A 3.4 DOHC Build then... F40 Turbo (Page 54/57)
3.1 88FieroGT FEB 26, 12:07 PM
Doesn't look like you have a whole lot of room but a recirculating blow off valve would help with losing boost during shifting. Are you using a maf or just map sensor? Your coding and tuning abilities are very inspiring lol. I'm hoping to have my build up and going before spring. Picked up a 97 monte carlo for obd2 donor harness and 4t65e transmission. Going to be using dhp tuner which seems to have its limits.

[This message has been edited by 3.1 88FieroGT (edited 02-26-2016).]

Fierobsessed FEB 26, 08:16 PM
MAP only.

Thanks for the compliment, I'm going to release the code and the highly modified definition that has all the patches, and custom stuff when I find a nice way to do so, and I get the definition buttered up for a public release.

Recirculative BOV's are said to be for MAF applications where you don't want to vent already measured air. But even then, it's kind of BS. The compressed air between the turbo and throttle blade still gets measured as it reverts back through the MAF. So even then, it's not really doing as it's advertised.

Either way, when the throttle blade shuts, almost all of the driving energy from the exhaust stops driving the turbine, and the compressor is still pumping a whole lot of air through the BOV, no matter the type. So the turbo has all the reason in the world to slow down as quickly as possible. Keeping the throttle blade wide open, allows the turbo to pump the air into the engine still, and a large amount of exhaust continues to drive the turbine, so the turbo slows down very gracefully. And as soon as the fuel comes back on the boost is already mostly present.

I'm currently working on the flywheel, so far so good , I've got the material machined to shape, I just have a ton of holes to drill, tap and counterbore. I took a bunch of pics, looking forward to seeing how it comes out.
Fierobsessed MAR 05, 08:37 PM
It's been a fun week. Loads of work was done on the flywheel, So here goes!

Raw materials


I drew a 12" circle on it just to give me an idea where I needed to trim it down


I had to cut the flywheel down to a rough circle, since my lathe can only tolerate a roughly 12.5" diameter stock before I have to pull the gap bed out. Trusty sawsall did the work. It was a lot of cutting!


I needed a hole in the center to even chuck the stock, so I had to break out the hole saw.



Then, I started chipping away at the OD and the ID, working the center out to 5" and the OD down to 11.600" and then surface cuts on both sides.


The disc blank is done!


Next, I had to work on the hub section. I intended this flywheel to be two pieces as it would have been a colossal piece of billet. I could have done that, but it would have been more work really.
Same treatment as before, trim down the outside bore the ID, surface both sides. This time I was able to chuck it from the outside, 7" is right on the edge of what my 3 jaw could take with the external jaws.


Then I did the disc side cuts.


Then the engine side cuts, the two pieces fit together nicely!


With the billet blanks done being machined, It was time to take the take them over to the milling machine and start putting a whole lot of holes in them. The rotary table was as much of an indispensable part of the production as the lathe.


I started my taps with the milling machine right after drilling the holes, so I know they were straight and true, and located exactly in the right place. I then finished off the holes with the hand tap. Much lower risk.



Lotsa holes!


For the off the shelf Fidanza friction plate to bolt to the disc, I had to counterbore all the holes for the length of the screws.


I then made 6 stand-offs for the starter ring, easy work on the lathe again


I figured out what my plate depth needed to be. I wound up having the friction disc be 0.040" above the surface of the flywheel. This way I can use the increased clamp pressure plates with my clutchnet disc.


Bolted on the stand-offs.


Cut a little off the edge off the standoffs till I had them down to 11.092" and then slipped the ring gear over the standoffs.


A little welding


Bolt it all together, and that's pretty much it!



Also, I got my Clutchnet "95-08 Ford Ranger" clutch disc.


It's all coming together... I still have to do some pressure plate soul searching. I need to find a more positive release design, and a ton+ of clamping force. Hopefully I can find a good answer to that issue.
sardonyx247 MAR 08, 12:26 AM

quote
Originally posted by Fierobsessed:

Looking at my data logs from my quarter mile run, I learned a lot about my driving, and the car, and how the two of us can work together to shave a butt-load of time off the ET.

The breakdown looks like this:
0.0s I launched, no boost at all at and at 100% throttle the moment the wheels started turning
1.6s Boost hits 10 PSI in first gear, I'll consider this the point where the turbo is "Spooled" I was actually pushing 16 PSI solidly when in boost.
2.2s I release the throttle and shift. This also happens to coincide exactly with my 60' time.
2.7s I'm back at full throttle, so my 1-2 shift was 0.5 seconds to complete.
3.1s Turbo is back to 10+ psi. that's 0.4s after the shift was complete.
4.8s I release the throttle and shift
5.4s Full throttle, 2-3 shift was 0.6 seconds long.
5.7s Turbo is back to 10+ psi. that's 0.3s after the shift was complete.
8.7s Shift begins
9.3s Shift complete 3-4 was 0.6s
9.5s Boost is back at 10+ .2 seconds after the shift.
12.85 at 117.

