cool: I want some thing real special, I chose this engine because it has tremendous tuning potential, the weight of the engine is going to be a major factor .... I will let you know more when my idea comes to fruition :D
If you want something special, then put a quad turbo system on it if you have room. That's what I've been wanting to do for centuries. :D
 

Chicken Wing

New Member
Messages
46
Location
Sydney, Australia
Hey guys, ive looked at compund boost setups for quite some time now and I thought i should explain some of the physics to you.

The supercharger will not become a restriction in the setup, its quite a dynamic piece of machinery so it wont necessarily block air, and if it were, this means you just get positive pressure on the supercharger intake...which is good!

most roots superchargers compress the air internally, hence the heating of air and such, but there is no maximum to how much compression can be done. i.e. if you have 5 psi on the intake of the supercharger, it would take the more dense compressed air and further compress it, if you had 120psi on the intake it would still compress it further (that would be mighty warm) but lets be realistic;
say, you had the supercharger set to 6 psi and the turbos set to 9-10 psi, the compounded boost will be closer to 20 psi. now the only thing here is striking a balance as everytime you compress air it is a process where you are forcing the air particles to a smaller area they must lose some of their energy as heat. this follows a basic ideal gas law (P1V1)/T1 = (P2V2)/T2, where the P1 is the pressure at the intake, V1 is the volume of air we are analysing and T1 is the original temperature (K), so when we increase the pressure by compression, P2 increases, V2 decreases, and because the equations must equal each other T2 must rise. but remember, its always the case where, the higher the boost, the higher the heat, theres no free lunch! it just means you have to keep both the turbos and the sc within their efficiency range. if you can do that, a simple intercooler after the sc can manage the rest.

so, where, turbos tend to be more efficient than a roots supercharger it seems logical to allow the turbos to make more boost than the supercharger. this is correct and the best way to maintain intake temps.
now onto the previous point on the supercharger being a restriction, think of it like this, you are asking the supercharger to create boost right? which means if still must be pumping more air than the engine can consume, the only difference is that you are asking the supercharger to make less boost by itself. this means you can spin the charger slowly. of course, ideally you would not want a charger at all beacause psi for psi, it will be less efficient. but that defeats the purpose, and youll find a far nicer 'area under the curve' by utilising a compound boost setup.

as for exhaust restriction, for your turbos you must choose a much larger ex. housing than you would ever intend to on a turbo only car. in fact you can get away with a much larger, but remember where you want the bulk of your power to be. it is important to mention that you will need an exhaust housing much larger than normal in a twincharged setup, where the trade-off in lag is absorbed by you having a supercharger. this also means you cand make decent boost with the turbo and still remain efficient.

remember this setup works, and volkswagon do make a twinchaged 1.4 golf which makes 200bhp from factory. the best way to describe the results is, its like turbocharging a much larger displacement engine, you get the low end power, still with a decent top end from the turbos.

attached is an approximate chart of using turbos with a roots based supercharger.
remember benefits can be made with using a newer twin screw design but you have to be careful with how fast you spin it as they tend to be more efficient and its a pretty good way to make too much boost.
 

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stevechumo

Active Member
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OC, City of Sunshine
Your explanation is very interesting and it seems it's based on a very good theory. From what I see, the efficiency may be had at low boost for low-mild power engine when the restriction doesn't come into a factor much. But after a certain point of boost, the compound setup will be inefficient when the turbo is pushing more than what the supercharger can digest and cause a restriction, unless the supercharger's internal is big enough to digest all the pressure from the turbo.

The supercharger also has a limitation of boost because the more boost it has, the uneven air distribution will be greater. Some cylinders will get more air than the others, even though the supercharger manifold will be filled with air. We don't want that with high boost application.
 

cribbj

"Supra" Moderator
Staff member
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4,794
Location
Houston, TX
Chickenwing, I think you've explained the general concept pretty well, but a couple of your statements need some refining. First, let me say I'm not an authority on this subject, and frankly, I don't know that anyone currently in our forum is either.

Anyone contemplating twincharging (compound or multistage compression) should do as much research as possible on the subject, to where you're comfortable with the concept, and the physics. As usual, there's a lot of hype out on the Internet about this subject, but the real truths can be found from talking with engineers who know how to size and design multistage air compressors.

