Upgrading The Original Turbo

[Guest Kidmans]

you dont have a spare turbo outlet pipe do you? The one attached to the red samco?

 

 

Nope sorry i dont. My 'spare' went with an engine i sold recently. No reason why you cannot use a silicone joiner and ally pipe which i feel would be better. I had to use a different section of pipe hence the red silicone hose, because my compressor outlet was slightly longer and the ally outlet woduld not bolt up properly.

[pablo 0]

thats what I have at the minute but its all a bit messy just. space with the servo is a blooming nightmare down there and any contact gives vibration through the cabin

[danpug 1]

Does anybody have a good spare turbo/manifold they want to sell? If so pm me!

[Guest Kidmans]

thats what I have at the minute but its all a bit messy just. space with the servo is a blooming nightmare down there and any contact gives vibration through the cabin

 

 

Lol, thats one thing i dont have to worry about, a servo! I suspect Citroen in their wisdom set the engine back as far as possible for weight distribution and in the absence of a servo meant they could do just that. Buggers

 

I sold my old turbo with manifold, including a 65k engine for £200 quid, a bit of a bargain i though, it was by chance i found such a low miles lump with a fresh clutch and good bits.

[wracing 19]

i think that there is quite a bit of miss information on this thread. before you decide on upgrading your turbo compressor wheel you need to understand the effect on your boost response/threshold. to say that the exhaust side is restrictive is half the story to quote garrett...

 

Turbine A/R - Turbine performance is greatly affected by changing the A/R of the housing, as it is used to adjust the flow capacity of the turbine. Using a smaller A/R will increase the exhaust gas velocity into the turbine wheel. This provides increased turbine power at lower engine speeds, resulting in a quicker boost rise. However, a small A/R also causes the flow to enter the wheel more tangentially, which reduces the ultimate flow capacity of the turbine wheel. This will tend to increase exhaust backpressure and hence reduce the engine's ability to "breathe" effectively at high RPM, adversely affecting peak engine power.

 

Conversely, using a larger A/R will lower exhaust gas velocity, and delay boost rise. The flow in a larger A/R housing enters the wheel in a more radial fashion, increasing the wheel's effective flow capacity, resulting in lower backpressure and better power at higher engine speeds.

 

When deciding between A/R options, be realistic with the intended vehicle use and use the A/R to bias the performance toward the desired powerband characteristic.

 

Here's a simplistic look at comparing turbine housing geometry with different applications. By comparing different turbine housing A/R, it is often possible to determine the intended use of the system.

 

Imagine two 3.5L engines both using GT30R turbochargers. The only difference between the two engines is a different turbine housing A/R; otherwise the two engines are identical:

1. Engine #1 has turbine housing with an A/R of 0.63

2. Engine #2 has a turbine housing with an A/R of 1.06.

 

What can we infer about the intended use and the turbocharger matching for each engine?

 

Engine#1: This engine is using a smaller A/R turbine housing (0.63) thus biased more towards low-end torque and optimal boost response. Many would describe this as being more "fun" to drive on the street, as normal daily driving habits tend to favor transient response. However, at higher engine speeds, this smaller A/R housing will result in high backpressure, which can result in a loss of top end power. This type of engine performance is desirable for street applications where the low speed boost response and transient conditions are more important than top end power.

 

Engine #2: This engine is using a larger A/R turbine housing (1.06) and is biased towards peak horsepower, while sacrificing transient response and torque at very low engine speeds. The larger A/R turbine housing will continue to minimize backpressure at high rpm, to the benefit of engine peak power. On the other hand, this will also raise the engine speed at which the turbo can provide boost, increasing time to boost. The performance of Engine #2 is more desirable for racing applications than Engine #1 since Engine #2 will be operating at high engine speeds most of the time.

 

I would go for programmable management BEFORE to upgrade your turbo. the std management is far to safe in my view

 

you need to decide what you want your car for, road car with the odd track. or track only.

 

my 8v on a t3/t25 hybrid with nitrous+ignition antilag is a pain in the arse to drive on the road.

 

james

Edited October 25, 2009 by wracing

[jonnyturbo 3]

from engines iv seen with just a hybrid turbo it doesnt seem that bad? also with it being an 8v and torquey wouldnt that balance it out somewhat? what overall mods have you done to your engine wracing?

 

 

btw what happened to this thread ? i was hoping you wouldnt give up

 

http://forum.205gtidrivers.com/index.php?s...05564&st=80

Edited October 25, 2009 by jonnyturbo

[Guest Kidmans]

The above does mainly state a lot of info about the A/R of the turbine housing and not so much about the compressor side, which i have changed on mine.

