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Rear Suspension Upgrade In Progress (Powdercoat Inside!!)
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<blockquote data-quote="ac427cobra" data-source="post: 10437292" data-attributes="member: 6247"><p>When I say 'hardly any' I mean 'barely noticeable'. I'd be willing to bet you would not be able to tell the difference, riding as a passenger blindfolded, between a stock IRS and an IRS that has had only a Delrin control arm bushing change. The only difference would be the Delrin bushed IRS will be a 'smoother' ride because the shocks and springs won't be fighting the bound up OEM rubber control arm bushings. NVH differences will be virtually undetectable. </p><p></p><p>When I say a 'smoother' ride I'm referring to this comparison of bound up OEM rubber control arm bushings:</p><p></p><p></p><p><a href="http://www.fulltiltboogieracing.com/Videos/OEM%20control%20arm%20demostration.mpg" target="_blank">bound up OEM rubber IRS control arm bushings</a></p><p></p><p></p><p></p><p>As compared to freely articulating FTBR Delrin IRS control arm bushings:</p><p></p><p></p><p></p><p><a href="http://www.fulltiltboogieracing.com/Videos/FTBR%20DELRIN%20CONTROL%20ARMS.mpg" target="_blank">no more bound up OEM rubber</a> </p><p></p><p></p><p></p><p></p><p>Rubber bushings are mass produced and cheap for manufacturers to use. They isolate NHV well but compromise suspension horrifically, particularly when loaded. That's why racers and performance minded people focus on removing rubber as a first and top priority. </p><p></p><p></p><p></p><p>I would compare this comment to someone putting a Kenne Bell on their car and saying DAMN that thing is noisy, I'm not sure I'm happy with it! :read:</p><p></p><p></p><p></p><p>The Delrin control arm bushings in the IRS <strong>cannot</strong> be compared to a CC plate on the front of the car. The CC plate is a direct vertical attachment to the chassis. In the rear, the car is being supported by the knuckle and the rear spring (non-coil-over application) and the Delrin control arm bushings are merely the articulation attachment point. </p><p></p><p></p><p></p><p></p><p>Gear whine is gear whine. The slower the gears are meshing at lower speeds the less noise will be generated. At higher speeds db levels will increase as they mesh together faster and faster. </p><p></p><p>A lot of factors come into play as you've stated. With the windows up, wind noise will <strong>not</strong> mask gear noise, windows down, yes. </p><p></p><p>One item in particular that will mask elevated NVH levels is exhaust noise which is one of the things I list on our website:</p><p></p><p><a href="http://www.fulltiltboogieracing.com/faqs.htm" target="_blank">FTBR Frequently Asked Questions</a></p><p></p><p>when discussing the raised NVH levels of the front diff mounts:</p><p></p><p>Q: "How much increase in NVH will I see with this kit?"</p><p></p><p>A: The change in NVH will hardly be noticeable with the exception of the aluminum front differential mounts. They are a tad on the noisy side. Worse if you have 4:10 gears. If you have an aftermarket exhaust that's loud, it will help mask the noise from the diff mounts. Some have used the sound deadening matting available at car stereo shops to minimize the sound. It's a self adhesive matting you put down on the floor pan right above the differential. It's called Dynamat and it's also available at Eastwood.</p><p></p><p> Q: "How bad will the noise level be with 4:10's?"</p><p></p><p>A: 4:10's are definitely going to raise the noise level particularly with the Aluminum front diff mounts. As mentioned above, if you have loud aftermarket exhaust, that will help. Some people put down Dynamat on the floorpan directly above the differential and that seems to help a lot. Some say it's noisy, and others have said it's not bad. It's like asking what the best beer is. You won't get the same answer from any two people.</p><p></p><p></p><p></p><p>A few years ago I installed our kit in a customer's car and he had a pretty loud exhaust system. I could not hear ANY difference in NVH levels in his car after the install and neither could he. </p><p></p><p></p><p></p><p></p><p>I try to explain what people should expect with this kit to the best of my ability. I can honestly tell you that we have had<strong> MANY </strong>people comment, as the OP has stated in post #75 in this thread, that he has heard no difference in NVH. Right away, I know he has to have a fairly loud exhaust to make this statement. </p><p></p><p>We've also heard the majority of our customers say they can hear an elevated level of NVH but the complete transformation of performance and handling they have seen in their car after the installation of the kit makes it more than worth it putting up with a little additional noise. </p><p></p><p>We've also had people say it's pretty loud and these are the people that most likely are still on stock exhaust or a pretty quiet aftermarket system. I suggest the Dynamatting procedure to these people. </p><p></p><p>I think we've only had one or two people in the approximate 1,000+ kits we've sold to date say OMG I have to take those front diff mounts out of the car. </p><p></p><p>:thumbsup::coolman::beer:</p></blockquote><p></p>