It was a good run, but It really pointed out where improvements could be made.
If I consider anything that is below 10 PSI, to be turbo dead time, then...
I was out of boost for 4.1 seconds of the quarter. In boost for 8.7.
Total time at zero throttle? 1.6 seconds.

Realizing these issues, I wrote some new code, ran a wire between the ECM and the cruise control servo to tap into the brake/clutch input, and added two new features:
No lift to shift, and staging control.
No lift in my code works as follows. When the throttle is at 90%+ and the clutch pedal is not fully released, (basically anytime its pressed at all) a lower rev limiter is set based on current speed. It sets a rev limiter at the predicted RPM that the next gear will shift into.

Staging control is simply a rev limiter that is present when the vehicle speed is below a specified MPH. I have it set for 5 MPH and 3200 RPM.
So I can floor it and the engine will bounce off the rev limiter at 3200. Then as I release the clutch and the car takes off, it will exceed the 5 MPH and allow the rev limiter to jump to 7000.

In testing, I found that although the code works exactly as intended, the driver (me) has to re-learn how to drive stick, as everything I have ever known to be right says to remove the right foot from throttle when using the clutch, and so far, in two attempts, I have failed.

Best part, I found that the turbo remains in boost for a whopping 2 whole seconds when No Lift To Shift kicks in. That's astoundingly long. The engine at high RPM with the throttle blade open, pumps plenty of air to keep the turbo more than happy. Its when you close the throttle blade for a half a second at 16 PSI, you will only have 0-2 PSI when the throttle blade opens fully again. The Blow off valve doesn't do anything to keep the turbo spooled, it merely keeps the turbo from suffering a massive air reversion through the compressor (compressor stall/surge) which can cause catastrophic damage to the turbo.

I'm still struggling with the whole right foot thing, but I can't wait to try it out again when I find a safe place to practice.

Shortening the shift times themselves will have to be a function of a new, lower inertia clutch disc, and I'll have to be more aggressive myself.



You know I came up with the EXACT same idea for launch/staging control at the last track day. and to be done exactly the same way.
RPM limit under certain MPH.

Looking at your last set of pics, you prob spend more time with your lathe than you do you wife

Can't wait to see this next track day Show everyone what a 60deg can do!!!!!
Will MAR 09, 09:21 PM

quote
Originally posted by sardonyx247:

You know I came up with the EXACT same idea for launch/staging control at the last track day. and to be done exactly the same way.
RPM limit under certain MPH.



FYI, DMSLink was doing shift-no-lift since at least the early 2000's (and I'm sure others did it before that).
sardonyx247 MAR 10, 04:45 AM

quote
Originally posted by Will:


FYI, DMSLink was doing shift-no-lift since at least the early 2000's (and I'm sure others did it before that).



No I was thinking of launch control, and I know others have done it, I was just thinking about how to do it on a Fiero ECM with the knowledge that I have, not saying I am the first, but saying I thought of how to do it myself, with no knowledge of how it is done.
3.1 88FieroGT MAR 20, 03:58 PM
Bump for update
ericjon262 AUG 09, 08:35 PM
any updates?
Fierobsessed AUG 15, 08:34 PM
None to speak of. Its 110 degrees outside and the car runs too hot in the summer to drive. The old clutch and flywheel are still in the car, and it still slips. The synchros on the transmission are being funky too. So I will have a bit of a go through at some point to address all these issues. But in the meantime, it is parked just mainly due to the heat.

I am working on a 3800 SC build for my other car in the meantime, and that's coming out great so far. But I've been quiet here while I mess around with that.
Joseph Upson AUG 23, 02:46 PM

quote
Originally posted by Fierobsessed:
None to speak of. Its 110 degrees outside and the car runs too hot in the summer to drive. The old clutch and flywheel are still in the car, and it still slips. The synchros on the transmission are being funky too. So I will have a bit of a go through at some point to address all these issues. But in the meantime, it is parked just mainly due to the heat.

I am working on a 3800 SC build for my other car in the meantime, and that's coming out great so far. But I've been quiet here while I mess around with that.



If you have the means or a local shop near by, have your pressure plate clamping pressure checked as that may be all you need to address to resolve the slip issue. I had mine modified to 2300 lbs as you may recall from a ~1900 lb baseline.

As for the synchro issue, if it's not the common struggle associated with first and second gear on cold start up I'd be concerned. Before my first F40 started to come apart I had trouble shifting into 6th gear without a scrape under light load for about a month. It was a strange, new, seemingly minor issue until it wasn't. Hope that's not the case because if it is that means you probably have to back off the boost. As for your cooling issue, if you can't keep temps around 210-215 deg F under normal driving in 110 deg heat I'd be suspicious of a possible foreign object somewhere on the engine end of the coolant passages.

Is it possible you have a coolant loop somewhere in the system like what's found on the 2.8L where coolant bypasses the engine headed toward the heater core until the thermostat opens?


Just looked at some of your pics earlier in the thread, I see you have some recirculating coolant nipples on the water pump inlet housing. Is it possible recirculating hot coolant is the culprit? The 3900 has a similar arrangement where some coolant coming directly from the cylinder head coolant outlet is recirculated directly to the pump inlet.

[This message has been edited by Joseph Upson (edited 08-23-2016).]