First Gen F Body Subframe... Another angle

[XLexusTech]

HI. Couple of things up front.
I am frugal not rich, some might even say cheap. However will spend the $$ on things that work. I have a bent OE subframe.

So here it goes.
My plan in to put the car on the road with the Gen 1 SBC and then the following winter switch to a LS series SB.

They way I look @ it to replace the Subframe with anoter stock one,
400 to 500 just for the bare sub another 200 to 500 T&M to clean reweld and coat/paint. By the time I get all of the pieces needeed to run the LS engine its going to start to add up.



I have been watching various subframes and read many posts about them. The conclusion I have drawn is that thier are a few that are great. In terms of performance you can pretty much get a stock subframe to work just as well. For me the real advantage comes in the reported fitmit of the LS engines and the Racks & pinions.

Hopefully I have layed this out clearly. MY question is since I have to replace my sub and I found the speedtech sub for 2K bare. Which way would you go? Buy another OE or the speed tech one?

[Steve Firebird]

I think you maybe able to pick up a stock subframe for less then 400.00 if you keep and eye out. The real question in my eyes is how much of the work you will do your self on preping the frame. If you are going to hire all the work done I would bet the aftermarket frame would be the best deal in the long run. If you can do all the welding, fabricating and painting on the factory frame that would be the most cost effective.

[silver69camaro]

In terms of performance you can pretty much get a stock subframe to work just as well.

I'd be careful about that. While many characteristics can come fairly close to a good aftermarket frame, don't forget the stock setup is still rear steer and a bit overweight. Aftermarket frames help to allow pretty darn close to a 50/50 weight distribution.

As I've said before, it all comes down to whether the price is worth it. That's up to you of course!

[XLexusTech]

I'd be careful about that. While many characteristics can come fairly close to a good aftermarket frame, don't forget the stock setup is still rear steer and a bit overweight. Aftermarket frames help to allow pretty darn close to a 50/50 weight distribution.

As I've said before, it all comes down to whether the price is worth it. That's up to you of course!

Hi thankss for your response.
My plans for ths stock SUB included the ATS tall spindles I think that would take care of the Geometry/ Do you disagree?
What kind of weight advantage are we taling about?
Can yo provide detials on that? E.G Stock weighs xxx .lbs and DSE weighs ??? or speed tech wehighs ??? CA weighs???

Since unsprug weight is were allot of gains can be made I had planned on the ATS componants and aftermarket arms. The Rack will shave a few lbs.
I relise this is a subjective discussion I appreaciate your thoughts.
To me ita about maksing the best $$l decision while balancing performace. I dont want to be one of those folk who spent $$ on parts and turn out to spend just as much if not more then they would on an aftermarket package.

[silver69camaro]

I understand the position of trying to balance performance and $$. Been there done that, still do it.

Anyway, I can't comment of the weight of other subframes, but I can say that ours can shave 30-40lbs off from stock frame (with power steering). Remember that's all weight right over the front axle too.

As far as geometry goes, specifically rear steer, there isn't anything you can do about it. It's about bushing deflection, and rear steer vehicles will add more steering as bushings deflect under load. Stiffer bushings will help, but it's still there.

[dhutton]

Will the Speedtech subframe allow you to use the stock F body LS1 oil pan and accessories? What about fitting the AC compressor in the stock location? The AME subframe does and the savings can be significant if you are willing to live with the stock accessories. I used a $100 Vintage Air bracket with my AME subframe to mount a Sanden compressor in the factory F body location (low passenger's side). All it needed was a longer belt.

This is one of those cases where you need to do the math comparing the total cost of the options you are considering. Every build is different so it's difficult to say which is the better option without considering all the details.

Don

[nvr2fst]

I have a complete stock subframe for sale if your interested (straight, clean, no cracks etc.). pulled it from the car 4 months ago still has everything attached on it. Im in WI.
dave

[XLexusTech]

Thanks Dave I am a few 1000 miles away and it would liky cost me too much to ship

[nvr2fst]

Thanks Dave I am a few 1000 miles away and it would liky cost me too much to ship

Good point! the shipping cost most likely would be as much as the asking pricehttps://www.pro-touring.com/forum/images/smilies/pat.gif

[BonzoHansen]

Will the Speedtech subframe allow you to use the stock F body LS1 oil pan and accessories?

