WET SUMP OIL CONTROL
The sumps as fitted to most XU9 engines (8V and 16V) have no oil control. Their use on a serious track day will result in fatal engine damage, due to oil surge. The only exception, is the baffled sump as fitted to late 309 GTi16V’s. These sumps have a trap door baffle sump similar the later XU10 sumps. These 309 sumps are very rare however, but were used on the factory Mi16’s raced at Bathurst in the early ‘90’s. Better alternatives are now available.
The first stage in oil XU9 oil control is to copy the XU10 sump. Trap door baffles are custom made to fit either the 8V alloy A/C sump or the finned Mi16 sump.
You can either buy the trap door baffle as a kit, and fit it yourself. Or purchase the completed sump on an exchange basis.
Both options also include a pump baffle which attaches to the oil pump via four existing M6 bolts.
Three different shape pump baffles are available:
- standard Mi16 sump
- standard 8V A/C alloy sump
- 8V A/C or XU10 sump with 15mm extension
A better option is to increase the capacity, lower the pickup and fit baffles as above. Two sumps can be used for this purpose, either the XU10 sumps or the 8V A/C alloy sumps as fitted to the 75kW DFZ engine.
My preference is the 8V sump, as the XU10 sump already has a trap door baffle wall fitted, which doesn’t extend the full height of the sump (see picture right). The 8V sump however, is exactly the same height but fully open, and thus can be fitted with a wall that extends to the full height of the sump.
Additional capacity is good for two reasons. Firstly, more oil is available to keep the pickup covered longer during extreme corning, and secondly, the additional oil carries heat away from the engine more effectively. Increasing oil capacity is the first stage in keeping any hydraulic system cooler.
The additional capacity comes from fitting an XU9 sump spacer to one of these sumps. The additional 15mm in thickness of the spacer, increases the oil capacity to approx. 6.5L. The final capacity depends on oil cooler, lines, remote filter etc. To make use of the additional capacity however, the pickup must be extended deeper into the sump. I offer an aluminium extension ring, machined on a CNC mill, which is welded to the original pickup. Socket headed cap screws are used to retain the screen assembly to the new extension. The extension is available either as a kit or on exchange pickup basis.
As all XU engines are tilted 30 degrees, the additional 15mm spacer theoretically only results in 13mm of overall extra depth. However, it's actually better than this at 8mm, as there are no fins on an XU10 or 8V A/C sump.
The final stage in wet sump oil control, is to fit a windage tray, in addition to the deeper sump above. The XU10J4 (S16 and Mi16 11/’93 onwards) and the XU10J4RS (GTi6) engines, have a windage tray fitted as standard. This is achieved by attaching the windage tray to four extended mains cap bolts. Other XU10 engines can easily be upgraded to this specification by purchasing the windage tray and four mains cap bolts from Peugeot spare parts suppliers. At time of writing, the windage tray was approx. AUS$40 and the mains bolts $25 each.
Fitting a windage tray to the alloy XU9 blocks is a little more difficult, but not impossible. To achieve this goal I cut and mill the two ribs from an XU9 sump spacer. I then weld in three new ribs, which serve two purposes. Firstly, they brace the bottom end more effectively, and secondly they provide attaching locations for the XU10 windage tray. The windage tray also requires a small modification to clear the oil tube, but this is all included in the packaged price.
Because XU9 sump spacers are rare in Australia, I can only offer this upgrade on an exchange basis, or sell the new ribs individually on a DIY basis.
Windage Tray - Peugeot Part #1047 17
Extended Mains Bolts - Peugeot Part #0132 43 (4 required)
OTHER IMPORTANT GOODIES
The later XU10 engines also have several other differences which help to overcome oil starvation problems. All of these parts are available from Peugeot at time of writing.
2L Oil Pump Spring
This is called a 6 Bar spring which provides increased oil pressure over the original 1.9L spring. This spring will give 65psi @ 7000 RPM, just about perfect for achieving 10 psi per 1000 RPM. Beware that the same spring is sold by others for far more.
Peugeot Part # 1157 11
2L 26 Tooth sprocket
The XU10J4, as fitted to Mi16 and S16, has a 26 tooth drive sprocket. The 1.9L engines only have a 22T sprocket. As the oil pumps have identical sprockets, this larger sprocket spins the pump faster, increasing flow and pressure at lower revs. A 52 link chain must be fitted. Avoid cheap chains which have a joining link. They will whip and the joiner will hit the timing case. Use only OEM or Reynolds chain.
Peugeot Part # 0513 54
Both the 2L spring and 26T sprocket should be treated as mandatory for any XU rebuild.
2L Chain Guard
The chain guard attaches by two M6 screws to the 2L pump. It can not be fitted to a 1.9L pump as there are no mounting holes.
Peugeot Part # 1047 08
WET SUMP SUMMARY
If you've done all of the above, use quality 10W-60 racing oil and still get excessive oil surge, there is only one remedy - a dry sump. The products above have been successfully tested in 205 race cars running semi-slicks. None of the cars with this specification have experienced bearing failure. That's not to say you won't. You might be a better driver, in a better car and can generate more G forces.
Also important, is to fit a reliable oil pressure light. Buy an adjustable falling oil pressure (Hobbs) switch and set it to 25psi. You may not see a needle move in a corner but you will see a big red light.
Oil pressure will still fluctuate with all of the above. Hopefully not too much. The only way to get a constant 70psi is to fit a dry sump.