Thread: Eliminate turbo lag

Originally Posted by PAT303

One advantage of the water cooler is that you can mount a small rad and fan,you can get them from truck wreckers,anywere as the fan forces air through not forward motion.I was looking at mounting it in the hollow inbetween the inner and outer front guard with the inlet were the blanked hole is for the LHD air vent inlet is.It would be a good thing as the air even at idle would be cooled. Pat

Pat,

I really don't think you would get anywhere near enough air flow doing that. A fan will not move more that a small percentage of the air that you would get by driving along with a direct flow of air over the radiators core.

Electric fans aren't great in terms of air flow anyway.

I have hours of datalogging from setting up chargecoolers somewhere... with static 'in traffic' running, through to 150+mph running 20psi boost, and also rolling road sessions with an absoloutely vast fan trying to cool the car down.

You need a huge airflow to cool down the inlet charge, especially if you are working the car hard.

I ended up setting my race car up with a chargecooler and radiator for it specifically, and after about a week of mucking about binned the radiator and fitted one that was over twice the size and the full width of the front opening. (about a metre) This was not obstructed by anything and had a pair of Kenlow fans on the main custom rad behind it pulling air through.

That was good enough, but you could still see the inlet charge temp rising on the data logging traces throughout a race.

On another note about running rads out of the line of direct airflow, I used to co drive in competitive safaris / hill rallies in a 4.8litre 100" Defender which ran about 360bhp and a rear mount rad with a vast scoop above the cab, and that was a real pain at times so direct airflow is very important.

I will see if I can find the data logging info I have regarding charge cooling.

I also have flow figures and so on from getting everything flow tested and it was very interesting and succesful, but... and this is a big but.... It cost a fortune....

Nothing was standard and we were looking at huge improvements... 210bhp to 391bhp and 365lb/ft of torque. You wont get this from a TDI. It is in my opinion a bit of a waste of time. Without mapable electronic control of the fueling you are going to struggle. (Those figures werent just improved by chargecooling.... we had gas flowing, Motec management, custoem pistons, cams, huge custom roller bearing turbo, 3" exhaust and tubular manifold etc etc.

Even after all this work... we still had a car that was really compromised... I cant remeber the exact figures from the last power run but it was something like.

2000rpm 60bhp!
3000rpm 90bhp!
4000rpm 300bhp
5000rpm 370bhp
6000rpm 391bhp

It jumped by over 200bhp in the space of 1000 rpm. It would bite you very hard if you werent careful.

There are other issues too.... Does it have a water heated inlet manifold... if so you could to disable it, which then makes it a bugger to run cold and so on.. (dont know if a TDI has this)

Good luck if you do try it though!

I think a decent modern turbo (things have moved on alot) and manifold would be the best place to start.

anyway I have waffeled a bit so I will shut up!!

Edited to add this picture... What looks like the huge radiator on the front... was just for the chargecooler...!



Cheers
Pete

I,like most other people I think look at my truck and think "I wonder about this''and get idea's but I agree that alot of the performance parts etc were really making up for technology that wasn't around then but is now.VVT's are one of the things that have come out of late that have ''fixed'' the turbo's biggest problem of off idle lag.I don't want to re-invent the wheel but would like to try new things and a VVT is high on the list. Pat

Originally Posted by Psimpson7

Pat,

I really don't think you would get anywhere near enough air flow doing that. A fan will not move more that a small percentage of the air that you would get by driving along with a direct flow of air over the radiators core.

Electric fans aren't great in terms of air flow anyway.

I have hours of datalogging from setting up chargecoolers somewhere... with static 'in traffic' running, through to 150+mph running 20psi boost, and also rolling road sessions with an absoloutely vast fan trying to cool the car down.

You need a huge airflow to cool down the inlet charge, especially if you are working the car hard.

I ended up setting my race car up with a chargecooler and radiator for it specifically, and after about a week of mucking about binned the radiator and fitted one that was over twice the size and the full width of the front opening. (about a metre) This was not obstructed by anything and had a pair of Kenlow fans on the main custom rad behind it pulling air through.

That was good enough, but you could still see the inlet charge temp rising on the data logging traces throughout a race.

On another note about running rads out of the line of direct airflow, I used to co drive in competitive safaris / hill rallies in a 4.8litre 100" Defender which ran about 360bhp and a rear mount rad with a vast scoop above the cab, and that was a real pain at times so direct airflow is very important.

I will see if I can find the data logging info I have regarding charge cooling.

I also have flow figures and so on from getting everything flow tested and it was very interesting and succesful, but... and this is a big but.... It cost a fortune....

Nothing was standard and we were looking at huge improvements... 210bhp to 391bhp and 365lb/ft of torque. You wont get this from a TDI. It is in my opinion a bit of a waste of time. Without mapable electronic control of the fueling you are going to struggle. (Those figures werent just improved by chargecooling.... we had gas flowing, Motec management, custoem pistons, cams, huge custom roller bearing turbo, 3" exhaust and tubular manifold etc etc.
Even after all this work... we still had a car that was really compromised... I cant remeber the exact figures from the last power run but it was something like.

2000rpm 60bhp!
3000rpm 90bhp!
4000rpm 300bhp
5000rpm 370bhp
6000rpm 391bhp

It jumped by over 200bhp in the space of 1000 rpm. It would bite you very hard if you werent careful.

