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Discussion Starter · #1 ·
Im in the current process of turboing the non vtec d15b i have. I had a boosted y7 in the past but it suffered a total castisrophic breakdown hahaha. First question i thought d15b were jdm vtec motors but mine is non vtec. What can u tell me about this motor? Can i put vitaras on cheap econo forged rods or do they have those smaller/weaker cranks that some d15's have. The secound question is im gonna run a t3 .42/.48 from a volvo the exhaust flange has a weird circular imprint on it. what can i do to make sure i get a good seal between the exhaust flange on the turbo and my manifold? Im very close to having all my parts arrive in the mail. I am hoping to hit 175whp+- on 7-9 psi with a chipped ecu. The last question is the downpipe situation. Should i run a 2.5 or a 3" i havent ordered one yet because im not sure what i need. i know 2.5 is sufficient but 3" would be good for the future plans of 250-275whp+-. Can running a very large downpipe on a smaller turbo and small hp d15 turbo be bad for performance and spool characterisitcs? Thanks guys!
 

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First question i thought d15b were jdm vtec motors but mine is non vtec. What can u tell me about this motor? Can i put vitaras on cheap econo forged rods or do they have those smaller/weaker cranks that some d15's have. The secound question is im gonna run a t3 .42/.48 from a volvo the exhaust flange has a weird circular imprint on it. what can i do to make sure i get a good seal between the exhaust flange on the turbo and my manifold? Im very close to having all my parts arrive in the mail. I am hoping to hit 175whp+- on 7-9 psi with a chipped ecu. The last question is the downpipe situation. Should i run a 2.5 or a 3" i havent ordered one yet because im not sure what i need. i know 2.5 is sufficient but 3" would be good for the future plans of 250-275whp+-. Can running a very large downpipe on a smaller turbo and small hp d15 turbo be bad for performance and spool characterisitcs? Thanks guys!
First off, are you sure it's just a D15B and not a D15B2 or B7? or even a B8?
The cranks aren't weaker persay, just a smaller stroke.

Copper gasketing will help seal in exhaust situations such as manifold to turbo and turbo to downpipe.

As far as the Downpipe is concerned, the bigger the better. A 3" will help your turbo spool quicker. Just make sure to keep a full 3" exhaust so that you have no restrictions downstream.
 

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Discussion Starter · #3 ·
yeah im positive, the block is stamped d15b. nothing after the b which is why i was confused. Yeah a copper gasket might work let me post a pic of what im talking about.
 

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Discussion Starter · #4 ·
i got rid of that manifold awaile ago in favor of a spoolin log. You see that recessed circle in the casting? areu sure a gasket would take care of that?
 

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for your first and second question...i cant really help you there. but as for your third question, i say go for a 3" downpipe, as i am getting one next week and as it was shown to me today by my buddy 3" definitely makes a difference :TU: . i am also d15b7 setup and running a smaller turbo compared to you, a tdo4-15g and in the future if possible i would like to be in a 220-250whp range. but i must say for stock b7 i was extremely happy and at the same time happy of the time i got for my 1/4 mile. goodluck man, and keep us posted.
 

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i used the same turbo... i miss it, but that shit will leak
u need to either

a. deck the hot side flange
b. get a volvo flange
c. make adapter plate
d. get another hot side

i made a flange it still leaked a lil ig i did it over agair id use 1/8 inch steel
 

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The non vtec d15b Came with dual carbs. From looking at the internals when I took mine apart, i was pretty happy with all i saw. Internals look pretty stout. Taken it to 8000 rpm quite often N/A with just factory internals. No oil leaks. No smoke. Its a good motor.
Don
 

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Discussion Starter · #11 ·
i have a d15b stamped block straight d15b. There no carbs. Its fuel injected. The motor came from a 5th gen civic i believe. It seems to be a d15b7 but its stamped d15b on the block which is what throws me off. Anyone got any ideas about that turbo and the exhaust flange situation? bump for some useful information
 
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