Outer Limits 4x4 Board

has anyone done this is there a reason that everyone runs turbos besides thats how they come from the factory

Superchargers were used on diesels etc years and years ago, imo the reasoning is a turbo is free power, a blower is taking power from the crank to make the boost, turbos on diesels spool almost instantly last but not least you can adjust boost levels without changing pulleys etc and that is my story haha

modern blowers produce pure grunt, mate has a 60 with a s/charged chev 6.5, adjusable boost to about 22lbs. unstoppable,unless the nut behind the steering wheel comes loose. talk to an expert. $$,$$$

Turbos aren't free energy. Otherwise all cars would have them they are a pretty significant blockage to the exhaust and intake (intake until it spools up of course). I think turbos are cheaper to make and don't need as much servicing as superchargers (belts and greasing bearings etc) so they are more popular. I prefer supercharging as it is more linear in power delivery and are easier to tune for a backyard mechanic because of it. Also i reckon they sound better

ok fair call, can you explain why they produce a more pure form of grunt to a turbo that compresses the same amount of air.?

Yes i know there always turning, but when you jump on the loud pedal from a standing start, they are not instantly pushing maximum boost/power, although there is positive pressure there.

Simply wanting to know, ive always been on the turbo side of the fence, and hence i dont know a great deal about them.

There must be a reason why most manufacturers put turbos on rather than superchargers, cost surely would have to be pretty similar.

Kitika wrote:Turbos aren't free energy. Otherwise all cars would have them they are a pretty significant blockage to the exhaust and intake (intake until it spools up of course). I think turbos are cheaper to make and don't need as much servicing as superchargers (belts and greasing bearings etc) so they are more popular. I prefer supercharging as it is more linear in power delivery and are easier to tune for a backyard mechanic because of it. Also i reckon they sound better

No not "free" as such but what would be, wasted potential energy, which is being utilized for power, torque, fuel economy rah rah rah.

How are they easier to tune on a diesel?

Once again i dont know nor am i a expert, but a turbo selected for most diesels spool at a low rpm so the intake and exhaust blockage would have little effect on the performance of the motor.

Alot of cars do have them, are getting them, the others just havn't seen the light yet

Noone will ever be right or wrong haha, a bit like holden and ford or none of them haha

td lux wrote:has anyone done this is there a reason that everyone runs turbos besides thats how they come from the factory

theres a few people on here with them.
superchargers are not easy to fit onto a motor. they are much more responsive eg you get power straight away far faster than a turbo and most importantly straight from idle. however they take a fair bit of power ti run, tho a clutch system can help. also they like large open exhausts something the police won't be to happy with so you waste a bit of power in keeping it reasonable quiet.

turbo's work well with diesels, get a lot more power with minor increase in fuel usage. they keep the exhaust quiet and make it easy for manufactures to implement emission systems (egr).
downside is lag, especially with big turbo's and low geared vechile ie the motor revs up faster than the turbo can supply the air.

1 of my mates supercharged his diesel and ran it against another mate with the same engine factory turbo diesel. Nothing in it between them speed or power wise. The main thing I was really impressed with was the amount of control the supercharger had. Can idle up steep hills. The power is smooth and always there (no lag). He hooked up a few tyre less car bodies and towed them around. When the turbo diesel tried to do it he had to rev it and get it into boost. Ended up just sitting there spinning the wheels.

The main reason is they almost always produce the wrong amount of boost.
Too much boost when you're cruising or too little boost when you need full torque.
And they suck a huge amount of crank power doing it. A 4 litre diesel with 15psi can take 15kw to run the turbocompressor. A supercharger being less efficient will take more and take it directly off the crank.

In good operating conditions a turbo can produce more boost than backpressure. Effectively cancelling out it's pumping losses. But the main kicker for turbos is they're self balancing to engine load. Engine works harder, they produce more boost. Engine is cruising, they produce less boost and don't have a parasitic drain which kills your fuel economy.

If you're worried about turbo lag, get a turbo that's better sized for your usage. Modern variable vane turbos have removed the lag problem altogether.

