Just another damned project thread, 914-6 3.2 conversion in GT dress-up Options

[DNHunt]

SDS compensates for altitude. I believe it takes a pressure at start up and that value is used in the fuel calculation. It also has a mixture knob that enriches and leans the whole fuel table. So a tune for sea level should work at altitude. The problem is the value taken at start up is used until the car is started again. For most of us this isn't a problem but, when changes in altitude are really large this could be a problem or at least a nuisance.

I had problems with this at WCR 10 in Tahoe. When you increase altitude there is less O2 so the required fuel is less. My concern was that it seemed the correction the ECU used each time I started the car was going the wrong way and I had to enrich the fuel table instead of leaning it as I went up the mountain. Until I realized what was going on I was real concerned. The SDS mixture knob was a handy work around but there was an underlying problem. I suspect it was a firmware issue and SDS would require the computer be sent in to them. I'm sure it would have been an easy fix for them, I just decided to go different direction.

I am running Megasquirt now and one of the reasons is that I can run 2 pressure sensors. The first one samples the manifold pressure to for engine load and the second constantly samples atmospheric pressure to continually adjust for altitude.

[ConeDodger]

Dave,
Thanks for taking time to comment. I know you are busy with Betsy these days. I hope she is doing well.

I will be running an EM-4 F ECU. This is of course the 4 cylinder - crankfired set up. What SDS set up were you running?

So, if I understand you correctly, I should be alright the second time I start it at a given altitude?

[r_towle]

So, if you are going out on a short trip...50 miles or so, you would be best advised by SDS to pull over three times and turn off the motor, then start it again to reset the ECU for a proper mixture?

I suspect most of the world does not have your specific regional elevation changes.....so that may be true.

If I used SDS, I would never have to deal with that issue...its all within 1000 feet difference around here...unless I decide to drive up a mountain...but then I can stop and start I suppose.

Sounds like a PITA....put a big red sign on the rearview mirror to remind you to do that once in a while...dang.

Rich

[DNHunt]

First of all Betsy is doing great. She ran the Chicago marathon 2 weeks ago and we did the 3 day Walk for the Cure (60 miles in 3 days). She tougher than me.

Rob, I had the same model but, it's the version of the firmware I think you need to look at. When the computer boots it'll give the version #. I think mine was 16.

It would be a pain in the but to have to manually adjust the mixture. I have to believe that what I found was a bug and I assume it has been fixed in later versions.

Dave

[ConeDodger]

First of all Betsy is doing great. She ran the Chicago marathon 2 weeks ago and we did the 3 day Walk for the Cure (60 miles in 3 days). She tougher than me.

Rob, I had the same model but, it's the version of the firmware I think you need to look at. When the computer boots it'll give the version #. I think mine was 16.

It would be a pain in the but to have to manually adjust the mixture. I have to believe that what I found was a bug and I assume it has been fixed in later versions.

Dave

Thanks Dave! Glad to hear Betsy is doing well! (IMG:style_emoticons/default/aktion035.gif) Mine is Version 17...

[Mike Bellis]

Will you stick it in the car already and drive it? Geez... OK fine, I'll drive it (IMG:style_emoticons/default/biggrin.gif)

[ConeDodger]

Will you stick it in the car already and drive it? Geez... OK fine, I'll drive it (IMG:style_emoticons/default/biggrin.gif)

/

It goes to Original Customs on Sunday for the install... Talk to Mark if you want to help with that... (IMG:style_emoticons/default/biggrin.gif)

[wndsrfr]

So, if you are going out on a short trip...50 miles or so, you would be best advised by SDS to pull over three times and turn off the motor, then start it again to reset the ECU for a proper mixture?

I suspect most of the world does not have your specific regional elevation changes.....so that may be true.

If I used SDS, I would never have to deal with that issue...its all within 1000 feet difference around here...unless I decide to drive up a mountain...but then I can stop and start I suppose.

Sounds like a PITA....put a big red sign on the rearview mirror to remind you to do that once in a while...dang.

Rich

Hey Gang....I posted this thread to Ross Farnham at Racetech/SDS to get his comments on how the system works with altitude changes. Here's his information:

"The engine does not care what the baro is to any great degree when
starting within the normal realm of say sea level to 5000 feet MSL if
the start and ET values are set to some mean level as we recommend in
the manual. We apply no baro correction for altitude because the engine
only cares about MAP when running and this is an absolute sensor we use
so assuming the MAP values are essentially linear as we recommend, the
engine will lean automatically with altitude increase and richen when
going down. The fact that we have many hundreds of systems flying in
aircraft and UAVs to over 25,000 feet over the last 17 years shows that
the system works well over a very wide range of altitudes. Our system
does not "learn" a new map like OEM systems today or do anything
different when you turn power off and on again.

