Ford Performance GT350 M-5300-W spring and GT350R spring comparison

I was lucky enough to meet up with and spend some time with Bruce Smith from Ford Racing a few months ago at PRI in Indy. He's a vehicle dynamics guru and top notch engineer and most recently is the man behind the FP350S (among other notable projects/parts). While he wasn't in a position to comment on other upcoming parts he was happy to talk about springs that were nearing release from FRP. In case you are wondering, the M-5300-W GT350 springs are not made by Eibach.

When I got home I called the Ford Racing dealer I have dealt with for nearly 30 years now, Mike and Belinda at Buyfordracing. He's located not far from FR and has been in the game so long that when I'm trying to find out more information or obscure/discontinued parts, he always makes it happen. So while the springs weren't available at the time, Mike took my order such that I'd get them the moment they became available. That moment was a couple of hours ago.





I also picked up a set of the GT350 R springs from Autonation (formerly Tousley) not long ago. Because spring prices don't break the bank I wanted to be able to compare the FRP to the R springs before making a choice. Here's what I saw.

First, the fronts. R in black and FRP in blue (same for all springs). Note that the GT350 chassis uses the same spring up front for either side (in either standard or R rates). Number of coils looks to be the same.






Rears. Note that the springs are counterwound, meaning that the springs are side-specific. Free heights on all springs are near identical but you can clearly see more coils on the FRP springs.






Note that the FRP rear springs indicate left or right by placing the appropriate letter after the part number on each spring.





Also, the FRP rear springs don't come with the OEM split sleeve that you see on the R or non-R GT350 springs. You could transfer the sleeve over if you feel you need them.





Coil thickness up front, FRP.





Front GT350 R.





Rear, FRP.





Rear, GT350 R.




Interesting to note that the FRP rears utilize an additional coil but that the diameter is smaller than the R rear springs and that the fronts are near identical across the board. The specs from FRP indicate a 20mm drop (or about 3/4") on all fours when compared to non-R GT350's. Personally, I'm looking forward to everyone in the group buy getting their springs too and seeing them installed. Mine won't go in until I have some caster/camber plates in hand.

Anyway, thanks FRP for making a GT350 spring available.

Outstanding info and it's a 1/2 inch drop with the frpp springs

Thanks for the info! :cheers: I'm curious to see what people think of the FRP springs.

Do you have the spring rates?

Cool to see that you got them so quick

Gogoggansgo said:

Outstanding info and it's a 1/2 inch drop with the frpp springs

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Quoted from FRP as a 3/4" drop when using a non-R car to begin with. Not sure where you are getting the 1/2" number as this is a "just off the shelf" new part.

ford20 said:

Do you have the spring rates?

Cool to see that you got them so quick

Click to expand...

With the above wire diameters and numbers of coils, you should be able to do some math with free heights. I can get those later if you'd like. FRP doesn't quote rates but I believe Terry at Vorshlag has done much of the legwork already, just not on the FRP springs.

And as to receiving them quickly, as I mentioned, nobody beats Buyfordracing. 50Deep is making it happen with Autonation though and you guys should get yours shortly too.

Thanks for an excellent report.

I am tying to figure out what these springs achieve. If installed on an R, does it lower the car? How much (1/2 in)? Its already dragging the ground. Are they supposed to be stiffer? Will the different rates upset the mag calibration?

Thanks for any feedback.

tdzee said:

Thanks for an excellent report.

I am tying to figure out what these springs achieve. If installed on an R, does it lower the car? How much (1/2 in)? Its already dragging the ground. Are they supposed to be stiffer? Will the different rates upset the mag calibration?

Thanks for any feedback.

Click to expand...

I linked it up above but it looks to be getting missed.




R cars use a shorter tire and there has been mention of either zero drop or 1/4" drop when R springs are installed on a non-R. So aside from speculation, we are going to need to see an R owner take this one on and document the results.

The link says (and I've been told personally) that the factory Mag calibration won't get upset over the spring change. I'd still prepare to recalibrate the ride height sensors, regardless.

Thank so for the write up brother... personally, as I scrape near bout everything in town, I can't imagine my R being 20mm closer to the ground, I have a Watson bar and Vorslag camber plates coming soon. I may need the added heft of the extra coil in the rear.

That being said, it appears the fronts are R specific and the rears are a little more aggressive than the stock R spring. That also being said, I could see the rear of an R squatting towards the rear a little more (would like that a little) and suggest that would drop the car by possibly 7-10mm at center point (rough estimate).

I'm in for a set if you can get me some.

Looks like I'll have to slap some paint on mine when I get them. Can't have blue springs on my Race Red.

Any chance of getting the spring rates checked to compare them to the R springs?
I'd pitch in some $$$ to help.

Thanks for the great write up Epiphany, as always!

Now let's get some members to install them to see the drop and get some spring rates!

The fronts are going to be the same rate as the "R" spring since the wire diameter and the number of coils is the same. The free length must be shorter to make the difference, but they sure look similar in the picture.

bpracer said:

The fronts are going to be the same rate as the "R" spring since the wire diameter and the number of coils is the same. The free length must be shorter to make the difference, but they sure look similar in the picture.

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That's not entirely true. They could be made of a different spring steel or have a different temper.

Redline8250 said:

That's not entirely true. They could be made of a different spring steel or have a different temper.

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While that is true. if they were made out of stouter steel, they would have to be more visually shorter.

I'm just saying if you're looking for something stiffer than the R springs (which I have) for a car running slicks or stickier tires than SC2s then these probably aren't going to do you any good other than looks.

I provided the R springs for Vorschlag to rate against my stock Track Pack springs.

Epiphany - check the wire diameter of the rear spring over its entire length. The Track Pack spring does not to use a constant wire diameter. At the area where it goes into coil bind, they are smaller diameter wire. Not the typical thing you see...

bpracer said:

While that is true. if they were made out of stouter steel, they would have to be more visually shorter.

I'm just saying if you're looking for something stiffer than the R springs (which I have) for a car running slicks or stickier tires than SC2s then these probably aren't going to do you any good other than looks.

I provided the R springs for Vorschlag to rate against my stock Track Pack springs.

Epiphany - check the wire diameter of the rear spring over its entire length. The Track Pack spring does not to use a constant wire diameter. At the area where it goes into coil bind, they are smaller diameter wire. Not the typical thing you see...

Click to expand...

Not sure you remember me but my old user name was voodooo. I remember you testing the plates and springs for Vorshlag.
I also have R springs, vorshlag plates, cortex monoball suspension bearings etc but run a Sport cup 2.
Correct I agree. I'm aware the track pack spring has a tapered wire diameter.
But until we measure the spring rates we'll never know.