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DIY Turbo Discussion greddy on a 1.8? homebrew kit?

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Old 11-16-2006, 11:47 AM   #21
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SaaaWeeeeet!

Makes me want to order the last couple parts for my turbo setup and get cracking. But no...I need to replenish the coffers from my initial purchases before I can spring for an intercooler and piping and oil lines.

I have 6 305 injectors (from a Supra), so if you find somebody else willing to part with 2 spare injectors, we could work a deal for my 2 extras.

How's your BOV working out?
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Old 11-16-2006, 11:59 AM   #22
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Originally Posted by samnavy View Post
Well, I don't know. I've got the Walbro 190 with the base pressure on my AFPR set as recommended by Begi... I think 48-50psi, so I set 49psi. It idles great.
Well, the idle at 20 ~Hg. should still be 35psi, then the adjustment screw should be set to make it around 50psi at 0~Hg. So just disconnect the vacuum line to the FMU and FPR.

Max rise will be 12:1, or possibly more so you're probably throwing those fuel pressures way up there. Try to tune for 100-110psi at max boost.

I just took a log of my 1.8L injectors at 9.5psi. A/F below 5k, is a bit lean, AFR after 5K is still a bit rich.



If I was running the BEGi FMU I could possibly richen up the initial AFR as I could bump the fuel pressure up to say 55-60psi at 0~Hg. and still cap the max rise to 100psi. I need to send it back to Corky to take a look at (I've been lazy and haven't done it yet)

I'll lower the boost to 8psi and let you see the results.
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Old 11-16-2006, 02:43 PM   #23
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Originally Posted by magnamx-5 View Post
yes i am right once agian. way to go now get a clutch.
Please. Look at the post right before yours..

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Originally Posted by UofACATS View Post
Is the resistance there when you manually open the wastegate?


Much love Mag5, you'll get em next time



Double :gay: (I'm such a dumbass)

Last edited by UofACATS; 11-16-2006 at 03:03 PM.
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Old 11-16-2006, 03:00 PM   #24
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The motor sounded fine and pulled like crazy against the slipping clutch. I'm not sure what it would be like at a steady 11psi with my foot to the floor
Thats sweet. I can't remember if you've done the Spec clutch yet?

I'd guess no, it be insane otherwise
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Old 11-16-2006, 03:03 PM   #25
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Brain, I was unlear earlier. I did adjust the AFPR with the vacuum line off as suggested in the Begi instructions, and then verified that it returned to normal after re-connecting the line. Is that A/F graph from your LC1 software?

What do you think the best way would be (without a dyno) to verify the fuel pressure rise under boost? How would I monitor it while driving?

I'm liking the fact that you're seeing a safe 9.5psi on the 1.8's. I think I would be REALLY happy right now if I could tune for that... might hold off on the installing the bigger MAF and injectors... but still want to buy the injectors and have them on alert status.

Atlanta, the BOV is working great. I'll get a short vid and soundbyte tonight for y'all. It's fairly quiet and not annoying at all. So far, works perfectly... but longevity of the PVC check-valve will be the true test.
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Old 11-16-2006, 03:21 PM   #26
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Atlanta, the BOV is working great. I'll get a short vid and soundbyte tonight for y'all. It's fairly quiet and not annoying at all. So far, works perfectly... but longevity of the PVC check-valve will be the true test.
Try this. Do a WOT run in 2nd gear, when you are into the boost pretty good, try easing back on the throttle while staying in boost. How smooth is it?

When I was VTA my car bucked like a **** when I would do this. Changing it to recirc fixed the problem. However it is possible that my BOV is fucked and not able to hold up under boost.
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Old 11-16-2006, 04:31 PM   #27
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Is that A/F graph from your LC1 software?
yes, some of the best money I've spent.

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What do you think the best way would be (without a dyno) to verify the fuel pressure rise under boost? How would I monitor it while driving?
use about 3-4' of hose off the tee on the pressure gauge. Put the guage under your wiperblade; go boost crazy and see what the max pressure is. Adjust accordly with the bleeder valve. Or if you have an air compressor, set the regulator to the level of boost you'll see, shoot it into the vacuum line of the FMU with the pump in prime mode and monitor the levels and adjust.