The only factory supercharged diesel I know of was a mazda which used a comprex (exhuast driven) supercharger. Which technically is a turbocharger. 2 stroke diesels have a blower to get them starting in the right direction, it isn't a supercharger as it doesn't compress the intake charge. They turbocharged the high output versions of those motors.

what i want to do it to is a 13bt i know it is alrady turbo but it has so much turbo lag i have talked to a lot of people about a different turbo but i can't get any one that can get me a turbo that will remove the lag between idle and 2000 revs i need more response in this area because with 35's it just has no go without the turbo i have done a few comps and when i'm winching the turbo lag is a painfull to drive with to say the least turbo already runing higher boost ect i wanted a superchager to try and fix this problem or help with it don't want diff gears can't loose any more top speed it is slow enough

you could always try twin charging it (turbo'd and supercharged at the same time)

td lux wrote:what i want to do it to is a 13bt i know it is alrady turbo but it has so much turbo lag i have talked to a lot of people about a different turbo but i can't get any one that can get me a turbo that will remove the lag between idle and 2000 revs i need more response in this area because with 35's it just has no go without the turbo i have done a few comps and when i'm winching the turbo lag is a painfull to drive with to say the least turbo already runing higher boost ect i wanted a superchager to try and fix this problem or help with it don't want diff gears can't loose any more top speed it is slow enough

Garrett GT2052.
I've mapped this turbo out for application on the Toyota 3B and over a dozen people have fitted it.
Here's a recent conversion from CT26 to GT2052:
http://forum.ih8mud.com/diesel-tech-24- ... video.html

If you want to run more than 15psi boost, the GT2056 is the next step up.

KiwiBacon wrote:The main reason is they almost always produce the wrong amount of boost.
Too much boost when you're cruising or too little boost when you need full torque.

From your posts it seems you know a swag about turbo's, but from statements like that the opposite can be said for blowers.

There is no more a predictable boost delivery given than that of a positive displacement supercharger. They don't have linear boost delivery like a turbo (be it in relation to revs or exhaust expansion, it's still linear.)

They will not boost at cruise load, thanks to bypass valves. They will give 100% boost when you want full torque, instantly, unlike a turbo.


The only part I agree on is parasitic loss, the only downside to a blower. But the benefits far outweigh the loss.


The main reason 99% of diesels are turbo'd is cost, ask anyone, like Justin from Cappa who sell a turbo kit just to be competetive. Who's going to spend $5k on a decent blower when a turbo is half, for 'similar' results....?

Turbos are traditionally used, because most diesel powered machinery operate at a set rpm, and often at a constant load. So the problem of variable air volume across a speed range is moot.

what i want to do it to is a 13bt i know it is alrady turbo but it has so much turbo lag

Sounds like you haven't been talking to the right people. There is no reason you can't get boost from about 1000rpm up with a 13bt. You might have a turbo problem, an exhaust problem, or an injector pump problem.

-Nemesis- wrote: There is no more a predictable boost delivery given than that of a positive displacement supercharger. They don't have linear boost delivery like a turbo (be it in relation to revs or exhaust expansion, it's still linear.)

They will not boost at cruise load, thanks to bypass valves. They will give 100% boost when you want full torque, instantly, unlike a turbo.

The bypass valve is the problem.
On a petrol it's easy, it's tied into the throttle body so when the throttle body is opened the supercharger bypass is closed.
Petrols being air-throttled this works very well. Also for a petrol engine there is no reason to add boost until the throttle is already open. Otherwise you're throttling boosted air which is a complete waste.

But diesels are rpm governed, the pedal position can have no relation to the fuel being injected or the boost required.
For this reason a bypass valve off the pedal isn't much use.
At cruise my diesel pulls 8-9psi boost, pedal halfway down. A supercharger would be in no-mans land. Full boost (20psi) isn't needed but with no boost EGT's would be too high.

Cost isn't the reason superchargers aren't used. Plenty of people have thrown the chequebook at diesel performance and spent far more than a supercharger install.
There are home-build supercharged diesel stories around the net. But there always seem to be more in progress than completed. One guy in NZ has one on his 5L diesel hilux, he has the supercharger on a switch and only turns it on when needed.
In the US there are several drag trucks I believe running centrifugal superchargers, but only for off-the-line kick, turbos take over.

