injector placement
 

While there is no question that injector placement can effect performance, as in most designs, there are definitely trade-offs to make. However, adapting the Triumph Speed Triple ITBs to 911 engines, using weber/weber-like manifolds has resulted in a configuration and injector placement that is not significantly different than those used by PMO, TWM/Borla and others. I've used all three (and more) in my EFI/ITB kits and my engine builds.....typically...with excellent results.


https://www.youtube.com/watch?v=K7R3_CXWivk
https://www.youtube.com/channel/UCA2Ea55IQplBIL2F025_P9g?view_as=subscriber

http://forums.pelicanparts.com/uploa...1505666030.jpg
http://forums.pelicanparts.com/uploa...1505666030.jpg
http://forums.pelicanparts.com/uploa...1505666030.jpg
http://forums.pelicanparts.com/uploa...1505666030.jpg

Ignition map
 

Since Clay has blessed us sharing maps on this thread, I thought I'd toss mine out there.
I haven't done much messing around under 1200rpm on timing. I also would like to add more timing around light load from 2500-4000rpm. I want to try to lean out the VE map there and run more timing so that I can see better MPG.
I feel like I can probably run more advance at full throttle too but I want to have a very qualified tuner say the same whilst the car is strapped to a dyno.

I put it in a spreadsheet so as not to leave out the MS and other EMS brands out there that might be following along. Please feel free to tell me where I have screwed up or where i might could add some timing. I have never tuned EFI before this car so I'm fine with learning from others.
http://forums.pelicanparts.com/uploa...1505765112.jpg

Thats good info, thanks for posting. I'm curious though - should we run less advance with ITB than with a plenum? I'm currently 5 deg BTDC at at idle 30 deg at WOT. But that's with CIS plenum. Interesting to see what happens with the ITB.

Below is my ignition map. I based it on an estimation of a stock Motronic ignition map I found in a thread somewhere on this forum. I'm anxious to get to a dyno/tuner that can help me get the ignition tuned more aggressively.

I'm not sure any comparisons can be drawn between my tune and Shaun's above??

http://forums.pelicanparts.com/uploa...1505848988.png

i found this chart of stock 3.2L on 911chips.com which helped me get started too.
http://www.911chips.com/FTign.gif

Pehlen you seem to be pretty advanced at WOT down low, say under 2500RPM compared to above. Would you actually hear ping that low if you went too far or just give up some power?

Posting this has inspired me to go back and look at the info I used to get to this point.

I can't find what I used originally. The charts I thought I used are all throttle % by RPM, not MAP.

Last night I created a new ignition map based on the two maps below (from an old thread on this site) - I'll post a link to the thread .

My first test drive of that had a different feel for sure. I am scheduling some dyno time this week or next.

http://forums.pelicanparts.com/uploa...1505929704.png

http://forums.pelicanparts.com/uploa...1505930032.png

Here is the link to the thread I referenced earlier. I've read it 4 times now and continue to learn.

http://forums.pelicanparts.com/porsche-911-technical-forum/452932-tuning-programmable-engine-management-systems.html

Any of you gents get your 2.7 or 2.8 on the dyno with your setup yet? My twin plug 2.8 with DC65 cam is almost together and I have Clay's system, I'm guessing it will be good for 230-240 at the wheels or 270-280 flywheel. 39mm intake ports with the works. Last similar motor I built similar to this (but with MFI) made about that, but the MFI was a serious pain to get dialed in correctly and was still a touch lean at the top end.

I look forward to seeing the dyno run of this 2.8...........Please post when you have dyno results.....those are some serious numbers.

regards,
al

So I'm nearly done with my ITB install. Only thing missing now is those damn velocity stacks. I'm really having a hard time finding 42mm stacks that fit the triumph throttle bodies. I would like somewhat long stacks, as I'm looking for a little more power in the midrange. Also I really like the look Al has on this pic:

http://forums.pelicanparts.com/uploa...1506371399.jpg

Based on this diagram

http://forums.pelicanparts.com/uploa...1506371399.jpg

I'll need 20'' - 22'' (from intake valve). I'm about to go for some 45mm (inner diam) and make adaptor plates to make them fit the 42mm intake, unless you can point me in another direction?

Found this eBay seller recently, no affiliation.

Velocity Stack Kit for Triumph T955I Throttle Bodies 50mm Long | eBay

Warning: Longish post!!! I got to rambling again...

Spent about 10 hours at the dyno yesterday with a very experienced tuner and made some HUGE changes to the ignition timing map. The end result was MUCH snapper response, more torque and hp over pretty much the entire rev range(talking like 15-20hp increase) and way leaner cruise afr for better mpg. It feels like a completely different motor!

Also, the last car on his dyno before mine was a honda 1.6L with 1000whp. Bloody hell....

My car was pulled onto the dyno with 93 octane fuel and a knock sensor watching over us for protection. We learned some about the AEM EPM that I'm using for cam/crank signal as well.

