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Here are some pictures of the actual modified throttle bodies. Some details are not visible as .001" matter in this case.
Inlet side isometric view. Plate at 30 deg. Notice upstream top contour rework, front lip taper, half-shaft, countersunk screws, and polishing after CNC milling.
Inlet view. Plate at 30 deg. Notice increased flow gaps at top and bottom contours near plate edges.
Outlet view. Plate at 30 deg. Notice increased flow gaps at top and bottom contours near plate edges.
Outlet side isometric view. Plate at 30 deg. Notice downstream bottom contour rework, , half-shaft, flush screws, and polishing after CNC milling.
Manta, Does your modification also help reduce the throttle lag upon deceleration? I have had cases where at WOT from a start the rear tires start to spin causing the rear end to start moving sideways and although there is inertia in the drivetrain which causes the tires to continue spinning when lifting off the throttle part of the problem is the engine doesn't immediately quit generating power either which I am not sure if it is due to the ECU or throttle body. Does your throttle body cause the auto transmission to downshift without the 1/2 second delay when going quickly into WOT? Have you tried it on a Z06? I have the mamo PTB and BMS filter on a Z06 and am please with the improvement, both accelerating and decelerating , but there is room for much more improvement. Does your design also improve the air laminar flow cross section at the mass air sensor and perhaps that's another reason for better throttle response?
After careful experimentation on a totally stock Z51, I have found that if I experience a slight degree of throttle lag, increasing the declination of my right foot from 28.75 degrees from vertical to 36.44 degrees produces an extremely noticeable increase in both throttle response, and acceleration.
After careful experimentation on a totally stock Z51, I have found that if I experience a slight degree of throttle lag, increasing the declination of my right foot from 28.75 degrees from vertical to 36.44 degrees produces an extremely noticeable increase in both throttle response, and acceleration.
If you still have an extra throttle body left, I would love the opportunity to try it out and give you some good feedback on it. My '16 Stingray, Z51, has TSP Long tube headers, high flow cats, and performance tuned by PCM of NC. I am running right at 500hp at the crank, but I am sure the throttle body needs some mod to it. Let me know, your throttle body may be the answer I have been looking for.
Manta, Does your modification also help reduce the throttle lag upon deceleration? I have had cases where at WOT from a start the rear tires start to spin causing the rear end to start moving sideways and although there is inertia in the drivetrain which causes the tires to continue spinning when lifting off the throttle part of the problem is the engine doesn't immediately quit generating power either which I am not sure if it is due to the ECU or throttle body. Does your throttle body cause the auto transmission to downshift without the 1/2 second delay when going quickly into WOT? Have you tried it on a Z06? I have the mamo PTB and BMS filter on a Z06 and am please with the improvement, both accelerating and decelerating , but there is room for much more improvement. Does your design also improve the air laminar flow cross section at the mass air sensor and perhaps that's another reason for better throttle response?
The short answer is, I don't know. I can only tell you that when you lift your foot off the throttle, the throttle plate doesn't go back from 90 deg (WOT) down to the idle angle (say 5 deg) instantly. There may be some ECM intervention so the throttle plate can come back (close) progressively to avoid sudden engine braking/stall.
No, I haven't tried it on a Z06, but I'll do that soon. In fact, I'm planing to test it in all configurations; naturally aspirated and supercharged, with A6, A8, and M7. Stay tuned, results will be posted here by members trying them and myself.
This design does not change anything near the MAF sensor, although improved air intakes should work nicely in conjunction with this throttle body.
Lastly, there is a noticeable, and more importantly, measurable improvement in how the engine delivers power at part throttle and how it transitions to higher power demand.
Last edited by Mike@SolerEngr; 02-26-2019 at 03:06 PM.
Reason: Added signature
If you still have an extra throttle body left, I would love the opportunity to try it out and give you some good feedback on it. My '16 Stingray, Z51, has TSP Long tube headers, high flow cats, and performance tuned by PCM of NC. I am running right at 500hp at the crank, but I am sure the throttle body needs some mod to it. Let me know, your throttle body may be the answer I have been looking for.
Thank you for your interest CorvetteOJ. Please check your PM inbox.
