As promised we will this time discuss turbo headers.What are the different models and what are the advantages per type. This way you can easily see which type is the best for your setup.
Log-type
This is the cheapest header. These headers have as advantage that you can easily keep airco and powersteering. Because of the short runners the turbo will spool up pretty quickly. An advantage because they are made out of cast iron is that they are unlikely to break. The main disadvantage is that they are not made for a high flow. Because of this the top-end power can be limited. However, there are some models for sale that flow well on high rpm's. A log type manifold is perfect for a relatively mildly built engine or when you want to have more power in the bottom of the rpm range.
Mini Ram
A miniram header has a 4-1 setup. This has as a result that the flow is inchreased and still be pretty small and cheap. They are a good mix between size and price. Because of the runners it has a relatively good flow at low rpm. This manifold is best suited for people that want a turbo daily with an inchreased flow in comparison to a log type.
Ramhorn
The runners are almost equal with a ramhorn header. They are longer than a mini ram however, which slows down the spooling rate a bit in comparison to a log type. Because the runners are almost equal, the turbo will have more top end flow. With this type of header it is usually comparatively hard to mount a big downpipe or reach the turbo easily.
Topmount
With a topmount the runners are usually as good as equal in length. Because of this all pulses enter the turbo equally instead of overlap with other manifold types. This has as result that the energy gets used most efficient. Therefore it is possible to install a bigger turbo and a larger sized downpipe. If you want to have a huge turbo the size of a borg warner than this is your best and probably only choice.
To summarise:
Quickest spool:
1. Log
2. Mini Ram
3. Ramhorn
4. Topmount
Best potential for top end power:
1. Topmount
2. Ramhorn
3. Mini Ram
4. Log
It is also recommendable to have two separate wastegates if you decide to go for a 4-2-1 setup.
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