The other point is people wanting boost from idle. Boost from idle isn't that much use.
I'm running a turbo small enough to give me 17psi boost by 1400rpm. I do have boost from idle, so why do I measure it at 1400rpm? Because that's the lowest rpm my engine can smoothly deliver that amount of torque. Below that rpm it idles happily up hills pulling 3-5psi, but asking for more torque (and boost) while holding very low revs results in a lot of torsional vibration.
If I tripled the weight of my flywheel it would probably be okay, but it's easier to simply pull 1500rpm in those situations.

i have tried 2 different turbos one was factory turbo one was gt2052 it is still not producing enough torque at low revs it needs that spool up time untill about 2000 revs it is only a 4 so it has stuff all torque without the turbo it is running 15-17 psi the pump, injectors ect have been done and tuned it will get up and boogy but that isn't the problem it is at low revs when the turbo isn't working i thought a blower could be set to run a decent amount of boost at the lower end of the rev range and hold it right through the range or am i better off changing to a lager motor i want to keep diesel it would have to be a 1hz ect they are rediculs price by the time i got one and got some power out of it and got it in it would have to be more expensive than a blower even with all the problems insalling one would create or am i wrong would it be chaper to do a bigger motor

td lux wrote:I have tried 2 different turbos, one was factory turbo, one was gt2052. It is still not producing enough torque at low revs, it needs that spool up time untill about 2000 revs.
It is only a 4, so it has stuff all torque without the turbo. It is running 15-17 psi, the pump, injectors ect have been done and tuned.
It will get up and boogy, but that isn't the problem, it is at low revs when the turbo isn't working.
I thought a blower could be set to run a decent amount of boost at the lower end of the rev range and hold it right through the range, or am i better off changing to a larger motor?
I want to keep diesel. It would have to be a 1hz ect they are ridiculous price by the time i got one and got some power out of it and got it in, it would have to be more expensive than a blower, even with all the problems insalling one would create.
Or am i wrong would it be cheaper to do a bigger motor?

fixed punctuation to make it readable, still, your wording doesnt help the cause...


what engine do you have?

KiwiBacon wrote: 2 stroke diesels have a blower to get them starting in the right direction, it isn't a supercharger as it doesn't compress the intake charge. They turbocharged the high output versions of those motors.

2 Stroke diesels use the supercharger for scavanging. The direction the engine starts in is decided by the starter motor.

They do provide positive air pressure (But not alot), the only reason these are classed as N/A is because the piston covers the air box port in the cylinder sleeve before the exhaust valves close, therefore there is only atmospheric pressure in the cylinder before compression takes place.
From memory the turbo versions of these engines use a different cam, so the exhaust valve is closed before the piston covers the air box port in the cylinder wall, allowing postive pressures to be set before compression.

td lux wrote:i have tried 2 different turbos one was factory turbo one was gt2052 it is still not producing enough torque at low revs it needs that spool up time untill about 2000 revs it is only a 4 so it has stuff all torque without the turbo it is running 15-17 psi the pump, injectors ect have been done and tuned it will get up and boogy but that isn't the problem it is at low revs when the turbo isn't working i thought a blower could be set to run a decent amount of boost at the lower end of the rev range and hold it right through the range or am i better off changing to a lager motor i want to keep diesel it would have to be a 1hz ect they are rediculs price by the time i got one and got some power out of it and got it in it would have to be more expensive than a blower even with all the problems insalling one would create or am i wrong would it be chaper to do a bigger motor

If a GT2052 won't provide boost under 2000, then you've got other issues. Does your fuel pump have an aneroid fitted? If so check it's not leaking (blow down the hose). Once you know it's not leaking, check it's working and adjusted properly.

I had a punctured aneroid diaphragm in my Isuzu, it also killed all boost below 2000 through restricting fuel. Basically it wasn't opening until 15psi boost instead of the 4 psi which it was supposed to.

I vote for a bigger motor, IMO,
It seems like you will spend sooo much more time, effort and money in trying to get the little 13bt to a level were a bigger motor like a 1HZ will start.
You could fit a small supercharger like the sc14 with the right pulley to give boost down low,but you would probably need to be able to switch it off as the turbo boost increased or it would become a blockage in the system,

I know the Haltech computor running my turbo has inputs to power something (like turning off the supercharger) when boost gets to a set point.

But I think if it was me I would be looking for bigger cubes to start with.

TD LUX just find a reputable turbo specialist and take your turbo to them, tell them what you want the turbo to do and they'll be able to modify the size and pitch of the compressor and turbine wheels within your turbo to make it react the way you want. it is just a matter of tuning the turbo so to speak, they just change the wheels to make it suit your application.