Last edited by Mike@SolerEngr; 02-26-2019 at 03:06 PM.
Reason: Added signature
This thread was deleted for about a week, but it is finally back on. I'm the OP, now under username Mike@SolerEngr (used to be Manta-C7). I'm now a supporting vendor as well, although I'm not selling parts yet. We are still trying to get them tested in several configurations and have had some progress in that regard, but still need a couple members to help please see thread: “ C7 Throttle Body Mod, Free, Need Feedback for Design ”.
Last edited by Mike@SolerEngr; 02-26-2019 at 03:07 PM.
Reason: Added signature
When Mike first posted this I reached out to him for more information and he was gracious enough to offer me one of his modded TB's to try.
I'm fortunate to own 2-2016 Z06's. One is an M7 and the other is an A8. The A8 has never been an issue with an off idle throttle lag or stumble, but the totally stock M7 has. So for the sake of conversation I will be commenting on the M7 and the issues that I have had. Originally I noticed the throttle lag/stumble when the car was being unloaded off the transporter. You could hear it clearly. Driving it, the car was perfect except when you would first hit the throttle off of idle. It sounded like it couldn't clear it's throat. It reminded me of the good old pre EFI days when you needed to adjust the carb and timing. Yeah I'm that friggin' old!!! Also when the active rev match was engaged and you would downshift at a relatively low RPM, it would sound like it backfired through the exhaust. No problem at higher RPM's. This is the best I can describe my experience.
Fast forward I did install a popular vendors ported TB from my other Z06 to see if it helped. It did not, but then again I believe most of the ported TB's that are sold are mainly to get a slight HP increase, not cure the lag issue. If it works for some then great, but it didn't work for me. Mike's work is strictly directed to that problem and isn't hyped as any HP increase.
My results after installing one of Mike's prototypes on my M7 has made a huge improvement. It threw no codes and idles perfectly. My throttle lag off idle is honestly about 90% gone from what it was. The car is so much more driveable off of idle. It is a night and day difference. He's definitely on to something here. As far as the original rev match issue, it's not nearly as bad. It is hardly noticeable but it is slightly there when downshifting in the lower RPM range. Given time and more miles, maybe the ECM needs to learn a bit more to be even better. I know Mike is still tinkering with his design and getting it fine tuned before he wants to offer it to the public. I also believe if Mike can't make it 100% perfect then it won't be produced, but for any of you guys with the throttle lag issue with your M7's especially, and I know there are many, this is the real deal and definitely worth following.
A buddy of mine told me about this thread. Sorry but I read a little bit of it and lol'd quite a bit! The truth of this situation is you're looking in the wrong place to fix this "problem". These GM throttle bodies can and do move as fast or faster than your foot. I say faster because they can literally go full throttle AHEAD of your foot movement.
My buddy has a '16 C7 Z51. He said his car has done this throttle/pedal lag thing since he got it. He drove over and we logged it. I ALWAYS log the relationship between pedal and throttle, many "tuners" don't. If you don't log these two parameters, you won't have any idea of what's going on. Pedal/throttle relationship is one of the most basic tuning/driveability aspects, it literally determines how the engine feels when your foot moves. (Side note... For those that wish for the days of cable throttles, electric throttles can do everything a cable can, and many things a cable CAN'T. Throttle by wire is one of the best things to happen to engine management.)
So no surprise, the throttle mapping in the stock ECM calibrations lags behind pedal movement. This is done for many reasons- better traction, longer driveline life, lower emissions and of course passenger comfort. His C7 did have quite the lag though, I took screen shots of when he jabbed the pedal quickly and the engine almost didn't even react. I could see plain as day the throttle mapping was WAY behind the pedal, it should be obvious in these pictures. I had him pull over, I looked at his tune and changed a few things. Loaded the tune and in the first 2 minutes of driving he could tell it was fixed. The lag was COMPLETELY GONE. I could see it in the log, throttle plate movement was following pedal movement very closely. One tune, 5 minutes, fixed. The funniest part? He said he was going to have to "relearn" how to blip the throttle on downshifts (M7, not using rev-match) because the throttle response was so much quicker and higher.