AEM EPM issues -
We were seeing a big dip in torque around 4700-5100 RPM. Then it would ramp back up again. It looked similar to when you dyno a honda and the vtec cam comes on. Big jump of 15-20 ft/lbs just after 5100rpm.
So we locked the ignition to 23 degrees and did some wot runs while watching the crank pulley with a timing light. The timing is NOT stable. It was jumping around 2-3 degrees in most areas and around 4750-5000 rpm it was retarding quite a bit, around 8-10 degrees judging from the crank pulley marks and my best guess watching with a timing light. That explained the big dip in torque. My tuner mentioned that he had tuned a few other cars with the EPM's (hondas and nissans) and they also had erratic timing. Its too bad because its a terribly convenient way to get cam and crank signal on the flat 6 motor when paired with the adapter that Rasant offers.
We spend the next hour trying to remove noise from the crank duration signal and removing the distributor to inspect for signs of damage or something to explain the erratic timing. Everything looked good so we chalked it up to the EPM not being consistent and perhaps some weird harmonics around 4700-5000rpm.
We did see some improvement after reinstalling the distro and having to re-sync the cam/crank. I had previously had it installed with 0 offset and 0 camsyncadjust. Perhaps it worked better when it had more distance between the missing teeth.

Bottom line - The EPM and adapter are an easier solution but a less accurate one.

So we moved on and worked on WOT and got the mapping as good as we could with a margin of safety against knock. Power was about what you'd expect for mostly stock '83 sc. The only performance mods on my motor are the lighter crank and the slightly higher CR. Cams, heads, headers are stock.

Next up was cruise and light throttle. We ended up setting the lambda target leaner around 14.7 to 15.0 afr here. At first we had lots of lean pops and hesitations but after adding GOBS of timing it smoothed out! We added as much as 19 degrees of additional timing around 3,000 rpm. This resulted in lightening fast throttle response in addition to the much better mpgs. Here are the maps: My original map i previously posted; my new ign map with the added advance; the difference from one to the other. (numbers are rounded to nearest whole number)

http://forums.pelicanparts.com/uploa...1505765112.jpg

http://forums.pelicanparts.com/uploa...1506884686.png

http://forums.pelicanparts.com/uploa...1506884686.png

Regarding my hp numbers... lower than I wanted but I have to remember I didn't do hardly anything to help the performance when i built my engine. I was on a strict budget and just wanted to have the damned thing running again. I wish I had saved some for cams and maybe large port heads but i didn't so thats what I get. We also noticed that Cyl 3 isn't as happy as the others. Less change when we shut that injector off. Something is off there and I might be looking at removing the motor again this winter to learn what it is. 180whp with a torque line flatter than a 2x4!

Not a new phenomena:

AEM EPM SBC/BBC timing drift | AEM

Thank you for a very informative post! I'm still a novice in EFI tuning so others may correct me, but 180whp (aprox 210 crank HP?) is not very good for a Euro spec CR, rebuild and EFI converted 3.0?? Surely, there must be an issue (as you suspect your self). I gained 25HP alone by converting to EFI (running stock dizzy and stock '78 intake runners with common plenum), but then again I have more agressive cams and straight 42mm headers, which may give a synergistic effect.

What is your compression?

my 3.2SS is built on a '78 with large port intakes and has a CR of 9.8:1. Excited to see what the ITB will ad.

The Euro spec '83 with CIS had 204crank hp with CR 9.8:1. Would expect at least 220 from converting to EFI/ITB?

Yes, not what I wanted exactly. But just a couple of clarifications. 9.3 CR is standard for an 83 US spec from what I read. My motor had earlier 8.5:1 pistons when I tore it down so I get confused on what should be stock vs what I had. Second point, the dyno was a Superflow Autodyn which is about 8% lower than a Dynojet I'm told. There is a Dynojet in the next bay and the 8% diff is what my guy says they typically see.
Still I was gunning for 200 wheel and didn't get there. I'll post the dyno plot when he emails it to me this week.

9.8:1 Euro pistons are a good upgrade on an SC.

A friend has a 3.2SS, MFI, twin plug ignition. Compression is 10.3:1 via Wossner pistons. Engine makes 275 hp at the wheels. It's a horse.;)

CIS isn't going to cut it although it can be "worked" via some clever massaging. It is still limited.

IMHO, the later '80-'83 engines don't flow as well with the smaller-stock CIS runners. A '78-'79 is a much more "free" engine. Having owned both examples I prefer the larger runner engine even though Porsche claims both engines make the same horsepower.

Interesting issue you are having, I have zero timing drift with my EPM. Have you tried playing with the pickup delay settings in the wizard? This is specifically there to combat timing drift:

http://forums.pelicanparts.com/uploa...1506961103.jpg

That explains a bunch. You're probably right around 195ish at the wheels on a dynojet, which is all I use as they are so consistent. 195 on a 911 with a 915 gearbox and standard 16" wheels translates to about 220-225 at the flywheel.


Rasant are actually about to produce a much better trigger than the AEM hockey puck for reasons you experienced so you're not alone