Throttle Response, Beyond Porting
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There is a much debated problem w/ the throttle response of the LT1/LT4 engines, manual or auto, the issue has been described in this and other forums (Corvette, Camaro, CTS-V, Trucks, SUV’s), just to mention a few descriptions:
- Throttle Lag - Delayed response - Car feeling heavy or not nimble - Difficulty climbing hills at low/moderate throttle - Uncertainty when passing other cars or unpredictable response at low/moderate throttle - Stumble when shifting on manual transmissions You name it, this has been my issue w/ my Corvette 7 since test driving at the dealership. I've tried a Throttle controller, AFM disabler, ECM Tuning, and arguably the three most talked about ported throttle bodies (PTB) out there. I have also combined some of the above w/ some success but still not enough. One just needs to hop into almost any other comparable car to feel they respond better. After spending so much time/money, I decided to take it upon myself to find out, I also have all the equipment needed at work (measuring, testing, simulating, machining etc.) Long story short; it is the throttle body. Between idle (~5 degree throttle) to ~30 deg throttle angle the amount of mass air flow (which is proportional to power) puts our cars at a weigh to power ratio similar to that of trucks and SUV’s, both in terms of absolute value and rate of change. Not to be confused w/ the weight to power ratio that is usually published, which is calculated at WOT, above 35 deg throttle angle our engines shine. It is on the part throttle range (idle to 30 deg) that the issue exists. I’m not going to speculate on the reasons, but I can tell you that our throttle body p/n 12678223 or 12620263 is used in many GM vehicles and that such throttle response helps w/ fuel economy. That helps to keep parts cost low and meet EPA requirements for the fleet. However, I do not think one size fits all and that a high performance car needs to sacrifice performance for economy. The throttle controller and the tune improve response by making the throttle plate move faster between the 5-30 deg range. Faster, but it still needs to go through a tortuous path for the air flow, and the manifold pressure doesn’t recover as fast. It is a transient process, and it is from the intake manifold where the pistons suck the air from. Notice that this is not true throttle response, it is just tricking the ECM into thinking you have pushed the accelerator pedal harder. The actual throttle response is the same, only physical changes to the throttle can make for a true throttle response. The existing aftermarket ported throttle bodies also helped, they do change the throttle physically, but their effect only starts to take place at about 25 deg in what I thought was the best one of them. Definitely a step in the right direction, but I noticed they were not optimized and that more could be extracted from them, that is a throttle body that can increase the absolute value and rate of change of mass air flow right from idle and up to 35 degrees to achieve the same weight to power ratio (in that range) of similar high performance cars that feel nimble and fun to drive at part throttle. Another long story short, I reversed engineered 10ea OEM throttle bodies, 3ea aftermarket ported throttle bodies, and a benchmark (competing car maker model) OEM throttle body. Optimized/modified the OEM throttle body to meet the benchmark throttle response as well as the goal stated above. Our modified throttle bodies (MTB) are made (CNC machined) from a brand new OEM throttle body, flow and engine tested. Our design has been fully vetted by Corvette 7, Camaro 6, CTS-V owners, fully and openly tested by Corvette Forum members mainly. Driven in different conditions/modes for a few thousands of miles now at extreme temperatures and altitudes. See pics below for more insight into what I’m talking about…and most importantly what do you think? All comments welcome. Please visit us at : SolerEngineering.com Thanks, |
very cool, I'm impressed, but i'm not an engineer so that's probably not saying much.
I assume no tune required? |
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Thanks, DenverTaco07. Correct, no tune required. Installation instructions attached for a Corvette 7. Very similar for a Camaro 6.
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Does the throttle response issue have anything to do with this being a throttle by wire setup instead of a physical connection between pedal and throttle body?
And also , Would this void the warranty ? |
id love to hear real world dyno results
and not for nothing this is how you do a product launch not like some unnamed cold air intakes! |
warranty voiding technically can only occur on products/modifications that can be proven to be the cause of the warranty work needed.
However, dealers and even OEM's will fight you and say the warranty is voided even though legally they aren't allowed to. You'll then have to pay for a lawyer to fight them. So the short answer is always, if you care about the warranty being voided, dont do it. Stick to stock. Or you know, just stop caring about the warranty and do what you want. |
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Voiding the warranty is easily and completely under your control. It is widely considered a non-warranty buster Mod for that reason. |
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At WOT, you know how inaccurate chassis dynos can be, but we'll run back to back dynos and see what we get. Some numbers we could give right now is that your effective bore diameter goes from 87 mm (stock) to 91 mm (with mod). Our inlet/outlet design make flow much more efficient, polished to reduce skin friction, even the screws are completely out of the way. All these will show up at WOT we expect an easy 10-20+ HP gain. Some Corvettes have taken our TB's to the track, and just the smoothness and predictability makes them track worthy. Thanks, |
What about on a cammed Procharged car? Would it be worth the switch since the Procharger is cramming air into the motor?
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We could certainly send one configuration that will work the 1st time and that still outperforms the competition, but that wouldn't be optimum for your setup and that is not our promise, but could consider if you don't feel like installing a couple of times. Update: Just looked at our records, we have 4 Procharger and 3 A&A (very similar blower) customers. All Corvettes 7's (LT1) So, we have a pretty good idea of what will work for you. |
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One thing I want to point out/comment: about the ported throttle bodies out there and not starting to do anything until about 25-degrees - Are your comments in respect to the theoretical 0-degree point (fully vertical; like your example sketch/drawing) of the throttle blade or in respect to their true, as-built rest position (which is NOT completely vertical)? Reason being as this is important to keep in mind with what you have posted and the work you have done. P.S. - Appreciate the write up and the work you and your company did. |
Do you make one for a 5th gen ZL1 with a LSA engine?
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Sent from my SM-G955U using Tapatalk |
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Minimum flow does not occur at the physical zero degrees (vertical). It happens at about 1-2 degrees (This is the "zero" for results plotted). |
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