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Full Version: What do I really need to re-enforce with a 400 HP car?
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Gearup
Gents,
I already have purchased Mad Dogs GT steel reinforcement panels for the wheel well and surrounding area. I am seriously considering purchasing the Longs reinforcemen panels as well and “maybe” the trailing arm kit. Gents, what do I really need? It’s gonna be a street car for me but I don’t want to short change the build. The trailing arm reinforcement has been hotly debated here in the past. ANY input from people here with direct knowledge would really be appreciated. My car is at a
Spot where now would be the time to do whatever I end up deciding. Power will be and LS1 with possibly a mild cam. 380-430 HP ish.
Thank you very much,
Brett
mepstein
I buy into the theory that the trailing arms bend before the chassis and they are cheap to replace. I would buy or make a suspension console reinforcement, like what tangerine racing has. It's not as much the HP as the wide tires that rip the pivots from the consoles. The Brad Mayer long kit is the one to get if you don't care about originality.
Gearup
QUOTE(mepstein @ Nov 7 2019, 06:24 PM) *

I buy into the theory that the trailing arms bend before the chassis and they are cheap to replace. I would buy or make a suspension console reinforcement, like what tangerine racing has. It's not as much the HP as the wide tires that rip the pivots from the consoles. The Brad Mayer long kit is the one to get if you don't care about originality.


Mad Dogs longitudinal reinforcement goes on the inside (cab) Brads on the outside as I recall. Brads are a fair amount more expensive. Worth the extra expense? How difficult is the install for a Good
Welder? Thank you for responding.
tygaboy
Remember, you're more than 4x-ing the amount of power that the car came with.
I would do the Mad Dog inner long kit and Tangerine's suspension ear kit.
I wouldn't do the GT chassis kit or worry about the trailing arms, given it's a street car.
I you want to upgrade the trailing arms, contact Tangerine Racing and have Chris do his thing to them. It's far better than the GT kit. It's what I went with on my 500+ hp LS build.

Brad's kit is very stout, for sure. But I'd say do the above stuff and see if you think you need more.

Of course, there's always a cage. And there are "safe for the street" options for cages.
Gearup
QUOTE(tygaboy @ Nov 7 2019, 06:35 PM) *

Remember, you're more than 4x-ing the amount of power that the car came with.
I would do the Mad Dog inner long kit and Tangerine's suspension ear kit.
I wouldn't do the GT kit or worry about the trailing arms.

Brad's kit is very stout, for sure. But I'd say do the above stuff and see if you think you need more.

Of course, there's always a cage. And there are "safe for the street" options for cages.


Do you know of a Safe for street cage source. Renegade offers one but only if they install it as they have had major fitment issues when sent out. A cage would be reinforcement by itself. Correct. Maybe the dog ears too?
Chi-town
The last car I built flexed more than I liked with a stock 1.8 laugh.gif

Things I would recommend:

A full cage tied into the rear trans mounts and engine mount points

A functional reinforcement of the trailing arms and mounting points.

When I say functional I mean something better than heavy metal plates welded all over. This isn't 1970 there are better ways without adding 50+lbs to the car (sprung and unsprung).
tygaboy
QUOTE(Gearup @ Nov 7 2019, 06:39 PM) *

QUOTE(tygaboy @ Nov 7 2019, 06:35 PM) *

Remember, you're more than 4x-ing the amount of power that the car came with.
I would do the Mad Dog inner long kit and Tangerine's suspension ear kit.
I wouldn't do the GT kit or worry about the trailing arms.

Brad's kit is very stout, for sure. But I'd say do the above stuff and see if you think you need more.

Of course, there's always a cage. And there are "safe for the street" options for cages.


Do you know of a Safe for street cage source. Renegade offers one but only if they install it as they have had major fitment issues when sent out. A cage would be reinforcement by itself. Correct. Maybe the dog ears too?


Well, I have the advantage of being able to fabricate my own cage and other stuff.
If it were me, I'd do a front hoop and a rear hoop and join them with "inset" connector bars., sort of like a wide T-top. Clearance for heads but prevents the main front/back chassis flex. Not as strong as a full race cage but again, you're talking about a street car.
Krieger
QUOTE(Gearup @ Nov 7 2019, 06:39 PM) *

QUOTE(tygaboy @ Nov 7 2019, 06:35 PM) *

Remember, you're more than 4x-ing the amount of power that the car came with.
I would do the Mad Dog inner long kit and Tangerine's suspension ear kit.
I wouldn't do the GT kit or worry about the trailing arms.

Brad's kit is very stout, for sure. But I'd say do the above stuff and see if you think you need more.

Of course, there's always a cage. And there are "safe for the street" options for cages.


Do you know of a Safe for street cage source. Renegade offers one but only if they install it as they have had major fitment issues when sent out. A cage would be reinforcement by itself. Correct. Maybe the dog ears too?


Talk to Chris @ Tangerine racing he makes cages.
Krieger
Chris has cages with strippers too! If you need them! lol-2.gif
Andyrew
All 914's need the longs reinforced.

400hp or more importantly the torque needs really nothing else, your not going to rip the body up on the street, you'll just spin the tires or go... The chassis isnt going to "twist"

Personally I think the following is necessary for any 914 thats going to be driven hard.

1. Long reinforcement
2. Rear suspension ear reinforcement + brace
3. Outer trailing arm reinforcement



I dont think the "GT" kit does anything except for the outer trailing arm reinforcement.


