RE: [DML] what kind of turbo?

["Marc A. Levy" <malevy@xxxx>]

I can't give an educated answer, but I can talk from experience specific toDeLoreans.

06068 had a Island turbo kit on it (Blow-By, as you say), compared to 01860which has the Legend engine (Blow through). The Legend is running about 2Lbs more then the Island (it could probably take more, but I don't want to risk damage to the engine!), so it may be an unfair comparison but the Legend has less lag than the Island setup. Both engines use the same turbochargers, but the engines themselves are very different internally so you decide if it is a accurate comparison or not.

On the Legend setup, the turbos have no restriction from the atmosphere (other than the air filter). The restriction is downstream at the throttle plate. This configuration may allow the turbos to create a positive boost onthe pressure plate when they are not wide open. When the throttle is snapped (lets say you go from 2K rpm to 4K rpm) there is already a bit of boostthere to get it going faster. Kind of like releasing the Hoover Dam (Well, maybe not that big!) The only drawback of this system is there is not a good place to pull vacuum (for the brake booster, auto transmission, AC controls, and so on).

The Island setup has the turbos placed downstream from the throttle plates.This system restricts air to the turbos and does not allow there to be a positive boost "ready to go" on demand.. Of course, there is plenty of vacuum between the throttle plates and turbo's!

Hopefully someone else will have more detail than I do.

> -----Original Message-----
> From: Dick Ryan [mailto:deloreanbiker@xxxx]
> Sent: Friday, August 02, 2002 2:51 PM
> To: dmcnews@xxxxxxxxxxxxxxx
> Subject: RE: [DML] what kind of turbo?
> 
> 
> This brings up an interesting question that one or
> more of you may be able to answer.
> 
> Every supercharger I have seen blows the forced
> induction right through the carb or into the throttle
> body. Many turbo's do the same (the turbo in
> question and the Legend engine in Marc's, plus 502). 
> Harry Ward who had one of the first aftermarket
> turbo'd cars was also a blow-thru.
> 
> HOWEVER, the BAE single turbo kit and the Turbo
> Manifold Twin kit are "blow-by"; ie, the forced
> induction is blown into the intake manifold to
> supplement the air pulled into the throttle body.
> 
> WHY?
> 
> Is there a performance advantage of one approach over
> the other? Or, does it have to do more with available
> engine compartment space and/or the ease of hooking up
> one system over the other.  
> 
> I'd sure like an educated response.