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First step toward turbo |
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CFoss 
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Joined: 13 February 2007 Location: Canada Status: Offline Points: 580 |
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 Posted: 14 December 2009 at 11:34am |
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I got my turbo on the weekend btw. It is in very good condition, end play is minimal, wheels look good. I'm disassembling it to clean it and check it out and midify it so it can be clocked.
So far so good. I think I'm going to get the 20G upgrade to improve the turbo compressor characteristic and order an external wastegate for lower boost setting (Stock is 14lb or so), plus a large size wastegate will help with backpressure issues if the turbine is a bit on the small side. So, for $500 I'll have a water cooled correctly sized street turbo. Not bad.
Next, I'm looking at at least 24lb injectors, which will be ok to about 200 hp at .60bsfc, 85% duty cycle, 45psi (fairly conservative). They're going to be more than the 19lbers, but I need them if I start making more power. Better to do it right once I think.
Chay |
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86 SE 3.4
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Romeo
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Joined: 16 November 2008 Location: Canada Status: Offline Points: 3033 |
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Posted: 14 December 2009 at 1:33pm |
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Have you considered using a divorced downpipe for it, by the way? It dumps the excess pressure to atmosphere instead of into the exhaust system, so you don't flood the exhaust system and sap power. Not sure if it would count as legal though, as the Turbo gets really loud at peak boost.
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Never shift into reverse without a back-up plan.
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CFoss
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Joined: 13 February 2007 Location: Canada Status: Offline Points: 580 |
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Posted: 14 December 2009 at 2:05pm |
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By it, you mean the wastegate?
Yes, I have thought about it, but I don't know if I need to.
My plan is to try a 3" exhaust without a muffler and see how loud it is. It should not have significant back pressure with this type of system, so plumbing the wastegate back into the exhaust won't be a big deal performance wise. If it does get too loud I'll have to muffle it and see how performance is affected. I don't really like LOUD cars. I just bid on a set of 2002 LT1 28# injectors, wish me good luck!
Chay |
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86 SE 3.4
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Romeo
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Posted: 14 December 2009 at 2:09pm |
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No, you're going to have a wastegate regardless, if you didn't, your Turbo would kill itself. But most wastegates vent into the exhaust system, which kills some power off. A divorced downpipe means the wastegate vents to atmosphere, leaving the exhaust unnaffected. I remember some local shop dynoing a Supra to see if it'd make any difference, and they recorded a 29HP increase using a divorced downpipe (Mind you, that was with a large turbo, and larger engine).
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Never shift into reverse without a back-up plan.
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CFoss
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Posted: 14 December 2009 at 2:12pm |
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I've also been toying with the idea of building a proper boost controller with pid feedback from a second MAP sensor and some type of actuator on the internal/external wastegate. I'm not sure the internal will be able to handle the flow and there might be boost creep...all to be sorted out in the wash.
For the controller I need a pwm controlled actuator...any ideas out there? The egrs and cruise modules I've seen use vaccuum for the mechanical force so they wouldn't work with boost. Any ideas on something that would work?
Chay |
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86 SE 3.4
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CFoss
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Posted: 14 December 2009 at 2:20pm |
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I get that I need a wastegate...No worries...I was vague on the language there.
There are lots of choices. I suspect the best gains on 'divorced' wastegate exits are on marginal original exhaust systems.
It's a balance of plumbing complexity vs performance gain. I think the main obstacle to flow in my system will be peak turbine flow, therfore a large wastegate makes a lot of sense. With a 3" system with very little flow restriction I don't think a seperate exhaust will be merritted.
Chay |
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86 SE 3.4
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Romeo
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Posted: 14 December 2009 at 2:25pm |
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The Supra was running a 3" |
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Never shift into reverse without a back-up plan.
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CFoss
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Posted: 14 December 2009 at 3:37pm |
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It the first car I've ever turbo'd so I'm open to all this stuff. I think it's a good discussion.
The supra was also probably running a CAT and a muffler, which can be high restriction devices, so I can understand the seperate path. What turbo was the Supra running? At what boost level? I'm boosting to such pathetic levels in comparasin to most turbo guys that backpressure is pretty weak. If a guy is running a t4E-50 at 20psi, and 6500rpm, yeah that a lot of flow. We can use the same compressor, but run 5,6,8 psi without a lot of work on the 60V6, not really a lot of flow, especially with out weak top ends.
