VNT Turbo; EGTs concern
 

Hi all,
I am working on designing an engine for the FSAE competition, and Garret will supply you with a free turbo for the competition. One of these turbos being a VNT (Variable nozzle turbo), but it likes to stay at a tempature of 825C* . Here is a link to the page. Get Sponsored - Honeywell Turbo Technologies.

So my question to you all is: How do i get my EGTs low enough to not fry this thing?
A few thoughts i was having was spraying CO2 into the exhaust to cool it (or some other cooling gas) This would require a large supply on the car. Or run heat sinks off of the exhaust, (These could potentially be very dangerous) .

Or how would i get the EGTs down using tuning? If i run this thing to rich it will clog the vanes and have the same effects.

Any advice is greatly appreciated.

Steven

For the competition the only appliable rules are:
There is a 20mm restrictor, has to be under 610cc , rules state that sequence must be throttle~>restrictor~> Turbo~> intercooler~> engine

I was thinking of running a smaller cc motor (less weight) and trying to make the same power using FI as the GSXR motors, and such.

Fuel is one of the factors. Adding a little more can help to bring them down. Do you have any idea where the temps are now? 825*c is really on the higher end as is. Do you have a link to the specs/restrictions for the build?

Advancing your timing will help as well. It gives more time for thermal dissipation inside the cylinder, but then you are running a hotter cylinder which can lead to pre-ignition.

Right now we have no set engine we are using, we are still trying to figure out if we want to go with FI. The VNT turbo is an option because it is free and because there is potential.Running to rich will clog the vanes as well, but tuning is definitely a part of the solution. the restrictions are what i posted in the first post
610 cc, 4 stroke, with a 20mm restrictor.
heres a link to the rules for the really interested . If you go to page 37 it shows the whole rule set.
http://students.sae.org/competitions...0fsaerules.pdf

So run the gt15. You will not need to go rediculously rich to get your egt's down below 825. Especially if you place the turbo a little further away from the exhaust ports.

Water injection will lower Egt. Rules won't let you spray it into combustion chamber, but some marine application spray it into exhaust to lower egt. Devils Own sells a diesel controller that injects based on egt, a simple switch when egt hits a certain point maybe enough though. Inject just water instead of 50/50 methanol mix. The water should steam clean the vanes rather then clog them.

Definitely looking into this! Thanks