Making my own downpipe

Semper_Fi · 05-04-2010, 02:59 AM

my neihbor builds 7mgtes and races the shit out of them... he said he wants to put a washer in my wastegate and do my exhaust 3 inch piping. Im currently rebuilding the engine, practically brand new. Oem everything. Well current question is... Any input on the making the downpipe?
Also, will my engine be able to hold the washer in the wastegate? i want to put a little more psi in the block, but have never messed with a stock turbo engine. My last build was a h22a4 97 honda prelude, which on 5psi, boosted to 300hp. 12k in it(which i regret), and a list of mods that make a builder wett his pants. tial, garret, synapse, rc engineering, prosport, wideband from aem... lol... list goes on and on. And an rx-7 which came allready with an msd 2 step in it.

Long story short for those who dont want to read...
Head Gasket new... oem speck.
Washer in wg good or bad idea?
making own exhaust good or bad idea? Why?
2 step? how and good or bad?
Thanks
Semper Fi

supraflymkiii · 05-04-2010, 03:30 AM

When you say put a washer in your wastegate I think you mean shimming the wastegate actuator with washers. If you're rebuilding the engine I would break it in first and after its broken in go ahead and shim the wastegate as it will allow you to boost higher and hold boost longer. As for the downpipe I don't see why you wouldn't want him to make one if he can make it 3" from the turbo and eliminate the turbo elbow that would be awesome. That is if he charges you a reasonable price otherwise you might as well buy one. With everything rebuilt back to stock specs you shouldn't have a problem doing bolt on mods or pretty much any mods for that matter. Once you start pushing for over 400hp you might want to look at forged internals but the stock bottom end in the 7m is very strong if maintained well.

Semper_Fi · 05-04-2010, 04:25 AM

Quote:

Originally Posted by supraflymkiii

When you say put a washer in your wastegate I think you mean shimming the wastegate actuator with washers. If you're rebuilding the engine I would break it in first and after its broken in go ahead and shim the wastegate as it will allow you to boost higher and hold boost longer. As for the downpipe I don't see why you wouldn't want him to make one if he can make it 3" from the turbo and eliminate the turbo elbow that would be awesome. That is if he charges you a reasonable price otherwise you might as well buy one. With everything rebuilt back to stock specs you shouldn't have a problem doing bolt on mods or pretty much any mods for that matter. Once you start pushing for over 400hp you might want to look at forged internals but the stock bottom end in the 7m is very strong if maintained well.

Thanks!!! yeah he aint charging me to do the work... we go way bak... i helped him build his 10 second corrolla, then called it when he was gonna breake it... straight pipe wont cause a problem will it?

btwilson86 · 05-04-2010, 07:34 AM

From what I read, shimming the wastegate isn't a good idea. Basically, it puts extra stress on the wastegate actuator, causing it to fail more quickly (and you definitely don't want a broken wastegate actuator). I think a safer alternative would be to just install a MBC or an electric one in the vacuum line that runs to the w/g actuator

supraflymkiii · 05-04-2010, 02:13 PM

If you don't shim it with to thick of shims it should be alright I ran my 87 Turbo shimmed with like 5/16" thick spacers which gave me about 12lbs of boost and held it almost all the way up to redline and I ran it that way for a few years with no problems and no change in boost. As for the straight pipe question yeah that should be fine you might want to throw some sort of muffler on the end though otherwise they're pretty damn loud straight piped.

Semper_Fi · 05-05-2010, 04:37 AM

Quote:

Originally Posted by supraflymkiii

If you don't shim it with to thick of shims it should be alright I ran my 87 Turbo shimmed with like 5/16" thick spacers which gave me about 12lbs of boost and held it almost all the way up to redline and I ran it that way for a few years with no problems and no change in boost. As for the straight pipe question yeah that should be fine you might want to throw some sort of muffler on the end though otherwise they're pretty damn loud straight piped.

Thanks man. Im actually about to put the one i had on my last project car on it. Its a 4inch hks of a nissan skyline r34vspec... My last car was a honda prelude turbo. I baught the pipe of some kid i was killing in mw2.

Ok so thanks to cre, ima attempt to build a boost controller!!
Reps to cre for the help.
http://www.gusmahon.org/html/boostcontrol.htm

05-04-2010, 02:59 AM	#1
Semper_Fi 3" Exhaust Join Date: Apr 2010 Location: Kissimmee, FL Posts: 72	Making my own downpipe my neihbor builds 7mgtes and races the shit out of them... he said he wants to put a washer in my wastegate and do my exhaust 3 inch piping. Im currently rebuilding the engine, practically brand new. Oem everything. Well current question is... Any input on the making the downpipe? Also, will my engine be able to hold the washer in the wastegate? i want to put a little more psi in the block, but have never messed with a stock turbo engine. My last build was a h22a4 97 honda prelude, which on 5psi, boosted to 300hp. 12k in it(which i regret), and a list of mods that make a builder wett his pants. tial, garret, synapse, rc engineering, prosport, wideband from aem... lol... list goes on and on. And an rx-7 which came allready with an msd 2 step in it. Long story short for those who dont want to read... Head Gasket new... oem speck. Washer in wg good or bad idea? making own exhaust good or bad idea? Why? 2 step? how and good or bad? Thanks Semper Fi

05-04-2010, 07:34 AM	#4
btwilson86 Super Moderator Join Date: May 2007 Location: Billings, Montana Posts: 1,034	From what I read, shimming the wastegate isn't a good idea. Basically, it puts extra stress on the wastegate actuator, causing it to fail more quickly (and you definitely don't want a broken wastegate actuator). I think a safer alternative would be to just install a MBC or an electric one in the vacuum line that runs to the w/g actuator __________________ 1989 7MGTE R154 Targa Top White Package w/Blue Interior Driftmotion 57trim CT26, Upgraded Intercooler, 2.25" Hard Pipes, 3" Turbo Back Exhaust with Test Pipe, HKS VPC w/GM 3 bar MAP sensor, APEXi S-AFC, Walbro 255lph fuel pump, ProSport EVO Series Boost / Fuel Pressure / AFR gauges, Lotek a Pillar Gauge Pod, HKS Type 0 Turbo Timer, Eibach Lowering Springs, Tokico Illumina II TEMS struts, custom powder coated Motegi Racing TrakLite wheels

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05-04-2010, 03:30 AM	#2
supraflymkiii 3" Exhaust Join Date: Sep 2005 Location: Menasha, WI Posts: 63	When you say put a washer in your wastegate I think you mean shimming the wastegate actuator with washers. If you're rebuilding the engine I would break it in first and after its broken in go ahead and shim the wastegate as it will allow you to boost higher and hold boost longer. As for the downpipe I don't see why you wouldn't want him to make one if he can make it 3" from the turbo and eliminate the turbo elbow that would be awesome. That is if he charges you a reasonable price otherwise you might as well buy one. With everything rebuilt back to stock specs you shouldn't have a problem doing bolt on mods or pretty much any mods for that matter. Once you start pushing for over 400hp you might want to look at forged internals but the stock bottom end in the 7m is very strong if maintained well.

05-04-2010, 02:13 PM	#5
supraflymkiii 3" Exhaust Join Date: Sep 2005 Location: Menasha, WI Posts: 63	If you don't shim it with to thick of shims it should be alright I ran my 87 Turbo shimmed with like 5/16" thick spacers which gave me about 12lbs of boost and held it almost all the way up to redline and I ran it that way for a few years with no problems and no change in boost. As for the straight pipe question yeah that should be fine you might want to throw some sort of muffler on the end though otherwise they're pretty damn loud straight piped.