Anyway, it's trial and error at this point. The turbine side is less quantitative, so it's hard to get a feel for performance changes, and then there is the street vs 1/4 mile vs top speed tradeoffs to consider (IE: My engine won't spend a lot of time at 6000rpm WOT).
Chay |
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86 SE 3.4
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Patrick
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Joined: 19 April 2008 Location: Vancouver Status: Offline Points: 5 |
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Posted: 14 December 2009 at 4:55pm |
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Something about these two comments in the same post just doesn't jive.
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CFoss
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Posted: 15 December 2009 at 9:30am |
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It could be LOUD, then I'll take steps to fix it. It probably will be too loud, but I have to try it. I think the turbo will suck up a bunch of sound energy.
Also, I found a lead on the boost controller...you can get a typhoon cyclone solenoid for pretty cheap. I'm going to try it hooked up to my own controller. It should work up to the limitations of the wastegate. Basically, I'll match the characteristic of the 40mm wastegate electronically so they won't fight each other, plus I'll slow it down so it doesn't oscillate.
Also, I think I'll run a 40mm external wastegate and synchronize the internal wastegste control (Via pressure). From what I've read the internal won't limit boost until like 10psi. The internal wategate is sized thinking the standard application boost is higher than this. Because I want to boost lower, I need additional wastegatage (Ok, I just made up that word). The internal wastegate is twin 20mm diameter holes, which when their area is added to the 40mm wastegate, will act a little smaller than a 50mm wastegate. It's a place to start.
Chay |
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86 SE 3.4
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Romeo
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Posted: 15 December 2009 at 2:14pm |
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Well, I think the unmuffled 3" might be extremely loud, as Patrick stated, but with the Turbos solely, the exhaust will damped than noise in a non-divorced (Still-married? lol) set-up. As to the Supra, it was running 24psi, so yes, chances are the effect would be much less on your set-up.
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Never shift into reverse without a back-up plan.
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CFoss
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Posted: 16 December 2009 at 11:07pm |
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I'm going to try to post a couple of pics...turbo:
 Hey it worked! I've split the turbo up to check it out. The above is a 9.6^2 exhaust turbine, and HR center section.  This is the comp housing side. It's a 16G6, not to be confused with either a big or small 16G. I still don't know if I want to spend the $200 to upgrade to a 20G wheel and TD06 compressor housing...I probably will though. On the exhaust turbine I ground off a tiny pin, and now both sections are 360deg clockable. i ordered up a 60mm external wastegate, so the original actuator is toast, and the internal wastegate will get welded shut. Chay |
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86 SE 3.4
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Romeo
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Posted: 17 December 2009 at 1:58pm |
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That a perfect-sized snail. Small enough you don't have to wait a couple weeks for it to spool up (And therefore better torque), large enough to produce some good power figures.
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Never shift into reverse without a back-up plan.
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CFoss
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Posted: 17 December 2009 at 2:15pm |
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I hope you are right. From my calcs the compressor will be a bit small but I think the turbine should be right on the money. I didn't want to leave the spool too long, cause the intake system runs out of flow up top anyway. My idea was the car will be quicker if I maximize the low end potential rather than try to extend the high end torque. It will still extend the useable rpm range, but not to the extent that a big top end turbo would. Plus I like to get sucked back into the seat, but ease off at 120k...hopefully with the Honda in the rearview I'm starting to think I'm going to try the 16G6 compressor and log the intake air temps as I start boosting above 4 psi. If the intake air gets too hot too quick I'll know I need the bigger compressor for increased efficiency. If not, I saved $250. I'll just run it rich until I find out.