 

The spec of the turbo is now identical to that of a Rover T16 Turbo, which uses the same A/R on both compressor and turbine as the PSA lump but a bigger trim compressor wheel. The performance of that engine is not too dissimilar low down to mine, max torque acheived at 2100rpm which is identical believe it or not.

 

I don't profess to know a huge amount about the exact workings of a turbocharger but i have a rough idea, which is why i took the advice of the chap who carried out the mod to my turbo. For the cost (£100) it would of been silly not to have something done to the turbo whilst it was out. He actually thought it was for a XUD9 TD The compressor wheel in size was comparable with that of an R5 GTT, which as i'm sure you all know is a 1.4!

 

By fitting the bigger compressor wheel, i hope to lower the inlet temperature, and the turbo should not be working as hard. Heat is what kills turbocharged engines and reduces power, so it seemed a sensible thing to do before i consider looking at the engine management.

 

Sadly, i dont have that sort of budget for aftermarket EMS, so i will be looking at a decat next, to help reduce any restrictions on the turbine side and this should help with spool up and lower EGT. In theory Beyond this, i need fundage and tbh, i am fighting a losing battle with the weight of the car. The Maestro fulfils my need for brute power and the Xantia will always be a large, heavy family car but with indecently good handling and nimbleness.

 

Fitting a 15G sounds great, but i would be pretty certain in saying it has a bigger turbine A/R, which will affect the boost threshold. One of the things i like about the standard engine is its ability to pull like a diesel from low revs, give a mid range punch but what it lacked was much ommph over 5k. This could quite easily be looked at as a characteristic of an 8 valve turbocharged engine but, i know it can go better and the standard turbo and manifold was definatly not designed for giving good bhp.

 

All i wanted was a small upgrade that would not change drastically the characteristic of the original set up. Once i've done some proper driving i will know for certain if the bigger compressor wheel has made a difference. But as said, if i wanted big bhp and sod driveability, i could of put a much bigger specced turbo on there.

[wracing 19]

its not as easy as just upping the trim. a/r of the compressor doesn't really effect anything. its difficult to get an all rounder, to be honest. the manufactures actually got it quite right to start off with I think. which is why i said managment. as this is not an option, increasing your inter cooling capacity surly the best way?

 

contact honeywell garrett directly they can give you compressor and exaust maps for all the turbos they have produced. this is the only way to 'spec' a turbo to your car.

 

i haven't given up yet, I've had a really big car accident, just got out of hospital, trying to face getting back on the car. had a head on with a someone which was overtaking he passed away, having difficulty getting back on the car. car spec is on my build tread thats been linked.

 

james

[Issam 0]

contact honeywell garrett directly they can give you compressor and exaust maps for all the turbos they have produced. this is the only way to 'spec' a turbo to your car.

Doubt that will happen Mate...

Honeywell/Garrett is not exactly your local hardware store where you can just ask them for a map...

 

if its not on turbobygarrett.com then you will have to figure it out yourself.

[wracing 19]

and how are you going to figure it out? with a map maybe?

 

every time i have contacted them they have been very helpful.

[Guest Kidmans]

I'm now happy this has been a success in giving me the extra ommph i wanted. No more power dropping off sharply as before once it hits 5k, nice and steady 12psi till 6k and great mid range punch. The only problem i have is a bit flat coming onto boost in the lower gears, then it kicks. Would help if i had more than 2 gallons in the tank, the fuel light is on

[jonnyturbo 3]

what was the power before and now after? made a difference?

[Guest Kidmans]

what was the power before and now after? made a difference?

 

 

I didnt have a result before, because the manifold gasket was blowing so bad and unknown to me, so was the manifold. This happened over a course of about 6 months.

 

Having had the car for a year now i've learnt how the car performed, so would notice any difference in the real world. In reality, i would say no more than about 10-15bhp, it is after all just a compressor upgrade not turbine which is where the power is gained.

 

It was a small stepping stone rather than a giant leap because as mentioned, i didnt want an engine that had increased lag and masses of top end wallop as it is a car used on the road 99% of the time.

 

I only paid £100 for the turbo to be 'upgraded' and after yesterdays drive i do not regret spending that! Its a shame the turbo is not easily accessible on mine as in future i may want to upgrade, but for now i'm a happy man as it helps this heavy beast get a move on!

[jonnyturbo 3]

not accessible to me neither mine created its own dent in the bulkhead