There are other issues too.... Does it have a water heated inlet manifold... if so you could to disable it, which then makes it a bugger to run cold and so on.. (dont know if a TDI has this)

Good luck if you do try it though!

I think a decent modern turbo (things have moved on alot) and manifold would be the best place to start.

anyway I have waffeled a bit so I will shut up!!

Edited to add this picture... What looks like the huge radiator on the front... was just for the chargecooler...!



Cheers
Pete

Were talking about a 2.5ltr Diesel turbo here not a highpo petrol 4 banger that is built for those sort of numbers.

Fueling is a lot more simple (in some ways) with a mechanical diesel injection system than an electronic fuel injection system and you can get extremely good results just by making a few simple adjustments without needing data logging and all that stuff you need for that competition edge over the next guy.

As far as the water to air intercooler goes, the aim is more just to get it more efficient than the standard air to air intercooler rather than creat huge numbers on the data logger.

Love the lancia though, I painted one for one of my maths teachers at TAFE when I was 17 that he used to race, A beta I think it was 2l twin cam turbo that had wicked lag that was like driving a nice little pulsar or something until about 2500 and then it would leave your head back where the boost cut in.

I have no idea on numbers that it was putting out just that it was damn dangerous to drive on the road.

Hi McRover,

The problem I see is that after a point everything ends up giving diminshing returns.

Upping the fuel, and a bigger intercooler are all sensible and realistic upgrades on a reasonalble budget.

Next you could look at a custom exhaust manifold, maybe equal length primaries, and a VVT turbo.

This though is going to take you to 95% of all you could ever hope to get out of a TDI (I am not knocking TDI's here either - dont get me wrong)

You end up getting 70% of the possible increases for 30% of the cost, but the next 30% takes 70% of the cost.

Once you get past this point I really think you end up making an engine that needs constant tweaking. ( I am sure about 10years ago there was a tdi Defender built in the UK which ran to over 200bhp but it had to be rebuilt every 20000 miles)

The principles and theory can be applied to high power petrol engines or torquey diesels too....

The data logger didnt give the power figures... it recorded all the temperatures and outputs of the sensors and was incredibly useful when monitoring the inlet charge temperatures (both pre and post charge cooler and when just using the original intercooler in an earlier development stage)


Cheers
Pete

Originally Posted by JamesB

Has anybody ever considered fitting a small supercharger to a TDi to overcome the low rpm lack of power ? Mabye a jap import supercharger like the one off a toyota MR2 with the electric clutch on the front so it could turn off when the turbo reaches enough boost thus giving supercharger boost down low and turbocharger boost up high. Am unsure how one would go about plumbing etc. and how each charger would merge and affect each other. What do you people think ?

In no way am I an expert in automotive induction bla bla bla, but you are talking about a TDI landrover. From my experiance driving some wierd machinery I reckon you are better off with a variable vane turbo of some type, have the fuel pump profesionally tweaked to suit, and most importantly have someone build you a really nice tricked auto to run behind it. Failing this get a genuine AC Cobra they didnt have turbo's or turbo lag just a shocking record for killing its owners.

Justin

an easy way to improve the efficiency of the OE intercooler is to use a water tank, a small pump and a fogger or small nozzles spraying over the front of the air to air I/C and have it setup to either trigger at a set charge temp or when at full throttle.
Autospeed had a small electronic kit you could copy to make an electronic trigger for the spray.

A properly set up water/air I/C can reduce lag just by shortening the inlet tract over an air to air version.

Rick,

The length of the after turbo inlet tract doesnt seem to make much difference.

As you say with a chargecooler it can be very short, but the WRC mitshubishi lancers inlet tract seems to be about 200metres long!, and with their budgets I am pretty sure that they would have thought it through!

Agree about the water spray on to the intercooler face though... that is a good idea.

Pete

Originally Posted by Psimpson7

Hi McRover,

The problem I see is that after a point everything ends up giving diminshing returns.

Upping the fuel, and a bigger intercooler are all sensible and realistic upgrades on a reasonalble budget.

Next you could look at a custom exhaust manifold, maybe equal length primaries, and a VVT turbo.

This though is going to take you to 95% of all you could ever hope to get out of a TDI (I am not knocking TDI's here either - dont get me wrong)

You end up getting 70% of the possible increases for 30% of the cost, but the next 30% takes 70% of the cost.

Once you get past this point I really think you end up making an engine that needs constant tweaking. ( I am sure about 10years ago there was a tdi Defender built in the UK which ran to over 200bhp but it had to be rebuilt every 20000 miles)

The principles and theory can be applied to high power petrol engines or torquey diesels too....

The data logger didnt give the power figures... it recorded all the temperatures and outputs of the sensors and was incredibly useful when monitoring the inlet charge temperatures (both pre and post charge cooler and when just using the original intercooler in an earlier development stage)


Cheers
Pete

Pete,

Agree about the deminishing returns, Pereto's 80:20 rule applies. Please excuse my ignorance but can you explain what you mean by equal length primaries? does this apply to a turbo diesels? Also a custom exhaust manifold? Are we talking something cast or something made from tube? I just have some concern about the noise and heat that you get with thin walled tubed extractors. When I was a younger tacker I had a mini and I put extractors on, the noise was noticeable, even induction noise i.e. the noise of the air getting sucked into the carb.