If I read this right, no.

http://www.speedtech-performance.com...cat/cat214.htm

"...also accepts the LSx series using the ATS (American Touring Specialities)oil pan and motor mount adaptors..."

[XLexusTech]

Bonzo thanks for the heads up. Looks thieir is no reason for me buy the speed tech sub if it requires the same adapters as the oem frame

[Fuelie Fan]

How does your frame compare in terms of stiffness? What material is it made of?

I understand the position of trying to balance performance and $$. Been there done that, still do it.

Anyway, I can't comment of the weight of other subframes, but I can say that ours can shave 30-40lbs off from stock frame (with power steering). Remember that's all weight right over the front axle too.

As far as geometry goes, specifically rear steer, there isn't anything you can do about it. It's about bushing deflection, and rear steer vehicles will add more steering as bushings deflect under load. Stiffer bushings will help, but it's still there.

[DarkoNova]

Bonzo thanks for the heads up. Looks thieir is no reason for me buy the speed tech sub if it requires the same adapters as the oem frame

LOL, not only that, but it's still rear steer. One of the main reasons for buying an aftermarket frame is for front steer, so wtf?!

Matt

[novaderrik]

what makes a rear steer setup inherently bad compared to a front steer setup, besides the marketing $$$ spent by the companies that sell front steer subframes?
in a rear steer, the tie rods are going to be in compression when driving forward, and in a front steer setup they will be getting stretched.
other than that, i can't see any functional difference, and in both cases, the amount of stretch/compression will be minimal and easily compensated for by moving the alignment a degree one way or another.
and how much will you notice the 40 or so pounds take off the nose with an aftermarket frame on your average daily driven car? that's about the same as moving the battery to the trunk or taking the factory AC compressor, lines, and condensor out of an otherwise stock car, which i can tell you makes no noticable difference.
i used a stock 73 nova subframe in my 71 Nova, and with the Guldstrand mod, stock sway bar, Moog 6014 (6041? it's been a few years) springs, stock replacemnt Moog rubber bushings, balljoints, and tie rods, CE solid mounts and a pair of $15 NAPA gas shocks. with a set of junkyard 16X8 GTA wheels and some 245/50/16 Fuzion ZRi tires that thing handled as good as and rode as nice as any stock late model car i've driven.

[Vegas69]

It's really nice to get it out of the way for header clearance, oil lines, oil pans, and steering shaft arrangements in a rack situtation. I can't tell you how glad I am to have it up front. I slid in the drivers header with 2 1/8 primaries and didn't bump one thing. Took me 15 minutes to have it bolted up.

[silver69camaro]

How does your frame compare in terms of stiffness? What material is it made of?

Our subframe is made of ASTM 148 made to our specifications. It is stiffer than stock; however, the stock subframe is fairly stiff to begin with and really isn't a problem. It's the rest of the unibody you have to worry about. Subframe connectors will do FAR more than any aftermarket subframe will to improve chassis stiffness.

[killer69]

Just to give you guys a bit of back ground.
there is a great debate as to weather front steer is better than rear steer????? i don't know the answer, i don't think there is an answer?
our objective with this sub frame was to provide buyers with another option besides converting EVERYTHING, you can still use your existing wheels/ brakes and even your existing after market tubular control arms (if you wanted)
the track width is the same as factory.
we tried a front steer rack in the begining and honestly it doesnt work sa well with the factory control arms as the rear steer. we made it work on franks car due to his oil pan requirements but we opted to make it rear steer, we tried to make it as modular as possible so a guy could build and upgrade in stages if he wanted. due to the how popular air ride is we made that able to bolt on.
as for the LS oil pan we have only test fit with the ATS oil pan, but if the modified pan fits a stock sub there is really no reason it won't fit the new sub ( if anyone has a modified pan and wants to send it i will test fit it) the factory a/c looks like it will be tight we have been waiting for a factory a/c compressor for a while now to test it, the concept one will work the Billet specialities one will be very close also.

so that was our design criteria
any questions feel free to call