Island Twin Turbo system

[jfirios]

i dont see how doing a stage one or stage two upgrade will effect putting on a turbo unit.

[Delorean Industries]

it will because naturally aspirated engines are not set up for boost. Our Spec II offering just like Stage II uses camshafts cut for a non boost application.

For those that want turbo set ups though. That is what we do

[jfirios]

so josh, since I just did the stage one on my car and the engine is still stock I can put a turbo on it. or would it be better to just keep in NA and put on the dual cone filter CAI system

[louielouie2000]

so josh, since I just did the stage one on my car and the engine is still stock I can put a turbo on it. or would it be better to just keep in NA and put on the dual cone filter CAI system

You can't put a turbo on a stage 1 equipped car. Turbos require special exhaust manifolds (which the turbo chargers themselves are seated to), and you just replaced your manifolds with headers. You could always remove the stage 1 exhaust and sell it, then convert the car to a turbo. But that's a pretty big money losing proposition. You're better off with continuing to warm up your naturally aspirated engine through things like cold air intakes, racier camshafts, better ignition components, possible EFI, etc.

[jfirios]

your right.

[bunni]

I was thinking about doing a stage I in the near future (currently tearing apart my engine), and maybe down the road research in to getting a turbo set up, glad I spotted this. Which would be better performance/stability/longevity/whatever wise? Was never a car guy until the DeLorean turned me in to one so I am still learning the ropes. I am not trying to get a ridiculous boost in hp, but it would be nice to have a little more kick behind the wheels.

-Kris
#4222

[jfirios]

I would say, along with some of the other people here the best and safest for the engine is to keep it NA and not do the turbo. There is a lot that can be done that will increase the HP, including the stage 2 upgrade, which includes the stage 1 exhaust upgrade. Putting in a CAI will help plus make the engine sound cooler, but be careful, i blew my last engine in my other car by running through a puddle and sucking water up through the intake and frying my engine. Not a cheap rebuild.
My advice is research research research before doing anything.

[DMCVegas]

Imagine that<sarcasm>. You always have to keep in mind whom you are talking to and what they market and/or sell. Kinda hard to sell a Stage 1, Stage 2, or Stage 3 (eventually), or now apparently electric upgrade (Stage 4?) to someone wanting a turbo.

Point taken. Although something else to consider is that with the Island Twin Turbo's set up, it's very prone to blow seals in the turbos.

Usually with forced induction (be it exhaust driven turbos or a belt driven supercharger) the compressor is mounted upstream of the Throttle Plates. This is rather important. As you decrease engine speed, Manifold Vacuum between the intake valves and the throttle plates increases. This is of course most noticeable when you WOT and then dump into Idle as the engine is sucking in a large quanity (CFM) of air, and suddenly the throttle plates stop supplying it, and the engine gets starved for air and slows down as a result. This is why of course spring-loaded Bypass Valves are mounted onto the Stock Throttle Plates (it could cause a lean condition that not only increases NOX emissions but throws the LAMBDA into a panic), and if the vacuum becomes too much they can simply open up to slowly balance things out. And with forced induction, excess pressure builds between the throttle plates and the compressor, which is no big deal since compressors and the system that utilize them are meant to deal with this and are designed accordingly.

Now like I said before, compressors are usually mounted ahead of the Throttle Plates. But with the Island Twin Turbo setup, they're AFTER the throttle plates. So in situations where you got from WOT directly to Idle the Compressors themselves then get exposed to Vacuum. Turbos don't like this because they were never designed to be exposed to negative pressure. As a result of subjecting a Turbo's compressor to Vacuum, the Turbo itself can blow it's seals and seep oil into the intakes. This is why in the past people tended to think that the turbo charged PRVs were fragile and had too many problems because they burned oil. They just assumed it was always blow-by from bad piston rings which really wasn't the case. If you come across an old Island Twin or a Single BAE and it's burning oil, it's most likely not an engine problem at all, but just a turbo that needs it's seals replaced. And if you know this, you'll be able to more confidently negotiate it's price

Now if I can play Devil's Advocate here for a second... No doubt that places want to make money off of customers. And the best way to do that is to give customers exactly what they want. Certainly with new products there is probably a desire to sell them of course. HOWEVER with the Island Twin Turbo kit there is also something else here to consider. The kit itself due to the placement of the Turbo Chargers is not nearly as hardy as the other options available as it doesn't stand up as well to abuse (blown seals, Coking of the Turbos, etc). At the same time after maybe a year or so of installing these kits, DMCGG (or DMCCA, whatever acronym we use now) is going to get back angry customers who are pissed that their cars are burning oil. Now while some people may understand what's going on here and reasonably accept it, most people are not even if they do understand. If you spend thousands of dollars having a turbo installed, or even just buying the parts to install one, you're going to be pissed that now you've got to prematurely service parts. In a word, you're gonna be frustrated. And from Don Steger and Danny's point of view, they're going to have to deal with frustrated customers who are going to want to take anger about this whole situation out on them. They'll get wrongly blamed for the poor design malfunctioning even though they had noting at all to do with it. This gets even worse if you have to explain that a customer also made the problem worse through abuse. Customers get pissed and their reputation takes a hit.

So I totally understand why they would steer customers away from the Island system, because I would too.

[David T]

As I see it the seal problem is overblown. The bigger problem is control. The system is on the verge of detonation at 5 lbs boost. At the right conditions, a sticky actuator, high ambient temps, low octane gas, a lean fuel condition, etc, if enough conditions happen together you over boost the stock pistons and THEN you see OIL! The other situation is an owner who loves the feel of the turbos but is not happy with only 5 lbs boost so he figures he can turn it up "just a little bit". He gets away with it for a while but eventually he blows the lands off the pistons. With modern engine management systems you can get much better control over the whole engine and all of the systems so as to make a turbocharged setup much safer in terms of longevity. Mechanically the Island system is pretty simple but it never had what I would consider a good control system. At a DMA dinner we had John Conway as a guest speaker. He was hired onto the Island turbo project to try to tune the system to make it work. He admitted he was always nervous about detonation which is why he modified the mechanical advance in the distributor to limit the advance.
David Teitelbaum