Generally the start and ET values have no effect on anything when the ET
is over about 130F as no enrichment is required above that point.

If closed loop is used in cruise conditions, the ECU automatically keeps
the AFR around 14.7 to 1 regardless of the open loop values.
With regards to merging TP and MAP, the first thing I'd say is, it is
usually inappropriate to use a hot cam and ITBs on a street engine
simply because there is no vacuum as soon as the throttle plates are
cracked open so there is no vacuum signal for the MAP sensor to measure
and send to the ECU- garbage in = garbage out. Also, even at idle, the
vacuum is so low you are only using half of the sensor resolution. We
can use TP for idle fueling only with warm cams to help stabilize it and
MAP above the closed throttle TP value but with high overlap cams, idle
vacuum actually increases at slightly high rpms and this inverts the
logical fueling that "normally cammed" engines have and need. We see
many people disregard our advice on this and end up with poor
driveability. You don't see OEMs use ITBs and high overlap fixed cams
(usually VVT with mild cam timing down low). They also use MAF which is
not affected by idle vacuum values. 3D systems would have an advantage
here over a 2D system but MAF is is much better idea than MAP when using
hot cams and ITBs and I believe any programmable system able to use MAF
will be superior in this application. MAF is messy though with ITBs as
the ITB inlets need to be merged into an airtight airbox with MAF sensor
attached to the front.

You can switch SDS to TP but then you have no altitude compensation and
TP setups are usually harder to tune because people don't grasp the
concepts well.
Well executed plenum style manifolds and single throttle bodies
generally work much better on street engines. ITBs have their place on
race engine where revs are high, throttles are generally half to wide
open and low end cruise and driveability are not very important factors.
The ECUs simply respond to their programming- they don't know any
better if it is good or bad for the most part although we have an auto
enrich function if a WB is fitted to help save the engine from really
bad programming."

So, my understanding is: If you're on MAP sensing, it compensates automatically--they use these systems on aircraft for heavens sake! If you're on TP sensing but in "Closed Loop" mode, the system will strive for 14.7:1 AFR regardless of altitude, which covers any cruising type of street driving. If you're racing at an altitude markedly different from where you developed the fueling values, you'll need to lean or enrich your whole table--which really only takes 5 minutes once you've done the homework. My 2316 on SDS with TP sensing with Jake's 9560 cam works wonderfully for me in street driving and DE's at VIR & Summit Point--elevation changes less than 1500 feet total.

[ConeDodger]

Mine has closed loop O2 sensing. Not so sure though about Ross saying that people 'disregard their advice'. I told him I was running ITB's when I ordered and he offered no such advice. He just took my order.
Mark seems pretty sure everything will be fine. At any rate. I did 600 miles of driving between Friday evening and just now, delivering a car - a hydraulic lift and other such driving including an autocross. I am tired. It's in the capable Original Customs hands now... (IMG:style_emoticons/default/biggrin.gif)

[ConeDodger]

Well let the fun begin! Dwight Mitchell Motor out (Jim, get a car ready (IMG:style_emoticons/default/smile.gif) ) Now for the new motor...

Oh hell! It was upright on my camera screen. I will fix this later. Gotta go to work. Fixed!

[FourBlades]

That is great, Rob.

You are almost there.

John

[rick 918-S]

(IMG:style_emoticons/default/popcorn[1].gif) (IMG:style_emoticons/default/aktion035.gif) Hey Rob, pm me your address. Your in Reno now right?

[Jake Raby]

SDS has always been against ITBs on their systems.. However NONE of the folks at SDS have built or tuned a TIV engine. I have north of 60 under my belt using their system to include the 2.8 liter, 220HP MassIVe engine that I drove to the shop today with temps in the low 30s as it resides in my Double Cab with an SDS based EFI system. That engine is tuned by TP because it has no MAP signal.
I have ALWAYS found the TIV engine to tune EASIER with ITBs than a common plenum WHEN THE MAP sensing was set up optimally.

In fact both times that I have had SDS tuning issues was when I used a common plenum. I tuned my engine in the double cab with 30 minutes on my chassis dyno and two trips to/from my house @ 45 miles each. I haven't touched it in 3,000 miles and I just started daily driving in a few months ago.

220HP and 28 MPG in a heavy assed truck with a lead foot driver- I must have done something right.

