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LOW DYNO #S (3.3SS EFI/PMO ITBS EURO HEADERS M&K muffler

Hey guys, I finally got my car to the dyno this week and was very disappointed with the #s. I had a 3.0SC before with a 3.2 intake and motronic EFI that did 214HP back in the day. So I was thinking my new 3.3 SS would do way better then that.

It has good HP and torque up to 4k-4500RPM and then goes flat. The engine was done by EBS racing, see attached build sheet. It originally had 40MM PMO carbs. I was told the build was based around knowing it was going to be using carbs. They chose "Mod S" cam as you can see.

I wanted an efi set up and went with AEM infinity which my guy who tunes loves (he is a Motec dealer and was surprised by how good the AEM is). We used 50MM PMO ITBs, I know that seems large but he says it shouldn't cause what we are seeing on the dyno.

His theory is that the motor is now a hodge podge of random parts that are not working well together. My question is where do I go from here? I have allot of $$ into the PMO/ITB conversion.

Is it a matter of new cams or cam timing? My mechanic says no way of telling w/out getting in there and seeing whats really in there. He doesn't believe anything any other "builders" say they put into engines.

Or is time to just part out and get a 3.6 993 motor? I was hoping my 3.3SS was going to make 240-270 HP. It ended up at 170, less then a US 3.0SC engine. VERY UPSET! Any help would be great.

By the way, it feels "seat of the pants" fast, I love the car but just was expecting more power.


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Last edited by nippy; 01-14-2018 at 08:34 AM..
Old 01-14-2018, 08:28 AM
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a few engine bay pics






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Last edited by nippy; 01-14-2018 at 07:24 PM..
Old 01-14-2018, 08:35 AM
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Eliminate intake/ exhaust issues by trying one pull on the Dyno wo exhaust and air filters/trumpets?
Old 01-14-2018, 10:10 AM
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Something is very wrong!! I have 260 in my stock 3.2 with ITBs of similar size.
Do you have a dyno graph to post with AFR?

Does it run smoothly?

I would do 6 pulls each with one injector disconnected to se if all cylinders are there.

If it just dies after 4000ish, maybe there is signal problems, noise on the crank pickup or something. I would trouble shoot thees things.
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Last edited by safe; 01-14-2018 at 03:43 PM..
Old 01-14-2018, 03:37 PM
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170hp at the hubs? Or crank? Or wheels?
Old 01-14-2018, 05:16 PM
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Quote:
Originally Posted by kjchristopher View Post
170hp at the hubs? Or crank? Or wheels?
First pull was like 140 with no tuning, then 172 once air fuell was straightened out. It feels allot faster than 170 by seat of the pants and the drop off isnt really noticeable. I just hate to think its that low on power. It drives fine.

I think the torque is from my old sc, he was mixing old maps and new maps to show comparison from my first car to this one.


From my tuner

I am finishing up today, all the AEM setting checked see photos, many number were slightly off, so I fix it. The power is still down, from 4000-5500 power is flat; this is the typical issues when the engine parts are mixed matched. No more tuning can fix at this point. It did gain you 40-45hp and ft/lbs. There is an orange paint mark on the crank pulley, I am not sure if AEM installer put it there or engine builder out it, thatís the wrong place for TDC. It is the 5degrees before TDC. So I reset the AEM correctly.

I donít really know what EBS Mod S cam is, nor who grind the cam, the cam makes all the difference.

Also the PMO is almost too big, 50mm ; but it would not cause what we are seeing on the Dyno. It is really a combination of all the sums of parts; exhaust too.

I suggest driving it and have some fun, and maybe change internals later.

This is not the first time I see this exactly problem, and it is always the combination of mis-match parts. Unfortunately, there is a ton of mis-information out there.

Btw, I end up getting transfer to senior AEM engineer, because all the lower guys canít answer my questions I had; the truth is, most tech guys donít know anything, they are just reading the instruction manual.

