Mod |
Benefit |
Drawback |
Is it a problem? |
Notes |
|
Increase boost pressure
What is and How to fit an RV |
|
- Increased air intake temps
- Detonation much more likely
- Likelihood of engine failure increased
- Stock turbo limited in pressure/flow
|
ish, depends on prior modifications |
An SBC is far superior than the RV method, but an RV is much cheaper! |
Dump Valve
How to fit a DV
What is a DV |
- Get a 'tish' sound like a boy racer on gear changes
- Improve driveability
- Helps to keep turbo spinning between gear changes
- Helps to prolong turbo life
|
|
No |
Atmospheric type will foul up fuelling when changing gears as metered is vented to atmos. Recirculating type will help to correctly meter fuelTry not get a diaphragm DV - these fail more often and wear quicker than the piston type Select the correct spring or idling may be a problem - 5psi |
Fuel Cut Defencer What is an FCD?
Make & fit an FCD |
- To generate more boost than the stock
ECU will allow
|
- £ if bought, cheap to make
- Require ECU wiring diagram and a soldering iron - ECU pin out article
here
|
ish - depends if you are any good at soldering! |
Allows more boost pressure by overcoming the fuel cut level set by the ECU
~12psi (exact level varies from car to car) |
Uprate/hybridise stock turbo
Pictures |
- More power, more fun
- More efficient at a higher boost pressure
- As it is more efficient, the likelihood of detonation at higher boost pressures reduced
- Will flow better
- Will help cure the wastegate crack you probably have
- May cure the smoking at idle!
|
- £ dependant upon choice of size
- Upgrading stock turbo good for oil & water pipes and support brackets etc but not nearly as good as a GT30 or GT25 etc for power and efficiency
- Watch the size of the compressor as the stock wastegate may not be able to flow out enough exhaust gases
|
No |
Popular sizes for CT26 inducer:
42mm - 12psi (ST165)
44mm - 15psi (ST185)
48mm - 18psi (ST185 CS/RC)
48mm - 18psi (ST205)
52mm - 18psi 54mm - 24psi 56mm - 24psi
(based on Garret T04 wheel) Note - this is only a very sketchy rough guide You might also want to ask about:
- Gas flowing the wastegate
- Inconel wastegate seat, for 165
- Polishing the compressor housing
- Gas flowing the exhaust housing
- 360 degree thrust bearing
|
Fit larger aftermarket turbo |
- Much more power, more fun
- You'll probably want go for a Ball Bearing turbo...
- Less lag
- More efficient
- Able to produce more pressure and more importantly increased flow
|
- ££
- May require a custom exhaust manifold or adaptor
- May need a custom down pipe
- May require custom oil feed and drain, water cooling to/from the turbo
- Dependant upon turbo type may require an external wastegate...£
- Some way of controlling this lot - an aftermarket ECU
- Shortening the life of the stock engine, maybe not your daily driver car?
|
Yes |
By now you are into some serious power - you'll definitely need an aftermarket ECU or addon/piggyback, go for a complete ECU... Reliability shortened. Fuelling needs to be addressed, maybe larger injectors fitted, replacement/addon ECU, forged pistons may also be required etc |
External wastegate |
- Better exhaust gas flow
- Improved turbo control
- Improved power output
|
- £
- Specialist external dump valve required
- Need to fabricate a custom downpipe to accommodate the output from the external wastegate and the turbo
- You'll obviously need an external wastegate turbo. NOT the stock CT26!
|
Yes |
Expensive! |
Disable TVSV How to article |
- Better control of boost pressure
- Run same pressure in all gears
|
- Will run the same LOWER pressure in all gears
|
No |
This is normally carried out when fitting some sort of boost controller. Doing this mod without fitting a boost controller is pointless and will make the car slower! |
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