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I'm liking the fact that you're seeing a safe 9.5psi on the 1.8's. I think I would be REALLY happy right now if I could tune for that...
It was a lot better with the 305s, however I hate going rich (seeing 10.5:1) with the RX7 AFM after 5k. I'm going to be trying a few things to see what can result in the best. Most likely a little less boost and the 1.8L injectors with the stock AFM. Unless I can get the 305s to idle with the OEM AFM, which I'm pretty sure they will, then that should have good results.
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Old 11-16-2006, 11:27 PM   #28
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Brain, you're the man. I've got plenty of leftover fuel line, so will run it under the wiper so I can see it and shoot for [email protected] assuming I can get a steady 9psi with the new WG actuator.

JayC, yup, it gives one good buck if I come off the throttle at a medium rate. If I let up very slowly, the BOV never opens and it's smooth. If I completely lift, it doesn't buck either. It's minor annoyance now, but I'm getting smoother (gotta learn to drive again!). Recirc will probably happen after the new BOV whoosh sound wears thin.

So, projects in order are:
Replace worn WG actuator w/spare DSM one.
Install fuel gauge line and run gauge under wiper blade and tune for 110psi of fuel at 9.5psi of boost.
Play with MBC to determine best setting
Change clutch
02 clamp
WB (LC1 w/panel meter)

That should get me satisfied for awhile. Sometime before next summer I think we're talking EBC and maybe DIY WI for summer temp safety!
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Old 11-17-2006, 12:03 AM   #29
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i'd tune it for maybe 7-8psi at 100-110psi of fuel max, i really don't like it running at 13.5 AFR at the low-end of the RPMs. Maybe if you go to 60psi at 0~hg. Otherwise not worth the risk if there are any variances in our systems that you can't read yourself without a wideband. Not sure if you have an 02clamp installed as well, without it you may have worse lean tip-in.


I just threw them back on and happened to take a log without changing anythign else in my system. I have since dropped it down to 8psi. I'll be trying a few things out this weekend and I'll let you know my results. But for now play it safe.
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Old 11-17-2006, 02:26 AM   #30
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I need to get a wideband again, then I can tell you guys what AFR's Im seeing. I have used a WB before and I was around 12.5:1 and then it would go to 10.5 :1 at about 5000 and stay there.
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Old 11-17-2006, 02:42 AM   #31
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Originally Posted by samnavy View Post
JayC, yup, it gives one good buck if I come off the throttle at a medium rate. If I let up very slowly, the BOV never opens and it's smooth. If I completely lift, it doesn't buck either. It's minor annoyance now, but I'm getting smoother (gotta learn to drive again!). Recirc will probably happen after the new BOV whoosh sound wears thin.
This was a major problem for me. I'm building the car primarily as an autocross car, not being able to feather the throttle in a slalom is an issue
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Old 11-17-2006, 04:51 PM   #32
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I need to get a wideband again, then I can tell you guys what AFR's Im seeing. I have used a WB before and I was around 12.5:1 and then it would go to 10.5 :1 at about 5000 and stay there.
Exactly what I was seeing with the 305s. I just hate the rich top-end.

here's my 1.8L injectors at 7psi with the OEM AFM at about 100psi of fuel

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Old 11-17-2006, 05:20 PM   #33
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Ah, barely cut off the AFR #s. Squinting, they read 8, 10, 12, etc? *Old glasses* N/M figured it out duh

Braineack, do you plan to work with the 305s or make the 1.8s work as best as possible?

Same with the MAF situation. I'm still on the stock, but was planning on 1.8s + RX-7 MAF. That plot looks much better than #22, although it still seems like the same although better "lean then rich" issue, both switching at ~5K RPM. Seems Mr. Floyd reports similar..

Maybe a byproduct of somewhat limited FMU???
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Old 11-17-2006, 06:16 PM   #34
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Brain, I'm not gonna be able to limit myself to the 7psi without an EBC. The DSM wastegate I think is a 9psi unit, so I'll be in that range. I think by your graphs, that a base pressure of about 55psi, with a rise to 105-110 at about 9.5psi on the 1.8's and stock MAF should get me a damn fine flat curve. I'd rather be a little rich on top than a little lean. I'm all about the 3500-5500 midrange anyways.