I want to do a little more cold start tuning in the morning, and probably pickup afternoon. Once car heat up, canít do cold tuning.

Also not sure if your AEM guy told you , that you donít have idle control on your car. So it makes cold start a little more difficult. Also the idle not as stable with weather and temperature changes.

Last edited by nippy; 01-14-2018 at 07:26 PM..
Old 01-14-2018, 05:28 PM
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wow
hope you will find the problem...

Last edited by frankoporsche; 01-14-2018 at 07:26 PM..
Old 01-14-2018, 06:53 PM
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Your engine should be making more power than that. My 3.2 ss with 120/104 camshafts but carrera intake makes 224 rwhp.
Old 01-14-2018, 08:14 PM
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Wow....
I would check cam timing so they are in the right ballpark and even both sides. But I think you have an EFI problem or ignition related.

If it still with the tuner tell hem to do the 6 pulls if he hasn't. If those 6 pulls isn't the same there is an issue with that one cylinder.

TB-size is not an issue, maybe not ideal for low load running, but its not there you have problems...

Call up ebs and have a chat with them.
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Last edited by safe; 01-14-2018 at 11:29 PM..
Old 01-14-2018, 11:20 PM
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Old 01-15-2018, 04:50 AM
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A Mod_S cam should have a peak torque in the range of 5200-5500 in a 3.2. The peak torque you show at 3800 is in the ball park of what I would expect for displacement. However, its way off in terms of placement.

The large ITBs (too large to me) would affect low speed response and tip-in due to swept area of the throttle plate. It will not limit overall flow at higher rpm. Have the manifolds been matched to the heads? Even smaller manifold ports relative to the heads should not limit this much. And some step is a good thing with a standard lobe center Mod_S cam to control reversion relative to the MAP signal for EFI.

I will assume that the heads are stock 3.2 - meaning not modified. The stock port should be good for well north of 300HP flow requirements.

How do you trigger the EFI signal? Cam sensor, crank sensor or flywheel sensor? Has your tuner verified that the timing is constant all the way through the RPM band and there is no latency?

Has he verified trigger noise to make sure there is no interference in the EFI system at high rpm. I have seen this more than once.

I see that your car is using COP setup for spark. Are the dwell settings correct for the coils? Is the voltage supply and ground connections appropriate for the coils? At high rpm if there is voltage drop due to current draw the coils will delay charging with causes drift in your ignition timing. Make sure the wires are large enough to not current limit or add line resistance at full load at full duty cycle. It acts like a retarded ignition. Given the abrupt drop in torque at 4krpm I would look further into this.

I can not tell from the pics exactly what type of coils these are. Are they 4 wire smart coils or 3 wire driven by the ECU? If direct drive by the ECU look for FET overheating indicating too much current draw. You may have to go to external ignitor or different COP setup to solve the problem. I prefer logic level "smart coils" for these type of installations. Anything to take the load away from the ECU.

My process to check the engine side to rule out mechanical problems would be to (not necessarily in this order):
Verify cam timing.
Verify there are no exhaust restrictions.
Verify there are no intake restrictions
Verify that your linkage is setup correctly and you get WOT
verify compression and leakdown.

Following this I would look closer at the EFI wiring and setup. Did you datalog the runs? This will tell you a lot about what is happening on the EFI side. The car has the sensors and feedback. Use them.
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Old 01-15-2018, 05:57 AM
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Very sorry to hear about the issues. I would first perform a compression test to see just what you’re cranking. It should, I would think, be around 150. Your cam is fine, I drove a 2.5ss using a dc80 cam (twin plugged and higher cpr though) and it was still pretty streetable and that is a much crazier cam and in a tiny motor. If the cranking compression is no good then check the cam timing and make sure both sets of coil on plugs are firing. your torque is ok so the heads are flowing, but peak torque is being realized too low for that cam.

What port sizes are you running? important. PMO 50s are fine but considering you are not twin plugging with higher compression I would have used 46 or even 40.

