I've never really got on with the MPS4S that were fitted after OEM Dunlops but now running them at 34psi has made a difference. Superpro caster bushes have been fitted up front whilst the engine was out- the caster change isn't as dramatic as other users online claim but it's there. I'm sure the Quafie diff is doing its thing too but so far, I can't single it out.
No pictures but Eibach ARBs have been fitted. No dramatic change in handling but another subtle improvement. Front is a half hour job, the rear was a right pain due to the droplinks. Ended up having to have them replaced:
Next change for the chassis is the suspension. I feel like the adjustment of the damper setting in car is a distraction and I'm always reaching for the switch to see if the car 'feels better' on road surfaces with the 3 options so I'm going for a passive setup:
The JCR inlet manifold is still to be fitted. I'm not sure it'll add anything to the power at this point but it looks too good to leave it in the box. The Radium fuel pulse damper on each rail were fouling the plenum runners so I plan to either fit an external FPD between the rails and the fuel pressure regulator or fit a FPR with a built in FPD. Either way, it's going to require a change to the fuel system- plan is to fit a return to tank system anyway. The Radium setup just now is deadheading in the fuel rails. Normal running is fine but upon initial startup the engine needs a couple of extra cranks before it fires up.
The next fitment issue with the JCR manifold is with the ATPower 72mm throttle bodies. The opening on the JCR manifold where the TB bolts onto is designed for OEM TB so is too narrow for 72mm.
A machine shop has made up adapters to fit the two together and it should work nicely:
76mm upper boost pipe > 72mm throttle body > tapering down to OE opening (~63mm)
Which leads to the next fitment issue- I instructed the engine builder to weld a boss into the upper boost pipe for the air temperature sensor however they instead tapped the OEM inlet manifold and fitted the sensor there. Not a huge problem but I'll need to have the upper boost pipes modified again to accommodate the sensor and perhaps also have the path changed slightly to compensate for the additional angle introduced with the throttle body adapter.
And finally, the mounting plate where the JCR manifold attaches to the cylinder heads is thinner then OEM manifold so its likely that the rails will need spaced out to ensure a proper injector seal is achieved but will assess upon fitting.
When I was fitting the Eibach ARBs I noticed the rear subframe and the brackets in particular were showing signs of corrosion.
The subframe was just cosmetic but I treated it and the control arms with Bilt Hamber Hydrate 80 as a stop gap until I get the transmission built where it'll stripped and painted/powdercoated then have the underside treated with Dinitrol, Bilt Hamber or Lanoguard.
The brackets for the undertrays were beyond saving. I searched and asked opinions and whilst a few people made their own most go for Kaizer brackets.
£183 for some sheet steel is a bit much even with GTR tax added but the product fits well and I couldn't make better myself so ponied up and fitted them last weekend.
Most of the OE rivets were missing and what remained turned to dust when I started to drill them out so fitting only took a couple of hours max including getting the car on stands and getting the trays off.
All 5 brackets were rotten with that second picture being the worst- there was no steel left there, all rust.
The car doesn't get driven in winter much although it has done; I can only think a combination of wet salted roads and maybe galvanic corrosion (stainless bolts with mild steel OE brackets) accelerated the rot. This is a MY17 car just over 4 years old.