Subframe mod question
#1
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Car: 88 GTA
Engine: 2001 ls1
Transmission: T56
Axle/Gears: TNT 8.8
Subframe mod question
Got to thinking, Thirdgens have two big complaints against them from the car world
1: exhaust clearance! It's terrible, there's no room for any decent dual pipe to tuck happily.
2: The "thirdgen" squeaks, clunks, rattles from chassis flex.
So I've been poking around different threads to maybe find a fix for these problems. It seems that the common denominator is the front frame boxes. They cause most of the issue. We often mitigate the problem with subframe connectors but still don't have the clearance we need for exhaust.
Is it possible to completely remove the frame boxes and "frame" the car? tie one bar from the front frame to the back frame on each side. I mean, we already buy a giant bar with subframe connectors, why not connect the subframes through the floor. Strengthen the chassis AND be able to run exhaust under the tunnel. Granted it's a longer, tougher road but I see significant benefits over the typical flight pattern.
Any thoughts or insight on this?
1: exhaust clearance! It's terrible, there's no room for any decent dual pipe to tuck happily.
2: The "thirdgen" squeaks, clunks, rattles from chassis flex.
So I've been poking around different threads to maybe find a fix for these problems. It seems that the common denominator is the front frame boxes. They cause most of the issue. We often mitigate the problem with subframe connectors but still don't have the clearance we need for exhaust.
Is it possible to completely remove the frame boxes and "frame" the car? tie one bar from the front frame to the back frame on each side. I mean, we already buy a giant bar with subframe connectors, why not connect the subframes through the floor. Strengthen the chassis AND be able to run exhaust under the tunnel. Granted it's a longer, tougher road but I see significant benefits over the typical flight pattern.
Any thoughts or insight on this?
#2
Member
Re: Subframe mod question
20141203 184004
20141107 234154
20141108 013625
There is PLENTY of room down there as you can see in the pictures. All of those items are installed on that car in the side view shot, great ground clearance. The converters are the lowest point of the system, if removed it would then be the headers. Nothing touches any other component, nothing bangs or rattles, nothing is crushed to fit, the system is round from front to rear.
#5
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Re: Subframe mod question
Those are Random Technologies free flow cats for 2 1/2 inch tubing. They are awfully similar to the factory cats on my 99 silverado.
#7
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Re: Subframe mod question
There is PLENTY of room down there as you can see in the pictures. All of those items are installed on that car in the side view shot, great ground clearance. The converters are the lowest point of the system, if removed it would then be the headers. Nothing touches any other component, nothing bangs or rattles, nothing is crushed to fit, the system is round from front to rear.
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#8
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Re: Subframe mod question
I made the frame connectors along with the crossmember, they all bolt up and work together.
#9
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Car: 1986 Firebird TA
Engine: SBC 350
Transmission: TH350 Stage2
Axle/Gears: 9 Bolt rebuilt w/3.70
Re: Subframe mod question
I would say that is some very good fabing and welding. I would buy those in a heart beat. They look clean and fit like a charm. My duals dump out by under the axle. I don't get emission tested so no coverters and race bullet mufflers on mine.
#10
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Car: '90 RS
Engine: 377 LSX
Transmission: Magnum T56
Re: Subframe mod question
Is it possible to completely remove the frame boxes and "frame" the car? tie one bar from the front frame to the back frame on each side. I mean, we already buy a giant bar with subframe connectors, why not connect the subframes through the floor. Strengthen the chassis AND be able to run exhaust under the tunnel. Granted it's a longer, tougher road but I see significant benefits over the typical flight pattern.
Any thoughts or insight on this?
The DSE subframe connectors basically do exactly this. You cut through the floor, and their kit ties the front frame to the rear. When installed it is no lower than your pinch weld (which also is typically chewed up).
#11
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Car: 92 camaro, 06 trailblazer ss
Engine: 5.0 tbi, 6.0 ls2
Re: Subframe mod question
i like the look and function of the Detroit speed sfc's they tie in well and have no ground clearance issues but I'm not going over the rear for exhaust either.
#12
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Re: Subframe mod question
If you can weld decently, have a chop saw and can buy the appropriate metal then buying sudframe connectors is a big waste of money vs making your own. Case in point, the solid motor mounts spohn makes sell for $150 and I made my own copy for $5-10. I did the same for my inner subframe connectors. Members on here have also removed the factory subframe rails and welded in their own, that's something I wish I had done on my car!
#13
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Car: '90 RS
Engine: 377 LSX
Transmission: Magnum T56
Re: Subframe mod question
If you can weld decently, have a chop saw and can buy the appropriate metal then buying sudframe connectors is a big waste of money vs making your own. Case in point, the solid motor mounts spohn makes sell for $150 and I made my own copy for $5-10. I did the same for my inner subframe connectors. Members on here have also removed the factory subframe rails and welded in their own, that's something I wish I had done on my car!
#14
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Re: Subframe mod question
I agree but it's all in the opportunity cost. Some folks, party included, have very limited time, so much so that a few hundred bucks is cheaper than our time. However, to your point, these cars are simple enough where DIY fab work is very doable and cost effective.
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Tidan (07-23-2020)
#15
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Re: Subframe mod question
I understand what shifty is saying but I think you and I are of a similar mindset now. I've read about and had enough experience with ill fitting products that, if possible, make me want to fabricate my own parts.
Last edited by Tibo; 11-04-2018 at 09:39 AM.
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