The AEM hockey puck trigger is known to dance timing around a tiny bit as well hence why rasant are developing the external trigger and crank wheel. The AEM sensor would not be the smoking gun though.

I think your tuner is flat wrong that this is a mismatch of a lot of things. There is something obviously awry here causing this substantial issue.
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Last edited by lvporschepilot; 01-15-2018 at 06:40 AM..
Old 01-15-2018, 05:59 AM
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[QUOTE=jpnovak;9886166


I can not tell from the pics exactly what type of coils these are. Are they 4 wire smart coils or 3 wire driven by the ECU? If direct drive by the ECU look for FET overheating indicating too much current draw.

[/QUOTE]


They look like 4 wire COPs. AEM Infinity powers the coils via an external power source which for 6 coils should be on its own 30amp relay. The 4 wire smart coil system has a wire going back to the AEM brain indicating successful fire but I do not know the extent of the information sent back to the brain. This is good info though, thanks for posting re dwell and retard etc, very handy.
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Old 01-15-2018, 06:45 AM
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If the AEM powers coils from an external source then there should just be a logic level trigger signal. This is the best situation as there is effectively no current from the AEM ECU to the coil. Just a switching signal to turn on the internal FET on the coil. It is no different than any other logic level coil on plug trigger.

From experience the COPs are sensitive to their electrical settings. Power then too long (dwell) and they can overheat, and change resistance on the windings. Is this a Rasant system? If so, settings should be good. However, did the tuner make any changes in an attempt to get it working? Hard to say with limited information.

Also, is this configured 6 coil sequential or 3 coil wasted spark?
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Old 01-15-2018, 07:02 AM
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The AEM system can be set for 6 coil sequential. I, nor do Rasant to my knowledge, use a logic level sensor.

I really like using the separate relay boxes that a pre-wired, makes it very easy and they work great, clean etc.

https://www.ebay.com/itm/Universal-Waterproof-Fuse-Box-Relay-Panel-distribution-Cooper-Bussmann-Off-Road-/222791026568?_trksid=p2385738.m4383.l4275.c10
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Old 01-15-2018, 07:12 AM
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Quote:
Originally Posted by jpnovak View Post
If the AEM powers coils from an external source then there should just be a logic level trigger signal. This is the best situation as there is effectively no current from the AEM ECU to the coil. Just a switching signal to turn on the internal FET on the coil. It is no different than any other logic level coil on plug trigger.
Unless you mix the power earth with the logi earth or like I did got the power and logic wrong du to an internet-schema...
Then you get lots of signal noice and very little power.
Old 01-15-2018, 07:30 AM
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Unless you mix the power earth with the logi earth or like I did got the power and logic wrong du to an internet-schema...
Then you get lots of signal noice and very little power.
That would create a very low voltage to the coils, yes, but I would think they would just stop firing altogether once there was not enough voltage to jump the gap at high cylinder pressures.
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Old 01-15-2018, 07:41 AM
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These guys saying the motor is made of "mismatched" parts are full of it. Your problem here is one of the following, or all three: ITB, tune, FI.
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Old 01-15-2018, 07:44 AM
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Port size? What is this motor built on? Did I miss it somewhere? Some SCs had 34mm ports. Any port matching with the manifolds?

What exhaust system? Headers? What size?

I am not seeing AF numbers on the dyno sheets either.
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Old 01-15-2018, 12:13 PM
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Be sure you AEM guy knows EXACTLY what he is doing. I am not saying he doesn't. But, we had a "fully tuned" 3.0 on PMO with AEM Infinity at the shop last year. It didn't feel right at all. We sent it over to a known amazing AEM tuner a few miles away. They found 40HP in it.... Just sayin...

Post info on the port size, exhaust design/size, AFR and timing curve. The ITB's are too big, but should not be causing low peak HP numbers.
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Old 01-15-2018, 09:22 PM
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