Got my freshly rebuilt and upgraded stock turbo back from Majestic on Friday. Pulled the old one today, and I'm in the process of cleaning up a little and putting it back together. I was pretty impressed with the job Majestic did on the upgrade. The compressor inlet is hogged out and polished to a mirror finish. The 46 trim wheel is quite a bit bigger than the stock one. I am really looking forward to getting it back together, but that will probably have to wait until next weekend.



Here's a pic of the upgraded compressor wheel:

Here's the stock one for comparison:

looks great

get that mother on there.

my OLD turbo was bigger it had a garret housing on it



still nice https://www.nopistons.com/forums/pub...IR#>/smile.png

We used a Majestic turbo on my buddy's S5 T2...looked like urs, boosted like stock and wouldn't go much past 10psi on a good day...i hope urs turns out better.



It does look nice though!

i'm not a huge fan of the stock turbos. they are good for street driving because it spools so fast but a small t04e could do the trick nicely

Well, two things influenced my decision to go with a rebuild/upgrade on the stock unit. Time and money. I don't have a lot of either right now to spend on this car, which is a toy for my wife and I (she enjoys drag racing also). I didn't want to get into buying a new manifold, turbo, wastegate, and all the plumbing that would be required to get it right.



I didn't think I was getting full boost from the stock unit. It definitely needed a rebuild, so I figured why not upgrade it as well? The guys at Majestic talked like this setup could boost up to 15 psi, which would suit me fine. Hell, I'd settle for an honest 10 psi. We just need to get this car into the 13's this fall. If we find some extra loot, we might go for more next spring.

What other mods did the car have? Downpipe? Cats? Intake?

It was a streetported motor, dp, hiflo cat, apexi n1 dual, wideband 02, s-afc, etc etc...very well built car...the turbo was just wasnt performing, we put the stocker back on for now and it is doing good...majestic i believe is going to fix his turbo..they said they knew what was wrong and could fix it, but wouldnt tell us what it was...

my hiflow turbo was pretty badass.... i do miss it. that thing flowed up to 15psi.... pos stock wastegate!

yah mine too, it was great



mike

Get nitrous.

for the price you can't beat the only thing is the reliability.... they don't like high boost and start puking oil!

You could say that again!!

But the turbo looks great and 15Psi should get you into the 13's with ease with your setup.

how did they upgrade it? is it like porting? im confused.

As near as I can tell, they yanked the stock compressor wheel, stuck on a larger one, and machined the aluminum compressor housing so it would fit. Also did a 10-degree clip on the exhaust side.

mine they put a different compressor housing on and clipped the exhaust side. i think its nice to keep the stock one though cause all the stock stuff fits with it



mike

You mean like the wastegate piping?

http://www.nightracer.com/fcengine_11.jpg



bad pic but you can see that the compressor housing is not the stock one, 3" inlet



mike

Yellow-rific!

I did the Series 5 T-o4E hybrid thing from Majestic. My other mods were two 720 cc secondaries, upgraded Fuel Pump, S-AFC, Profec B, 9.5# flywheel, K&N intake with a Mariah cold air box. Racing Beat Downpipe, presilancer and Apexi N-1 Cat-back.



I do not 1/4 mile - my car is set up for Autocross - BUT I did take it out for a test and tune to see what it would run. I turned a 13.08 running 10 PSI and dont know what I am doing. If your mods are similar and your a drag racer you'll see high 12's with that setup.

Just look at your sig. GET A BOOST CONTROLER!! It will make your car ramp up boost faster and higher. The turbo upgrade is awesome but will not shine until you do a boost controler. I prefer Profec B but there are others. Sell a kidney whatever you have to do just get a boost controler.

Help me to understand this. I thought a boost controller would only let you increase maximum boost. The ones I've looked at just delay the opening of the stock wastegate to a higher pressure.



How does the boost controller affect how quickly the boost comes up?

Anybody?

I am not going to get into a whole debate on the actual workings of the boost controler. I will tell you my observations from my own experiance.



With out a boost controler I would see peak boost at 6K RPM on up WITH the boost controler I would see peak boost at 3,500 RPM and it would stay there until redline.



When you have a boost controler your car will pull harder down low.



You will not regret it. Best money I ever spent and if I could do it over again it would have been my FIRST mod. Period.

i agree!



APEXI AVCR! best money spent on car. Other then buying car itself.

I'm not looking to debate anything, I just want to understand how it works. It is obvious to me that the act of opening or closing the wastegate can affect only the maximum boost level. What other means does a boost controller have to control boost? I would think that how quickly the turbo spools up would be defined by the actual turbine geometry, whcih is something the boost controller would not be able to vary.



