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My brother had a 90 740 turbo, drove it to texas on the way to boot camp and went up a hill near arizona and boom turbo blew up.. sold it to some mexican for like 100 bucks...
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Originally Posted by rmriggin' post='838199' date='Sep 23 2006, 12:19 AM
I am having problems finding out safe exhaust upgrade options and intake mods. I have not been able to find out if it would be safe for the stock efi system to go with larger exhaust or intake. I keep reading about people installing complete 3" or 2.5" systems with high flow (or no) cat but none of them mention anything about having to do fuel mods with the exhaust upgrades. Anyone know? From what I could find it appears that no upgrade chip was offered for the 1987 740 (besides the bogus ebay mods). Right now I need to at least do the muffler but I would like to know what my "safe" (ie not having to worry about detonating) exhaust options could be. I got a good resource for exhaust so if I am able to go either 3" or 2.5" complete I could have it done cheap as long as I had the correct downpipe flange for either size. I am pretty sure the 850 turbo was the first model to have a fuel cut in regards to boost pressure, thats why I had to chip mine to safely raise the boost. I would buy a cheap or used boost guage, to figure out what your stock boost pressue is. Then raise it up to where you feel safe. Personally I would run a 2.5 cat back system, once again that is what I had on the 850. I have only seen wild setups running a 3" systems. Also on the 850 the intake was seldom modded. Most people just used a K&N panel filter. Lots of 850's with stock airbox and a k&N pushing and going over 300 fwhp. I know thats a lot of 850 references, but thats all I am fimiliar with. I think you will a to put a waste gate bleeder or boost controler to raise the boost, even with the cat back I dont think my gain boost went up over 1 psi. You coming to Izzys. ? |
I wont be able to make it to izzy's. I know that I can put in different injectors, do the resistor mod to the AMM, adjust the AMM after the resistor mod is done. I will probably get a manual boost controller for cheap, borrow a vacuum pump to set the boost at like 12psi. The stock intercoolers are good up to 14-15PSI but the transmissions in the volvos are the stopping point when going for big HP. I believe that the RX-7 low impedence injectors are a direct swap (maybe find a set of 680s from 2 SEs). More than likely I will just do an exhaust (punch out cat and get a traight through muffler), up the octane from reg to medium grade, then probably just up the boost to 10PSI and still be safe. Somewhere down the line I will upgrade from the 2 fuel pumps to just a single walbro. I checked for vacuum leaks and found none (because there is the very slightest ocilation at idle only maybe 10RPM or so but being a mechanic I notice that stuff), but I noticed pulsations in the fuel line at the filter so I the fuel pump is going to need replaced sometime anyways.
From what I have read the built in fuel cut is a vacuum module under the steering column that you just have to cap off to get rid of fuel cut. What the resistor mod does is makes the ECU be able to use the extra fuel that the upgraded injectors are capable of. |
One more thing
since I got the mitsubishi turbo there are a bunch of write ups I have found on cheap (or free) things you can do to increase boost. With the mitsubishi turbo I can crush the CBV, then dril and tap in a vacuum line to the base of the CBV to make a fast acting CBV that can support up to 30PSI without leaking. From what I hae read the mitsubishi turbos seem to be stronger and larger than the garretts offered. |
LOL told you you would own a turbo one day!
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