When you dyno'd it and saw your 190rwhp, what exactly was your setup... I know you've posted before, but sum up please.
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Old 11-17-2006, 08:05 PM   #35
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9psi, 102psi of fuel, 305cc injectors, RX7 AFM:




9.5psi, 104psi of fuel, 265cc injectors, RX7 AFM:




7.5psi, 97psi of fuel, 265cc injectors, OEM AFM:




What I've been trying to accomplish is getting it leaner towards redline. 9psi and the 305s worked really good, but i would hit 9.x:1 AFRs towards redline. No knock present on any of the above runs.

UofACats, look at the graph again, I couldn't have made reading the AFRs any easier. (Hint, purple numbers)
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Old 11-18-2006, 12:08 PM   #36
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Originally Posted by UofACATS View Post
Ah, barely cut off the AFR #s. Squinting, they read 8, 10, 12, etc? *Old glasses* N/M figured it out duh

Braineack, do you plan to work with the 305s or make the 1.8s work as best as possible?

Same with the MAF situation. I'm still on the stock, but was planning on 1.8s + RX-7 MAF. That plot looks much better than #22, although it still seems like the same although better "lean then rich" issue, both switching at ~5K RPM. Seems Mr. Floyd reports similar..

Maybe a byproduct of somewhat limited FMU???

Yes that is a byproduct of the FMU setup. One my car what I have to do is have the base pressure of the FMU @ 55psi and the rate of gain around 8:1. I run the AFM a little loose too, this gives me the extra fuel I need under 4500rpm where the engine will run lean unless you take steps to avoid that. I get about 12.5:1 or 12:1 AFR's from 3500-4800 rpm or so. However all that fuel added to keep it rich at low rpm makes it pig rich on the topend. I generally see 10.5:1 AFR's up top...which is safe but just a little rich. I just deal with it since there is nothing else I can really do. The reason it gets richer right around 4000-5000rpm is because thats where the stock computer allows the injectors to run at a higher duty % meaning that they stay open longer and supply more fuel to the engine. I have my o2 sensor disconnected on my car so that I dont get a lean tip in, I still get 21mpg so its not all that bad
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Old 11-18-2006, 02:30 PM   #37
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Originally Posted by braineack View Post
look at the graph again, I couldn't have made reading the AFRs any easier. (Hint, purple numbers)
Thanks for the graphs!

I edited after I posted when my brain turned back on and I actually looked at the graphs


Floyd: Those numbers seem a good compromise. Think I'd prefer richer up top opposed to leaner mids. Trying to think what AFR factory turbo cars run. I know it's plenty rich, I'd bet they (any factory turbo car) will hit 10.5 easy so it's not a horrible thing. Just leaving a little power on the table and some smoke out the back.

Higher duty cycle at 4-5K, interesting bit, did not know that.
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Old 11-18-2006, 06:05 PM   #38
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You guys are awesome... with this kind of homework and research/advice already done, my first dyno day should be a snap!

I've got a set of 305's on the way, so I should be able to get plenty of data in an hour. My new properly sized RX7 coupler arrived last week, so I can swap it in in about 2 minutes (hafta swap the filter bracket over).

As a suggestion, since I'll only be able to test one set of injectors on my dyno day, should I keep the 1.8's that are in there, or install the 305's... and of course I'll test with both MAF's regardless.

Brain, I don't see anything wrong with your 9psi/305's/RX7 graph. I'm running the Begi AFPR, so I should be able to tune a little more accurately than the Greddy FMU... whaddya think, install the 305's? I wanna see where I stand at 10psi and I don't think the 1.8's will be enough.
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Old 11-18-2006, 06:18 PM   #39
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I would throw the 305's on there and get a good tune with them since thats the injectors that you are going to want to be using with your setup. No point in tuning with the 1.8 injectors if you plan on taking them out to swap with the 305's anyway.
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