My advice? Find a reputable tuner and have them fix it for you. It's 100% "fixable" in the tune, it's something any decent "tuner" should know how to do. Changing the throttle body, modifying the throttle body or using an aftermarket throttle body are all NOT fixes for this issue. They will NOT make the lag go away. The lag is built into the engine calibrations.
Here are the screen shots. (Sorry I didn't put the cursor at the actual spots, it should still be super apparent even without seeing the values though. It's really as simple as this- before tune- Blue over Yellow, after tune- Yellow over Blue. lol.) First 3 shots are of the stock calibrations. Blue trace is the pedal position, Yellow trace is the throttle position. Clearly you can see the throttle is lagging well behind the pedal and isn't going even half as high percentage wise...
These are the after tune shots. As you can see, the throttle is opening quicker and in several cases, higher than pedal percentage. In the zoomed in shot you can see the throttle plate actually moved FASTER than the pedal movement....
BTW I just looked at your pictures. You better peen those screws before somebody's engine eats an entire throttle plate and kills someone by revving to the moon.
I have to say you're opening yourself up for some insane liabilities here OP. You've compromised the strength of that shaft and changed the screws, along with having them shorter and with less threads holding them in. And like I said, they don't look like they're peened on the back side. Or how about the increased chance of one of those plates sticking WOT because you've had the gears apart? That's some serious lawsuit potential there, and serious personal injury that can be blamed on you too. You really want to open yourself up to that? Just sayin.
gmtech16450yz, I’d argue that neither of us is looking at the wrong place to fix the problem. I’d rather say that we are taking different approaches, each w/ their corresponding advantages and disadvantages.
Tuning or electronically controlling the throttle plate/blade takes advantage of moving the blade “faster” or “ahead of the foot” to sweep the geometry of the throttle body (TB) in order to increase airflow. What this is doing is simulating a greater pedal travel than the driver is requesting. Many of us have had that type of solution and it does make a difference, but one cannot help but notice that although the throttle responds faster, it does so by following the same path imposed by the geometry of the TB. In other words, it cannot escape the shape of the OEM curve (green) and there is nothing a tune can do about that. Therefore, if the car used to; stumble, hesitate, make abrupt changes of acceleration, etc., it will still do so after the tune only “faster” and in a more abrupt manner. One can certainly move quicker through the issue and pretend it doesn’t exist, but the reality is different, and drivers can and will notice it.
The OEM was designed w/ three very distinct regions, a straight from 0 to 25 degrees, another straight 30-70 deg, then a last curved region after 70 deg (not shown) which is not of importance in this discussion.
The 0 to 25 deg region provides about 1.2 g/s of air per degree of blade travel, while the 30-70 deg region provides about 10 g/s of air per degree. There is a knee (transition) in between those two regimes of the curve. When you transition from one region to another you are changing the airflow rates almost a whole order of magnitude (10X). This is the case described by many drivers trying to pass another car or climbing a hill at 1.2 g/s-deg (not enough) then having to go to 10 g/s-deg (too much) and being at risk of a collision w/ the car in front on the other lane. I’d argue that this is what is dangerous, even more so if enhanced by a tune. Not only dangerous but a persistent nuisance on everyday driving.
On the other hand, the design proposed here takes care of the problem by removing the real/physical barrier to throttle response, that is the geometry of the body itself. The plot (red) speaks for itself. The blade finds an increasingly wider air gap relative to the body earlier in the travel regardless of tune/pedal mapping. The airflow/power at part throttle has been redistributed where needed with a smother transition in between regimes. The driver always knows what the car is going to do, and that predictability makes it safer. The knee of the curve is also wider, and the changes are not abrupt. More importantly, the stumble and the hesitation are eliminated, not swept through with the hope it’s not going to be there. A tune cannot do this.
About the screws and shaft safety concerns:
Fist of all I’d like to reassure you, and more importantly members w/ a genuine interest for this modification, that the main contributors to this design are engineers w/ great academic and empirical backgrounds, also with decades of experience in the fields of aerospace, mechanical, electro-mechanical, design, and materials. I can also tell you that this is not the first butterfly valve we have worked on, neither it is the most critical one.
