Turbo - twin or single

[robx]

Excuse my ignorance on this one, but having read through some previous topics it would appear that some Supras have been converted to single turbo's...

Now, here's where I show my ignorance... surely 2 have to be better than one...? what advantage is gained by converting to a single...?

Cheers

Rob

[alex h]

LOL - that could cause such a messy thread http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/smile.gif
To be brief - I can explain further if needed - the two turbo's you have on your car are of a certain size (small) and they are bolted to a sequential system which gets No.1 producing boost by 1500rpm and then brings in no. 2 at about 3,500-4,000rpm.
If you want more than 450bhp you would exceed all that the stock system is capable of handling, at this point you can opt for a med-large single or a PAIR of larger turbo's but with both options you have to get an entirely new Manifold, fuel system, intake system etc as the stock systems can only run stock turbo's they are incompatible with other types and of course sizes.

Most people go single as it gives them the power they want, without the extra weight or cost of a new parallel twin system (only the stock system can be sequential).

Singles can come in various sizes able to flow 100-1000+hp. Parallel twins can too but they weigh more and cost more. but they do look nice http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/smile.gif

Does that help? Or do you want to know something more specific?

[robx]

Thats very helpful. Just one of those things that I've wondered about but never been able to find an answer...Thankyou.

Rob

[alex h]

NP mate. Please ask away. Though I'm going to move this to Engine Tuning as it's not an electrical issue http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/smile.gif

[Martin F]

Alex got in there before me, but to add..........

To take the easy one, cost................ It obviously costs a lot more to fit two turbo chargers rather than one, two wastegates, two lots of plumbing and maintenance on two turbo's if something does go wrong. Do these additional costs always outweigh any benefits, well not always as other wise we wouldn't have the TT.

The two turbos in the TT application are a good solution as they come on stream sequentially and by picking two smaller turbo's (they are both exactly the same size on the Supra TT) we can actually have positive boost from 1500rpm. Trying to do that with one turbo which was still providing a positive benefit at 5000+ rpm would be impossible (well it would have to be a dream come true for turbo designers ! ) This is also the reason why the stock turbo's begin to come inefficient when you increase the boost pressure on the std cars.

Twin Turbos (and the cost of them) do also have some benefits on V or flat engines as trying to port the exhaust gases to a common point can be tricky.

In summary (much as Alex posted) the reason some of the big power Supra's go for a single turbo is because of its simplicity and ease of installation.

Now did we tell you about the tri-turbo................. http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/outahere.gif