Stock Turbo With External Tial 38mm Wastegate ?!
 

We did a another turbo swap on a 90 N/A for a customer. We built a custom exhaust along with a hand full of other mods for it. (TurboXS BOV, Powder coating, custom 3" aluminum intake, HR soiled motor mounts, etc, etc) Of course with the high flow exhaust, the turbo shined through with the well know over boosting / creeping issue associated when the exhaust is upgraded. We 1st attempted to rid the problem by porting the internal wastegate & devoicing the wastegate from the exhaust flow. This involves adding a divider in the exhaust housing to separate the exhaust from the wastegate. Then adding a dump tube to the back of the exhaust housing flange so the wastegated pressure can flow out, without being wrapped up in the exhaust flow. It helped but still wasn't enough to keep boost at bay.

The customer couldn't afford to step up to one of our full GT turbo kits so we came up with something for him. We dropped the stock internal wastegate all together & incorporated a Tial 38mm external wastegate to control the boost on the stock turbo. The outcome, works perfect! Boost is rock solid now with no spikes or creep. He now also has the ability to increase or decrees boost by simply changing the spring in the wastegate. And has that wicked Braaaap sound from the open wastegate.

The 1st pic shows the beginning stage of the porting to the internal wastegate. We ended up opening it allot more then shown in the pic. The main goal was to get as much pressure as possible to the inlet of Tial 38mm. The top port (rear rotor port) can be opened almost all the way to the right side.

Makes for a great way to control boost on the stock turbo for little cash.

http://i39.photobucket.com/albums/e1...margatemix.jpg

not bagging on you guys but a simple T04 setup should have been affordable, given more performance gains and would have been easier to upgrade than this setup.

yes it is unique and looks good but a bit of overkill imo.

I agree, a new turbo would of been idle but the customer didn't have the funds for a new manifold, turbo, oil & water lines, custom downpipe, new intake, couplers, clamps, fittings, etc. Going to a full T04 turbo will still require a external wastegate on top of the above if it uses a T4 turbine. A turbo upgrade costs allot more then a $200 wastegate.

Defiantly not overboard.

oh i'm sure it cost more than just the $200 wastegate. the additional flow through the wastegate is nice but the flappers can be elarged also to flow more. like i said, it is unique but there is other ways to do effectively the same with less work and cost.

it does give people ideas for doing similar upgrades though which is a good thing, i like to see more fabrication and imagination.

Ummm....

No, the cost was $200 & like $10 in steel. I'm yet to see 38mm of flapper door incorporated into the internal wastegate & gaining the benefits of adjustable boost control.

Took less then a day to do & the car was back on the road.

so do you have to port the wastegate hole if you are going to ditch the internal wastegate and put an external like you guys did?

Looks like a ported s5 turbo to me.

of course, there is no other way to get more flow. the only other alternative would have been to drill and weld the wastegate pipe off the manifold itself but i believe that would distrupt too much of the exhaust airflow, it also isn't very feasable on an S5 with the shorty manifold.

True. The S5 manifold doesn't make for a great platform to add wastegates. This is the main reason why we picked the back of the turbo. Plenty of room without creating flow restriction & without jeopardizing the manifolds integrity.

If nothing else, this will give other people more ideas & avenues to explore when trying to keep their boost under control. It's important that we think out side the box sometimes.

yep, it's just i feel it is sort of a big patch for a bigger turbo. if people don't have the money for the right equipment i require a deposit for earmuffs because they are gonna blame you when things break.

The whole reason for the external gate was to stop the car from braking. If we left it at a flapper door & porting mod, it would only be a matter of time before the car popped the engine from over boosting. The car has now been on the road for 4 months & no problems. Runs strong & much of that is due to the external gate. He dives it every day.

Don't get me wrong. Completely sick set ups are what we are about. We have defiantly proved that we are capable of some of the sickest stuff around. Only the best is our choice but if the customer is on a budget, you must build to that budget & if it's not possible to achieve their goals with the funds they have, they are made aware before we start anything.

For this customer, we exceeded his goals on the funds he had available. Keep in mind that he didn't even have a car to work with when he 1st came to us. We got him the car, then built & turbo swapped it for him, with mods.

Honestly though, I'm bored with N/A to turbo swaps. I think this is the 3rd one we've done in 06 & they are becoming repetitive. The only thing we have to look forward to with them now, is coming up with new ideas & innovative things to incorporate with them.

Why don't you sell this mod as a mail-order piece? Sell it with and without the Wastegate, incase a buyer has his own wastegate already? You might have to have a slightly different config for N/A-2-turbo than for TII. I know I would be interested, if the price were decent. Would be an awsome setup for a hybrid stocker.