The screws have been changed to precipitation hardenable stainless steel with 3-4 X picth of engagement (they would fracture under the head rather than stripping the threads), secured at the proper torque value with high temperature aerospace grade thread locking compound, and they are peened as well.
The half-shaft modification has been properly evaluated; metallurgical, static, dynamic, and deflection. In summary; the factor of safety for the half-shaft is greater than 7 (conservatively) with infinite load/life cycles. The weakest point of the assembly happens to be the blade, which is common (for all that matter) to both, the OEM and this design, the factor of safety for the blade is greater than 3. Results follow.
5. Shaft Microstructure. Units in 1/1000 inch. Steel, through hardened and tempered to 100 ksi ultimate strength.
Note: At the risk of giving merit to your speculation, you should know that the ECM will immediately enter limp mode before the car accelerates “to the moon”. In any case we are confident in our design and are able to defend it with data, theoretical and empirical. I have personally tested this design for several months now, members are testing it too. We’ll find out soon enough, stay tuned.
It is also good to remember that half-shaft modifications have been out there for quite a long time and that in that same time period, we have heard in the news about unintended acceleration issues related to software (tune), yes, those have been insane liabilities.
Lastly, if you purchase one of our throttle bodies, you should be able to properly evaluate it and post facts about it. Further speculation will only cloud this thread for the rest of us. You can start a different thread where we can expand on your subject. I’ll try to participate, although I cannot spend much time putting out fires that don’t exist. I’ll do my best based on the merits of your comments, specially if you find more things to “LOL” about.
Last edited by Mike@SolerEngr; 05-22-2019 at 04:48 PM.
Reason: Added signature
Hahaha. You're a funny guy! Leave it to a Corvette guy to over analyze the cr@p out of something that's been common knowledge for years. You know guys have been porting the "bump" out of throttle bodies for a couple decades don't you? It has it's pros and cons. Erratic idle and off idle control is the biggest downside. The "bumps" or ramps that the plate follows as it moves from the closed position is to better modulate the airflow. Chop those out and of course you increase airflow in the first part of plate travel. The reality is though that you don't want the airflow to immediately increase when you open the throttle, that just creates havoc to all the transient fueling and airflow models. Why don't you go one step further though, just make the throttle body an on-off switch? That would really help your sluggish acceleration!
Speaking of transient fueling and airflow models, do you also know that it's common knowledge that IF you modify the throttle body flow that you NEED to change those values in the engine calibrations? Or are you one of those guys that thinks you don't have to tune for things like this? This modification should NOT be done without proper tuning, just like adding headers, different intakes or most any other engine mod. Your ECM (not EMC) will not know what the airflow is at those throttle openings you've modified. It will be using values that are not accurate, and it's calculations for everything from torque control to fueling and ignition timing will be affected. (That's a fact btw.)
- Over analyzing? I thought the "compromised" shaft strength and the shorter screw engagement needed analysis, and so did you.
- Yes, I know porting has been around for decades and w/o tune. But you were concerned w/ that, despite proving satisfactory for so long.
- Erratic idle and off idle are not there, ask the people testing it, they'll tell you.
- I have no problem w/ the bumps, the problem is the smooth ellipsoidal contour adjacent to it. Please read the thread and try to understand it, also read the original patent for S-Type throttle bodies by Nissan 1987.
- Fuel flow is being compensated accurately by the ECM. I'm getting the all the right ratios where they should be. We don't need tuning.
- Throttle Switch; on/off? This is exactly what you are proposing w/ the tune.
- Please read the service manual, the ECM can compensate for manufacturing variations, it can even compensate w/o the MAF sensor, juts by calculating from MAP sensor, inlet air temp sensor and RPM. As long as the modification occurs within the limits of ECM compensation, no tune is needed.
- You are thinking of times when MAF sensors were very expensive and the air was metered by the throttle blade.
If you don't own a C7 or a Corvette at all, then you don't exactly know what we are talking about. Yes, I'm a Corvette guy and so are most people in this forum. Please, let us leave this aside. This is exactly where we don't want this thread to go.
Good luck to you too!
Last edited by Mike@SolerEngr; 02-26-2019 at 03:08 PM.
Reason: Added signature
01-15-2019, 06:59 PM