For those of you with self-installed boost controllers, what does a boost controller consist of?

I didn't mean it as I do not want to argue with you 1988RedT2.



Everytime this subject comes up an argument brakes out over how they work.



I really dont care how they work other than how it feels when I drive my car. Is it faster with a boost controler? Yes much faster. Thats all that really matters. It makes your boost more constant over a wider RPM range.

Well, you can call me crazy if you like https://www.nopistons.com/forums/pub...1047683785.gif but I'd have a hard time coughing up the hundreds of bucks for a boost controller without having a clue as to how it would help me. And the butt dyno is not a very objective test method. Can anyone shed some light on what means a boost controller uses to control boost besides the wastegate?



I've read several product reviews and some of these controllers perform no better than a ball valve.



http://www.sportcompactcarweb.com/tech/020...boostcontrol08/

Let me see if I can shed a little light on this for you. We all agree that boost controllers work by changing the boost pressure to the turbo acctuator. Now think of it this way, your acctuator is controlled by a spring, and as any other type of metal it weakens over time. on and off boost puts a strain on the sping over time, and it just cannot hold the boost desired or hold the acctuator closed against the boost pressure being fed to it. In some cases a boost controller takes away the boost pressure from the spring, allowing it to work as it should and then meters the boost pressure according to how it is set. If Jims boost controller dropped his spool up that much, I would have to say he has a worn acctuator spring or the boost line was too big for the acctuator (or wastegate of which I am not sure of his setup).



So yes, there is a possibility that a boost controller can lower boost peak levels, but it is becasue the unit is not feeding the same boost pressure against the spring anymore.



Hope this makes sense to you.

Mazdadrifter has a ball valve boost controler. Its for sale if you want it. A ball valve is fine but is a PITA to adjust. I helped him w/ adjusting and could see how a blown engine could very easily happen if you are not quick with your right foot. They are very touchy. The benefit of a electronic one is basically ease of adjustiblity. I can change my boost as easily as I can change the volume on my radio.



I did not want to get into the whole debate on the workings of them because it was not the point of this thread. I have done a ton of research on every part I have put into my car and know what I am talking about.



I prefer real world "butt dyno" over what companies claim.



Fedrex from Teamfc3s had the identical setup as me except bo boost controler my car would clobber him in a race. He was wasting time spooling up I was pulling away.



Higher gears we were even but 1st and 2nd I had the advantage.

i love my blitz sbc-id the limiter function is great.... stops overboosting!

because the stock turbo is only set at 5psi.

a boost controller will not help it spool from 0-5psi any faster then stock.



however with no boost controller. at 5psi the wastegate is fully open. any boost after 5psi is boost creep. and creeping is "slow rising".



your turbo at 5psi. creeping to 10psi. is ALOT slower then a boost controller set at 10psi.

because the stock turbo is only set at 5psi.

a boost controller will not help it spool from 0-5psi any faster then stock.



however with no boost controller. at 5psi the wastegate is fully open. any boost after 5psi is boost creep. and creeping is "slow rising".



your turbo at 5psi. creeping to 10psi. is ALOT slower then a boost controller set at 10psi. [/quote]

Thank you, Scott! That makes a whole lot of sense. I don't know where I got it in my head that the wastegate spring was set for 10 psi. I swear I read it somewhere. I may be mistaken.



Hmm. It seems I need a boost controller...

The ProfecB is the best bang for the buck with EBC's. If you can find a used one on E-Bay then go for it. You'll love it.

Like I said best mod you'll ever do. https://www.nopistons.com/forums/pub...DIR#>/wink.png

Okay. Update time. Car is back together and running with the new turbo. It makes boost just fine, but I didn't dog it too hard tonight. Majestic says to idle the car for 5 minutes without revving it. I did that. Also drove it around a bit. Any other "break in" required for rebuilt turbos?



I'm not crazy. The 1988 Mazda factory service manual describes testing the wastegate by applying 10 psi to the actuator and verifying that it moves. Hence my prior belief that the wastegate didn't come into play until 10 psi.



To settle the issue once and for all, I hooked up an air pump and a pressure gauge to my wastegate actuator today. Sure enough, it starts to move at around 5 psi. Pretty much wide open by 8 or 9 psi.



As much as I find the fancy-schmancy electronic BC's attractive, I suspect I'll go with a cheapie manual boost controller 'cause my budget is spent.