Chay |
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86 SE 3.4
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Capt Fiero
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Posted: 22 December 2009 at 8:06am |
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Chay I am no expert when it comes to Turbo motors, however the 3.4 in your Fiero has more than enough punch off idle, if you can light up the tires now in first gear, then I would try to tweak that turbo to spool much later, like in the 2500rpm-3500rpm range. Once you clear 1st gear all your shifts will take place at a much higher rpm and the rpm drop will only go down to 3000rpms at the lowest. Congrats on getting it this far, I am sure no matter what happens you are going to have a blast with it. |
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Capt Fiero
88 Fiero GT 5spd V6 Eight Fifty Seven GT V8 5spd. |
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CFoss
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Posted: 22 December 2009 at 9:45am |
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You're right about the spool range. I expect it to spool right around 2500. Any lower could be a waste.
It may make boost threshold earlier, but I don't expect it to max boost until maybe 3000. This is all specuation, and has primarily to do with the turbine sizing, which is supposed to be similar to a .7ish a/r (Most run a .63T3, so I'm optimistic).
Ideally, I'd like full boost level by 3k, to take the useable rpm range from about 2.5k to about 6k. Max hp will still be around 5200-5500, but will be higher than stock of course. I did win the 24/28# injectors from a LT1 (There are either 24# or 28# depending on your fuel pressure setting). I should have plenty of fuel. And I got a 1227730 and harness, plus a 60mm wastegate cause I think I'll be bypassing quite a bit at initial low boost settings and I don't wan't creep, now to get a bov and figure out the $58 programming (Syclone/Typhoon)....should take me at least another 2 days eh?
Chay |
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86 SE 3.4
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CFoss
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Posted: 22 December 2009 at 9:57am |
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As a note to your original question, as long as you have good traction, the later you leave the boost the slower the car will be in the quarter. If you boost later you may have a higher final speed, but it will be slower overall. Given that I'll be on the street/autocross, I'm looking for more low end. The Fiero manifold flows ok at between 2.5k and 5.5k, then it dies...this is common knowledge. So, if you bring the boost on late, it will feel like you are extending the torque way up into the high rpms, but you will miss the oportunity to build higer torque earlier.
From Displacement = VT+1/2AT^2, the faster you get going earlier, the further you go. Or, the other way to look at it is getting going faster earlier raises your average speed more than having a high top end speed for a shorter period of time (And therefore reduces your time for a given distance). This is critical on a short duration course like a 1/8 or 1/4 mile (Or god forbid the street). It's pretty wordy, hope that makes sense. I just have to get the power down once I start making it, but that's the fun part. The car already goes fast enough for me. It doensn't get going nearly fast enough though. (From that video...Rotary? I want STUMP PULLING torque). So, I've thought about it a bit.
Chay |
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86 SE 3.4
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Capt Fiero
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Posted: 02 January 2010 at 11:18pm |
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Any updates?
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Capt Fiero
88 Fiero GT 5spd V6 Eight Fifty Seven GT V8 5spd. |
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CFoss
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Posted: 14 January 2010 at 4:11pm |
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Yeah. I bought a 60mm wastegate and LT1 24/28# injectors. The wastegate was a ebay special, but when I recieved it I was pleasantly surprised at the quality. I opened it up to find a very good thick silicone diaphram and solid spring action. The only problem was it was supposed to actuate in the range of 4-8psi, but I found it cracked at 10psi and was full open at 15psi. So, I cut the spring and now without preload it cracks at 3psi and is full open at 7psi, and can be adjusted to crack up to 10psi if wanted. So I'm happy with that result.
The LT1 injectors are shorter than the fiero injectors. Also, the top to keeper groove was onger than on the fiero. So, I made a new groove in the injectors which is closer to the top, then the length under the keeper is right on. It still has lots of length to seal up top in the fuel rail...Needless to say I'll be pressure testing thoroughly. Also, I found this on Pennocks by accident:  I have a spare middle intake so I think I'll try to make one. I may end up needing a bigger turbo after though!!!!! It's supposed to make a big difference in the rpm range, especially for a 3.4. Chay |
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86 SE 3.4
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CFoss
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Posted: 14 January 2010 at 10:34pm |
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Had some fun tonight...
           I need to add a full tubular section to accomodate the throttle bodies, but not bad overall. Pretty simple job so far. Chay |
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86 SE 3.4
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. But yes, I suppose for the smaller turbo (I presume) it might be an acceptable trade so you don't have to deal with the extreme noise.
CFoss wrote: