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Hi everyone, as the title says, I have a ridiculously low hp 20b turbo, hoping to be able to get some suggestions and possible answers.
Spec of the car
- Street ported 20b with Solid dowel pin and enforced studs and Power seals
- HKS T51R SPL with 1.0 a/r
- Turbosmart 60mm Wastegate
- Adaptronic M6000 ECU
- Microtech X6 + Bosch coils
- Electric Water Pump
- 3.5" exhaust all the way with a racing beat 3.5" muffler
- Walbro 460lph
- 850cc Primary & 1680cc Secondary
Car is only running 14psi, full boost by 3,800rpm. It was running lean past 6,000 rpm and very high EGT. Already tried to richen to ~ 10 AFR.
Mustang Dyno only showing 222whp (DID NOT MANAGE TO SNAP A PHOTO)
Tuner (also the Mechanic who built this motor) suggested I get another bigger turbo with larger a/r as they were suspecting too much backpressure.
Decided to check out another dyno in town to confirm the previous dyno was not faulty or uncalibrated.
Did 2 power run and came out pretty much the same.
Dynojet - 174whp and 179whp.
Comments from this tuner were:
- Bad tune
- Agreed on turbo being too small BUT should still put down 500whp easily
- There was a 20b with the same setup running HKS T51R KAI w 1.0 a/r doing 600whp
- He won't touch adaptronic as he had a bad experience with it (something like his computer had a different version with the ECU and it overwritten his customer's entire map?)
- Suggested I change my ECU to Link or Haltech.
Tuner #1 is a rotary specialist and had done many successful projects and high hp rotary so I am sure he knows what he is doing. Maybe missing on some simple honest mistake?
Though I must add, he totally does not care about drivability (which I seek) and just focus on achieving figures. I've asked why my car jerks so much and all he could say is "owh because it's ported". I know this is not the case though.
Tuner #2 is a full-time tuner and he tunes all sorts of engines including rotary.
Did some cruising and he was already dissing at how poorly the map was tuned on drivability. So, he is already biased from there.
We did 2 power runs to around 6,000 ~ 7,000 RPM to be safe as I have told him about my issue of the lean condition past 6,000 RPM.
I am in a big dilemma as there are only 2 tuners who could do rotary and both are suggesting me different things.
Tuner #1 Upgrade Turbo
Tuner #2 Change ECU
I strongly doubt the turbo is the reason that the car is not putting down the power. Don't want to be spending another few thousand bucks for a new set of turbo and still face the same issue.
I also feel it will be wasted by changing my ECU as the M6000 is very capable.
Hence I am here to seek further advice. Could a poorly tuned map be the sole reason for the car to be doing this little power?
I am not even targeting crazy high hp. More than happy if it can make 500whp but definitely not 179 and 222!!
since you mention AFR is good but EGT is high, verifying the timing would be a good thing to look at.
pretty sure the T51 is ok for more than 225hp, but checking exhaust backpressure would be a decent idea too, post turbo might even be a good place to start (and easier)
if its not those two, you start with the basics, does the throttle open all the way? do the spark plugs fire? are there boost leaks?
i switched map sensors and didn't retune the map once, so i had a 139rwhp dyno sheet for a 20B :P so it could also be the map....
There is something seriously wrong there. Is there a catalyst in the exhaust? Could be blocked.
Check base timing and confirm all ignition channels are firing when they should. If the wiring to the pump is good that fuel combo should be able to keep up easily, especially at that power level, even if it's mainly generating heat and noise.
You should easily be at 500hp even stock 20b with no turbo can crank out over 220 hp. With your set up right now you should be making 500 hp without breaking a sweat really....... Ryan heinrich can remote tune the car and he works on adapatronics.
i would check:
coils
turbo "see if there is any damage"
boost leaks
ecu map
check fuel pump wiring
Tuning for max power isn't the magic its made out to be, honestly. Either tuner should be able to get more out of that easily with your setup, and very, very conservative timing. This means the problem is almost certainly in the mechanical setup, and should be pretty easy to find and rectify.
Off the top of my head things I've encountered causing situations like this in the past:
Rags left in intercooler pipes.
Super restrictive mufflers, or mufflers installed backwards, if they have a complicated flow path
Throttle cable / DBW setup incorrectly so the throttle is never fully opening.
Fuel system issues, loss of pressure as things rev up.
Even with stock injectors you'd be able to make more power than that before they were out of flow, but I'm assuming you've got bigger injectors fitted?
Make sure the exhaust system is well sealed, so the wideband o2 reading you're getting is actually valid, leaks before the o2 sensor can actually draw oxygen in and make the reading appear leaner than things actually are.