I think a bar from the front trunk firewall to the front suspension front mount is important in the long run for conversion cars due to the cutout in the wheel wells, but after 15 years I still dont see any tearing and mine are ugly...


Also one last thing to note, the biggest thing your going to notice is if you actually cage the car... That is a serious night and day difference in the way the car feels.
Chi-town
The plates for the trailing arms are a waste. If you look at the arm it will flex at the tube long before the boxed section. It's just simple leverage.

Anyone ever wonder why the arm shafts are all bent?

If you do a simple 4 point cage in the interior you can skip the long plates also.
ClayPerrine
QUOTE(Andyrew @ Nov 7 2019, 09:59 PM) *


400hp or more importantly the torque needs really nothing else, your not going to rip the body up on the street, you'll just spin the tires or go... The chassis isnt going to "twist"



Yes the chassis will flex. I have a 4.0L 964 engine and I broke the left rear top catch in two due to chassis flex. It actually snapped the part that bolts to the top into two pieces. I have a Brad Mauyer kit and a GT stiffening kit on my car. My solution is going to be to put in a bolt in GT style top with the steel cross bracing.




Andyrew
QUOTE(ClayPerrine @ Nov 8 2019, 05:13 AM) *

QUOTE(Andyrew @ Nov 7 2019, 09:59 PM) *


400hp or more importantly the torque needs really nothing else, your not going to rip the body up on the street, you'll just spin the tires or go... The chassis isnt going to "twist"



Yes the chassis will flex. I have a 4.0L 964 engine and I broke the left rear top catch in two due to chassis flex. It actually snapped the part that bolts to the top into two pieces. I have a Brad Mauyer kit and a GT stiffening kit on my car. My solution is going to be to put in a bolt in GT style top with the steel cross bracing.

Flex vs twist smile.gif

Flex is good for preventing damage as that means something is absorbing the force.

Twist (in what I'm describing) is a permanent change in the body structure.



Did you break that on a twisty road when you hit a pothole or at a track getting on power mid turn?
mepstein
The best way would be to assemble the car and run it to see what you need, add the reinforcement as needed and then finish the car. It sounds like more work than doing it all at once but in the long run it’s probably more efficient to do metalwork and finish than to guess at what is needed with metalwork and mechanical, finish and then go back and work on a finished car (painted) with updates.
Tdskip
Long kit isn’t that hard to do if the interior is out - makes a BIG difference. As Dylan said so will a proper rollbar in the cockpit.
RickS
With 400hp I would recommend your sphincter.
rick 918-S
Never reinforced the Alien assimilate.gif confused24.gif Drive the he'll out of it. driving.gif
ClayPerrine
QUOTE(Andyrew @ Nov 8 2019, 07:31 AM) *

QUOTE(ClayPerrine @ Nov 8 2019, 05:13 AM) *

QUOTE(Andyrew @ Nov 7 2019, 09:59 PM) *


400hp or more importantly the torque needs really nothing else, your not going to rip the body up on the street, you'll just spin the tires or go... The chassis isnt going to "twist"



Yes the chassis will flex. I have a 4.0L 964 engine and I broke the left rear top catch in two due to chassis flex. It actually snapped the part that bolts to the top into two pieces. I have a Brad Mauyer kit and a GT stiffening kit on my car. My solution is going to be to put in a bolt in GT style top with the steel cross bracing.

Flex vs twist smile.gif

Flex is good for preventing damage as that means something is absorbing the force.

Twist (in what I'm describing) is a permanent change in the body structure.



Did you break that on a twisty road when you hit a pothole or at a track getting on power mid turn?



It happened at an AX, but I don't know when during the run. I got out of the car, and it just fell on me.
Andyrew
Sticky tires or streets?

The top moves quite a bit on the 914. I can see how the latch would snap at an autox but this isn't an indication of permanent damage to the chassis, just the body flexing.
Superhawk996
Smart aleck response coming in 3 ... 2 ... 1

Reinforce the whole car. You really have to ask yourself what you hope to gain with 400 HP in a Targa. Look to the 916 and ask why Porshe would put a welded on roof on it with far less than 400 HP on tap.

Cage it! happy11.gif
Superhawk996
QUOTE(RickS @ Nov 9 2019, 01:56 AM) *

With 400hp I would recommend your sphincter.



happy11.gif av-943.gif lol-2.gif



Gearup
Who sells a bolt in ready cage that is good on the street for a decent price. BTW thanks for all the great responses. Even the one mentioning re-enforcing my sphincter. My wife says I might as well weld it shut as she will put her foot up there if I keep spending money on the project:)!
Superhawk996
QUOTE(Gearup @ Nov 9 2019, 05:52 PM) *

Who sells a bolt in ready cage that is good on the street for a decent price. BTW thanks for all the great responses. Even the one mentioning re-enforcing my sphincter. My wife says I might as well weld it shut as she will put her foot up there if I keep spending money on the project:)!


I love your sense of humor! lol-2.gif

I'm not sure you'll find a bolt in ready cage. Tangerine Racing is your best bet. However, beware of cages for street use. Knocking your head on a cage during a relatively minor incident without a helmet can be very deadly.

At a bare minimum, look into the 916 roof structure. You need structure up top. Targa bodies have notoriously low torsional stiffness vs. a coupe with a roof structure.

Tangerine also offers some stiffening for the rear suspension console. This console is where your tractive drive forces are reacted against to push the car. They need to be beefed up with 400 HP as they weren't designed for that kind of loading.
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