[QUOTE="ac427cobra, post: 10437292, member: 6247"] When I say 'hardly any' I mean 'barely noticeable'. I'd be willing to bet you would not be able to tell the difference, riding as a passenger blindfolded, between a stock IRS and an IRS that has had only a Delrin control arm bushing change. The only difference would be the Delrin bushed IRS will be a 'smoother' ride because the shocks and springs won't be fighting the bound up OEM rubber control arm bushings. NVH differences will be virtually undetectable. When I say a 'smoother' ride I'm referring to this comparison of bound up OEM rubber control arm bushings: [URL="http://www.fulltiltboogieracing.com/Videos/OEM%20control%20arm%20demostration.mpg"]bound up OEM rubber IRS control arm bushings[/URL] As compared to freely articulating FTBR Delrin IRS control arm bushings: [URL="http://www.fulltiltboogieracing.com/Videos/FTBR%20DELRIN%20CONTROL%20ARMS.mpg"]no more bound up OEM rubber[/URL] Rubber bushings are mass produced and cheap for manufacturers to use. They isolate NHV well but compromise suspension horrifically, particularly when loaded. That's why racers and performance minded people focus on removing rubber as a first and top priority. I would compare this comment to someone putting a Kenne Bell on their car and saying DAMN that thing is noisy, I'm not sure I'm happy with it! :read: The Delrin control arm bushings in the IRS [B]cannot[/B] be compared to a CC plate on the front of the car. The CC plate is a direct vertical attachment to the chassis. In the rear, the car is being supported by the knuckle and the rear spring (non-coil-over application) and the Delrin control arm bushings are merely the articulation attachment point. Gear whine is gear whine. The slower the gears are meshing at lower speeds the less noise will be generated. At higher speeds db levels will increase as they mesh together faster and faster. A lot of factors come into play as you've stated. With the windows up, wind noise will [B]not[/B] mask gear noise, windows down, yes. One item in particular that will mask elevated NVH levels is exhaust noise which is one of the things I list on our website: [url=http://www.fulltiltboogieracing.com/faqs.htm]FTBR Frequently Asked Questions[/url] when discussing the raised NVH levels of the front diff mounts: Q: "How much increase in NVH will I see with this kit?" A: The change in NVH will hardly be noticeable with the exception of the aluminum front differential mounts. They are a tad on the noisy side. Worse if you have 4:10 gears. If you have an aftermarket exhaust that's loud, it will help mask the noise from the diff mounts. Some have used the sound deadening matting available at car stereo shops to minimize the sound. It's a self adhesive matting you put down on the floor pan right above the differential. It's called Dynamat and it's also available at Eastwood. Q: "How bad will the noise level be with 4:10's?" A: 4:10's are definitely going to raise the noise level particularly with the Aluminum front diff mounts. As mentioned above, if you have loud aftermarket exhaust, that will help. Some people put down Dynamat on the floorpan directly above the differential and that seems to help a lot. Some say it's noisy, and others have said it's not bad. It's like asking what the best beer is. You won't get the same answer from any two people. A few years ago I installed our kit in a customer's car and he had a pretty loud exhaust system. I could not hear ANY difference in NVH levels in his car after the install and neither could he. I try to explain what people should expect with this kit to the best of my ability. I can honestly tell you that we have had[B] MANY [/B]people comment, as the OP has stated in post #75 in this thread, that he has heard no difference in NVH. Right away, I know he has to have a fairly loud exhaust to make this statement. We've also heard the majority of our customers say they can hear an elevated level of NVH but the complete transformation of performance and handling they have seen in their car after the installation of the kit makes it more than worth it putting up with a little additional noise. We've also had people say it's pretty loud and these are the people that most likely are still on stock exhaust or a pretty quiet aftermarket system. I suggest the Dynamatting procedure to these people. I think we've only had one or two people in the approximate 1,000+ kits we've sold to date say OMG I have to take those front diff mounts out of the car. :thumbsup::coolman::beer: [/QUOTE]
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