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Longest possible shocks for Ironman springs


KiwiTerrano
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Hi all, been lurking here for a couple of month since acquiring my Terrano. It's a 1997 JDM G3M-R Limited model, powered by the QD32ETi diesel with the 4-speed auto and electric 4wd.

 

As it's done 225,000 km the suspension is pretty tired and I've got a long list of parts ordered/here to get it back to where it should be, including new KYB front struts, a set of Nolathane control arm bushes, and 35 mm raised Ironman springs (I went with Ironman as I wanted the softest lift spring I could get to maintain articulation, especially at the front). If they sag then that's what strut spacers are for, right?

 

My question is, does anyone know the longest length rear shock that can be used with the Ironman rear springs? If anyone had the length of the spring on hand I'd be much obliged (mine haven't arrived yet).

 

Currently the vehicle has Monroe 16-0423 shocks on the back. I went and flexed the truck up yesterday and took some measurements - fully flexed, the stuffed side was sitting on the bumpstop and measured 430 mm from bolt-bolt. Fully drooped, they measured 600 mm. This essentially gives me 7 inches of usable travel, with a large amount of wasted uptravel (Monroe rate them at 365 mm compressed 595 mm extended).

 

From research I have done, the best and most suitable extended-length shock would be the Procomp ES3000 326500. This is rated at 405 mm compressed and 688 mm extended, which would give me approximately 11 inches of usable travel, some 4 inches more than I currently have. I'm open to replacing the brake line if I need to (Centric p/n 15042354 apparently fits and is 4 inches longer than standard, for a Frontier).

 

What I'm most concerned about is whether or not the Ironman spring will be captive with a shock of that length. I'd rather not use spring spacers, but I would like those 11" shocks!

 

Here's a few pics of the truck. It's pretty much standard, with only a GME TX3100 UHF radio and 31x10.5r15 Goodride SL366 mud-terrain tyres currently, which fit the original alloys with no rubbing at all. It also has a JDM dealer option front skid plate, which is very sturdy (4 mm alloy with 4 mm overrunners) and has held up well to the worst that the West Coast could throw at it.

 

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Photos were taken on the Huntsbury track on the Christchurch Port Hills, New Zealand.

Edited by KiwiTerrano
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"(I went with Ironman as I wanted the softest lift spring I could get to maintain articulation, especially at the front). If they sag then that's what strut spacers are for, right?"

^ Smart! I agree.

 

 

Those springs are listed in their catalog as having a free height of 370mm.

Obviously, you need to know the distance between spring perches when your shock is fully extended to 688 mm to determine if they are long enough to remain seated when those shocks are fully extended.

 

 

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Stock Pathfinder shocks are about 15" (381mm) compressed and 24" (610mm) extended. I have found that for 2" lifted applications, the best replacement shocks for the rear are those with about a 16" compressed and 26" extended length. Rancho RS999010 or Bilstein 33-185552 work well. You may be able to get a slightly longer shock, but shocks with more extended length also tend to have a longer compressed length, and you don't want to bottom out the shock before hitting the bump stops, which could happen when articulating the axle. I ran the now-discontinued Rancho 99010 for many many years, and later I ran the Bilstein 5150 equivalent of the 33-185552. The valving on the Rancho shocks is manually adjustable, and the valving on the Bilstein is well-suited to the R50 platform.

Edited by XPLORx4
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  • 3 weeks later...

Cheers for the replies. The procomp shocks I was looking at are rated at 15.91" compressed so they should work. I'll give them a whirl I think, after taking some more measurements regarding spring length and perch heights etc.

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  • 2 months later...

Measured my Ironman springs (NISS034B/NISS035B). Fronts measured 370 mm, rears 400 mm length.

Springs are being fitted today. Will then take measurements of the mounting points and do some trigonometry to see if these procomp shocks will be too long or not.

 

However I am confident they should be fine. AC 2" lift springs are 385 mm in length, and these 35 mm Ironman lift springs are 15 mm longer. The shocks I am planning on running have roughly 25 mm more downtravel than the Rancho shocks commonly used with the AC springs, so my extra 25 mm of hypotenuse should hopefully not be too much for my extra 15 mm of spring (essentially the other side of the right angle triangle formed by the shocks and springs). If it is too long, I'll get some 15 mm spring spacers for a LR Defender to take me to a (still legal) 50 mm lift.

Edited by KiwiTerrano
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I'll be interested to see what works for you here. Remember that the measured height of the spring is the "free" measurement, meaning with no load. Though the Ironman spring has a taller free height, the spring rate is probably quite a bit softer than the AC spring, which will likely net less lift once on the truck. Staying tuned to see the progression of your Terrano. Welcome to the R50 life!

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Keen to follow the progress you make with this truck.

Did you end up doing anything to the engine in the end?

Final question, what sort of mileage do you get from a tank with your QD32?

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Keen to follow the progress you make with this truck.

Did you end up doing anything to the engine in the end?

Final question, what sort of mileage do you get from a tank with your QD32?

 

Will hopefully have answers on suspension in the next day or two. Fuel-wise, varies a bit depending on what I'm doing. Open road, ~10-11 L/100km. Around town, 11-12. Towing, I've seen up to 15 (ouch).

 

Have now driven a mate's 2.7 R50 (R3m-R), but he has a 3" downpipe and 2.5" straight exhaust. MIne has similar power until ~3000 rpm when his takes off - the lack of resistance allows the turbo to spool a lot better it seems.

 

Engine can wait, it has enough power that I'm satisfied.

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  • 3 weeks later...

Have now had a chance to fit my new shocks in the rear. They're perfect in terms of length, but the fact they can't be mounted upside down is a slight problem - first time offroad I bent the shock body on the panhard bar end... Should have gotten the invertable Bilsteins perhaps (not the Procomp ES3000 326500). However, the dent on the shock body doesn't seem to have affected their function as the ES3000 has an outer body which contains only oil, and the piston moves within a separate inner skin Time will tell.

 

When flexing down at the Waimakariri, I measured 15" travel hub to wheel arch, and I still had another 40 mm or so uptravel on the stuffed side... Great flex. Front end, I had 4" travel :D

My mate's KZJ78 Prado with a 4" lift struggled to get 10" flex with the swaybar in, and got 12" with it out in the rear. It did get 9" in the front though.

 

so, you can safely run 11" travel shocks with a compressed length of 600 mm on an R50 with 400 mm long rear springs. Just make sure they're narrow body or invertable.

 

I tell you what though, with the new suspension it's so good offroad. really makes the most of it, and the spring rates are perfect front and rear (not too stiff and not too much spring lift at the front to maintain articulation). My educated guesses were about right.

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