A Roots blower by definition has no internal compression. It's the restriction downstream (the engine) that creates the "boost". Of the PD machines, only the twinscrew has internal compression. But that's immaterial, because "any" time you vary the pressure or volume of air with a compressor, blower, turbo, or turboexpander (the opposite of a turbo), you're going to heat or cool it.

The Roots blower, by design, isn't suitable for high pressure ratios because again, it's not really a compressor, it's a blower. That's why it's not used in high boost applications. The other type of PD charger, the twinscrew is suitable for high pressure ratios (you see lots of twinscrew air compressors out in industry).

The equation of (P1V1)/T1 = (P2V2)/T2 is not actually the Ideal Gas Law. It's the Combined Gas Law, so called because it combines Boyle's, Charles', and a French guy with hyphenated name, who I can't remember, three laws. Most of us here probably don't care whether it's the Ideal or the Combined, but if you're going to quote it, then it probably ought to be correct.

Anytime you put two stages of compression in series, for compounding you have the possibility that one will overpower the other, so you have to run the numbers with their capacities to ensure it doesn't happen. Of particular importance (IMO) is to control the interstage pressure ratios to ensure they stay within the "happy" band of the technology you're using, and the temps stay under control. (You don't want to let your turbo get into surge, or you'll wreck it, neither do you want to be trying to create 3 bar of boost to the engine with a Roots blower, because its discharge temps will be way too high.)

Haven't looked closely at your table, but it's pretty easy to figure basic compound compression, if you assume no losses and no heating :) (which is not a real world situation) You just take each stage's pressure ratio and multiply them together. Note that the pressure ratios are MULTIPLIED, not ADDED. For example if your boost in the first stage (turbo) is 10psi, the pressure ratio of this stage would be (10+14.7)/14.7 = 1.68, and if your boost from the 2nd stage (supercharger) is 5psi, the pressure ratio of this stage would be (5+14.7)/14.7 = 1.34. The combined pressure ratio would then be 1.68*1.34 = 2.25, and converted to "boost", it would be 2.25 = (x+14.7)/14.7 ; solving for x would give you 18 psi of boost.
 
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Chicken Wing

New Member
Messages
46
Location
Sydney, Australia
Gay-Lussac is the guy your thinking of, and to go even further we never get to deal with an ideal gas within our situations (well, never really). PV=nRT if you guys are really interested.
mm yeah got me on the roots blower, wasnt thinking straight there, but for all intensive purposes the concept remains similar. which begs the question, if there is no pressure change across the lobes of the supercharger why do they generate heat?

I think youll find the 'happy band' is quite large, with most turbos cabable of creating a nice wide range of boost, and when it comes to comprsser surge or stall, a well designed comp. housing does wonders. but would we really need it? it seems at all stages the roots blower will be trying to create a lower pressure region behind it, which is more than i can say for any engine without a blower. and even then we do use blow off valves to vent the excess. and to stop crazy amounts of boost from the blower...bigger pulley.

as for the chart i cant take credit, (its a ford forum thing i found a couple of months back), but this concept is not new to them, 1000hp by 4500 rpm on the gt40 in question.
http://www.svtperformance.com/forum...pound-boost-1359whp-1219wtq-ttsc-ford-gt.html

i dont know of any way to account for heating and losses remembering this is both adiabatic AND diathermic, the diathermic being the most obviously difficult of the two. im happy with what i can get, i know the ideal gas doesnt exist and the carnot cycle is a postulate. but they're the ringleaders of my calculations and unless you know a better way...
 

cribbj

"Supra" Moderator
Staff member
Messages
4,794
Location
Houston, TX
I made a compound boost spreadsheet awhile back for my 2JZ-GZTE project, and have attached it, if anyone wants to have a play to see the kind of trouble you can get into with compound boosting. Mine is arranged according to engine RPM, so you can see the effects of changing boost at different points of the engine curve. There's a graph page, so you can see the boost curve you're generating.

It's locked, so the blue cells are the only area that can be modified, but if you want to unlock it, the PW is the same as my username.

This doesn't take into account any losses, heating, etc. - it's only the straight compound boost calc.

The surge situation I was referring to earlier, is being sure to keep the turbo compressor away from its surge line, under conditions of high pressure ratio, and relatively low flow. The sort of conditions you could easily find yourself in, in a twincharge setup, if the SC isn't keeping up with the turbo........
 

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