another turbo question

[66shelby]

One thing I haven't seen mentioned Yodabiri.

The GN setup is a draw thru system IIRC.

You can't (shouldn't) use an intercooler with this system. A backfire could be hazardous for you and others within a radius.

X, I am still deciphering your response.

I am in the final stages of fabbing a header. This picture is from a while back.

Can anyone get me measurements for a T4 flange? I plan to flange the header T4 and make an adapter to the T3 if possible.

One reason why I am concerned about experimenting too much is that I will have to purchase one of these.

Close to $100 to have an integral wastegate and give the exhaust a short path. With everything you have to buy from ignition to fuel systems, this gets to be a costly proposition, no matter how much of the work you can do for yourself. It is great to have all the input.

 

[Bort62]

The GN was draw-thru EFI.

Also, a Grand National is going to be an unlikely if not impossible car to find in a junkyard. They are big-time sought after.

T4 flange dimensions should be avaliable on the internet.

 

[yodabiri]

When i was there i thought i sow something resembling a gn. anyways i am gonna have a blow through system. and i will fab up a header also when i get to practicing my welding skills.


Thanks for the responses

 

[Bort62]

The GN was draw-thru EFI.

Also, a Grand National is going to be an unlikely if not impossible car to find in a junkyard. They are big-time sought after.

T4 flange dimensions should be avaliable on the internet.

I am an idiot, blow through.

 

[wallaka]

Some of the earlier T-types were draw-through with a Q-jet. The later ones were EFI.

 

[yodabiri]

So i will try and track down a gn turbo, and if i cant then i will try to get a similar sized turbo somewhere else. Just out of curiosity does anybody have a turbo they would like to sell? something within a reasonable range (preferably no more than $500). It would need to be suitable for a 250 engine. I will fab up the header when i get a welder and get to practicing with it. I have been looking at welders and they usually need 220V which i dont have in my garage. But anyways I was just wondering if it is most benefitial to try and design an equal length header or just go with the same type of design that Does10s has. I really like his design (though it isnt as efficient as it could be from what i have read), but i dont really want a J pipe for some reason.

Thanks for the replies!

 

[hasa68mustang]

yes the equal length will be better but will make the header alot more interesting to make.

 

[yodabiri]

Hey Im up for a challenge. I dunno if I would be able to make one or not, but like you said it is definitely interesting to make.

Thanks for the response!

 

[XPC66]

I know that science says that nice equal length headers to a turbo is the go, but in all honesty I can't say it makes things better. I tend to use the cast iron manifold and cast weld a flange on. The short cast iron runners hold the heat well, keeping the pressure up, which is all important for the turbine.

On the otherhand the most important part of the exhaust, that really gets results, is to have a good sized radiused dump/down pipe. You know when you get that right on stock turbo engines when the wastegate can't stop creep and the port has to be bored out.

 

[grocery getter]

I went down this road and what wallaka said makes sense. work with what you have. if you really want to go turbo do the J pipe, get it running and then use your experience to build the header. as linc and hasa68 have shown, turbos make up for a lot of the sixes short comings. why would you want to worry at this stage about whats more efficient. save that for later after you've played and learned.

get familiar with turbo maps, you'll be able to make your own decision on size. everyone has different ideas of the right turbo.

Edit---> about does10s header, he built it that way for fitment. I had one bolted up. just relocate the battery, pipe it up and you have a clean install.