I mean, this is assuming the engine is fundamentally healthy. If the compression was low enough to be the problem I think you'd find it nigh on impossible to start.
IMO, Racing beat canister is tad better than stocker for exhaust flow.
At that turbo size and that much exhaust volume (50% more for stock like 13b RB cat back at simple math), you're having a serious constipation.
Good starting point would be to install a different cat back.
1. Check timing on all six spark plugs (front leading/trailing, middle leading/trailing, and rear leading/trailing), use a paint pen to add marks to the crank pulley. The new marks don't need to be perfect, but you can use a piece of string or wire to wrap around the pulley so you're not just eye-balling the 120 degrees (1/3 of the total circumference) and 240 degrees (2/3 of the total circumference) marks around the pulley.
2. Lock the ignition timing (or set the map to all the same number if the ECU doesn't have a lock feature) and use a timing light (like for setting old-school distributor ignitions) to confirm ignition timing at the pulley matches the ECU's calculated timing values at both low and high RPM, because if the CAS wires are flipped backwards the timing will be wrong at high RPM. I forget whether it goes advanced or retarded, but it will be more than 10 degrees wrong if the CAS wires are backwards. The ECU will say the timing is flat but the timing light will show it advancing or retarding on the crank pulley. You can end up with a similar problem if your ECU and ignition amplifier settings aren't matched, it will be way off at high RPM.
3. I agree with the suggestion above to check for restrictions like a rag in the intercooler or charge pipes or intake manifold.
4. If the dyno's O2 sensor is accurate, there's a good chance the engine is running richer than the dyno indicated 10.0 AFR, although this only happens above 4000 RPM and the torque is too low at all RPM. If you've still got access to the dyno, I would always start with partial throttle pulls before full throttle, to clean up the fuel map at light load first (so you can get a feel for what the higher load cells need to look like before actually putting that much load on the engine). Also it's nice to make sure all systems are working at low power levels before running the engine hard.
5. Have you ruled out clutch slip? It doesn't really sound like clutch slip to me, but a good way to check is gently roll into the throttle in low gears and then in high gears. The clutch is more likely to slip in high gears where the engine has less mechanical advantage over the wheels. When the clutch slips the engine speed goes up but the tire speed stays flat. With dyno numbers so low I think you would smell the clutch burning if it was slipping that much.
6. I agree the drivability sounds bad, it shouldn't hesitate or sound 'jerky' when the driver rolls into the throttle after shifting gears. That doesn't explain the low power, but it could be another sign that the entire map needs a lot more work.
Good luck and please post back when you find the problem.
Last edited by scotty305; Apr 24, 2022 at 02:20 AM.
You are running some seriously old school injectors. Not sure if it's the whole problem but you really need good injectors, like ID injectors. I know those 1680's have been proven to be problematic and those are 80's technology.
I would also check fundamentals - plug wires on right, coils wired up properly, timing properly zeroed and set.
I think the engine, turbo, and exhaust are fine. You have something wrong with the fundamentals.
You are running some seriously old school injectors. Not sure if it's the whole problem but you really need good injectors, like ID injectors. I know those 1680's have been proven to be problematic and those are 80's technology.
I would also check fundamentals - plug wires on right, coils wired up properly, timing properly zeroed and set.
I think the engine, turbo, and exhaust are fine. You have something wrong with the fundamentals.
Dale
Yeap the injectors upgrade are in plan.
Currently still running the stock 850cc, and bosch indy blue 1680cc
Pressure test for boost leaks, check for exhaust leaks, confirm all basic mechanical stuff (as was pointed out, base timing is correct).
Post the datalogs from the ECU, there should be a file for each run.
Post the map from the ECU if possible.
Post the datalogs from the dyno (ask the shop, they should have them). On a dynojet it's the run file.
As has been pointed out, WOT tuning isn't actually that complicated. There's only so many combinations of spark timing, boost, and AFR. Getting it to start, idle, accelerate and drive consistently and safely in different ambient conditions is much harder than a glory run on a dyno.
My money is on a basic mechanical flaw(s) such as a boost leak major exhaust restriction.
Reason we now suspect it's the crank sensor is because it had happened to another mechanic before. ECU will shows everything is working as the sensor was giving the wrong info to the ecu. He had a 13b not making power and egt went nuts and lean.
In fact i had this similar issue with my 13b street port gt35r.
Not making power more than 330whp. Then thought it was the backpressure and got rid the cat and ran straight pipe, still had the same power range.
this 20b build is using the same crank sensor from my 13b. So it got to be it.
Are you talking offset angle retarded or regularly missing trigger counts so retarded by virtue of not seeing enough teeth? Reluctor or hall sensor? Has some scoped the signal?
Ridiculously low hp on Turbo 20b