[ConeDodger]

Oh cool! The admin fairy fixed my sideways picture! Don't you just love them admin fairies? (IMG:style_emoticons/default/cheer.gif)

I'm not too worried about tuning... I mean, for one thing, SDS seems to be referring to ITB and IR system as radical racing setups. This one isn't.

I think Mark and I are going to use a real world dyno first. The Mayacamas mountain range via the Oakville Grade from Sonoma to Napa and back should do the trick. (IMG:style_emoticons/default/driving.gif)

[ConeDodger]

This is pretty cool! We decided the best place to put the ECU and the controller for the O2 sensor was under the passenger seat. Kind of ala 911 Carrera with the DME relay under the drivers seat. We did this for a couple reasons. 1: the SDS ECU is a hideous gold anodized finish. It's just wrong and it reminds me of why we need to attack Canada some day... Better yet, we will send them decorators. (IMG:style_emoticons/default/poke.gif) 2: the ECU needs a cool dry place to live. At least in my 914, under the passenger seat is a nice cool dry place... 3: Did I mention it is ugly? (IMG:style_emoticons/default/barf.gif)

So Mark decides that it would be best to have a weather proof plug on the firewall that the engine room harness plugs in to. This allows me to unplug the motor and drop it without disconnecting all of the EFI. Pretty neat Original Custom idea huh?

Damn! another sideways pic! Where is that admin fairy? (IMG:style_emoticons/default/cheer.gif)
(IMG:http://www.914world.com/bbs2/uploads_offsite/fc04.deviantart.net-419-1320193536.1.gif) Ta-Da!

[ConeDodger]

Since this engine will be crank fired, we will be using a coil pack to distribute spark. Mark decided that the best place for this would be just aft of the relay board in the engine room. I might try and talk him into fabricating something to brace that free corner of the coil pack though... (IMG:style_emoticons/default/biggrin.gif) I will probably get another demeaning look but hey! (IMG:style_emoticons/default/smile.gif)

[ConeDodger]

(IMG:style_emoticons/default/popcorn[1].gif) (IMG:style_emoticons/default/aktion035.gif) Hey Rob, pm me your address. Your in Reno now right?

Will do Rick! Still trying to get that graduate thesis book back to me? (IMG:style_emoticons/default/biggrin.gif)

[ConeDodger]

That is great, Rob.

You are almost there.

John

Thanks John! We are going to get it tuned and autocross it one last time for the year then it will spend some more time with Mark at Original Customs getting flares welded on. With more power comes the need for more tire! (IMG:style_emoticons/default/biggrin.gif)

[McMark]

Getting closer... (IMG:style_emoticons/default/first.gif)

We are using AN lines from the engine up to the remote oil filter. We're going with AN-6 lines (just kidding Jake!). Actually it's AN-8. I couldn't find the AN-8 fittings to mate up with Rob's Mocal filter console, so I just bought some weld on fittings and pulled out the ol' TIG welder. Done!



The next issue was that the full flow oil pump cover outlet port is too close to the engine mount brackets. I've tried all sorts of things to get it to work, but always had problems getting the fittings tight. I decided to stop trying to make a poor layout work and modified the cover as you can see. This effectively moves the fitting out another 1/2" and then everything clears fine. There's plenty of room behind the fan housing, I could have gone another 1/2" easily, but this works.





The vacuum signal is running through a pretty unique setup (AFAIK). Rob and I wanted to use a stock AAR to provide a nice warm up, fast idle. So we are running this common plenum for the vacuum. The front four ports go to each intake runner, below the throttle plate. The smaller port on the left goes to the MAP sensor, and the tube on the right goes to the AAR. This lets the plenum serve double duty by combining the vacuum signal for the MAP and giving even distribution of the AAR airflow. It seemed to work just dandy on the stand, and we'll see how it work during tuning. The ITBs have smaller vacuum ports available if we decide that this setup isn't working and need to switch things up.



And finally, a shot of the oil filter mount, with oil lines attached, and you can see the wiring harness poking through just above the filter. It's going to be a little tight in there, but there should be just enough room. At the next filter change we'll swap to a longer 914/6 filter so that it will be easier to grab onto for filter changes.



Tomorrow, a couple more mods in the engine bay, and if everything goes well, we'll get the 2432 lifted into place. (IMG:style_emoticons/default/boldblue.gif)

[McMark]

Oh, and I hate the red/blue fittings. But it's all I can get locally, and we don't have time to mail order everything. (IMG:style_emoticons/default/dry.gif)