The AVO silicone intake manifold connector replaces the original rubber item (no.14 marked in red square) that joins the airbox to the throttle body.
The silicone connector seems like it has a slightly larger bore at the bend, and with smooth bore till the butterfly which should reduce the turbulence and improve the airflow into the manifold. The OEM rubber type has couple of ribbed flex humps in it which helps to tilt the airbox up whilst changing or cleaning air filter. The only problem I had with the silicone connector is that since it doesn't have the flex ribs the airbox lid will not open wide for easy filter replacement or cleaning but it still opens just enough to take out/insert the filter but with a bit of difficulty.
The additional benefit I see with the silicone connector is that the IAT sensor and the clean air line (for the block) fits much tighter to the connector. This means they would be sealed better without any chance of dust getting past it. While I do not know if all stock connectors let in dust through the IAT sensor bung mine did infact! It was an accidental discovery one day when I was removing the stock airbox that I noticed fine dust ingress into the rubber connector.
Finger wipe (you can see it in the photo) confirmed that it was indeed fine dust and once confirmed I opened and checked the top half (clean side) of the airbox but no dust there and it was clean. When I observed the dust pattern on the connector more closely it was clear that it entered through the sensor bung fitting because there was no traces of it before the bung on the same connector.
I wonder how or why this happened as neither the sensor nor the rubber connector was fiddled with in the past. The sensor is a snap fit on its bung on the rubber connector, no clamp is used or needed. So why did it let in fine dust? Maybe the particular piece was faulty or someone fiddled with it, I wouldn't know.
Anyway with the silicone connector this is not an issue anymore as the bung where IAT sensor plug into is pretty tight and it did need some silicone grease to get the sensor to slide in with force. One thing is sure no dust is getting past and it is the same with the clean air feed line for the block.
I just thought that I should complete this and put this in here on the blog as it has been a draft since far too long. I now run the AFE GT airbox but I am keeping the AVO silicone connector for the day I might change to stock.
I had no intention to spend big bucks on a set of imported rubber bump stops for the Jimny. What's the point its just rubber something else should fit?
So with that ideology and with a limited search for one in the market found the Alto's rear bump stops (part no 42251M75F10) could be a suitable alternative. It was and along with the spring change this was put in. Its about half an inch longer than the stock, give or take.
I was not really happy with it because the first segment was hollow. Well, that is kind of good makes it sort of dual stage bump stops but may be a bit too soft in the running and are not pointy like the rear. I like pointy. Said a great man in 2012.
Against my wishes i decided to import a set of bump stops with a plan in my mind. Jimnybits 25mm bump stops were chosen and they come with cone type (progressive) rubber buffer. The plan was simple I wouldn't use the supplied bump rubbers but intended to use the Jimny's original rear bump stops in the front.
It wasn't a straight swap, never thought it would be as it isn't advertised like that. The threading on the aluminium bushing is M10x1.5. The threading on the OE Jimny rear bump stops are M10x1.25. The long stud supplied with the Jimnybits aluminium bump stop bush is an M10x1.5, this is required to mount the aluminium bushing on to the vehicle.
What now needs to be done is to make the lower part (about 1.5cm) of the thread on the bushing M10x1.25 and leave the rest as is. So the lower part of the bushing can take the OEM Jimny rear bump stop and the top the M10x1.5 stud supplied for installation.
Sensible thing to do is to drill out the section of the thread that needs to be re done and do a helicoil insert. This is how it should be done, can't tap a coarse thread to fine. But that isn't how I done. I took the M10x1.25 tap and ran it through the coarse thread till required length to cut new fine threads within that coarse thread.
This seemed to work, the bump stop screws in smooth and fits tight all right. Its a bump stop, all it needs to do is hold on and don't fall off. Guess this is good enough for that. If and when the rubber engages with the axle the shock is transmitted through the metal base to the aluminium bushing and not the threads. Think I will a add a drop of blue Loctite to prevent it from any accidental loosening.
The stock Jimny bump stop seems to be approximately 60mm length. Not pictured but the Alto rear bump stop is about 10-15mm longer give or take couple of mm's. The Jimnybits 25mm extended bump stop (rubber and aluminium bush combined) is 80mm which seems about right. My hybrid bump stop (Jimnybits aluminium bush with Jimny OE rear bump stop) is about 100mm. It doesn't mean that suspension travel sees a hard stop at the new length, being conical these are progressive bump stops there is more give than a block type bump stop.
So now I have nice pointy bump stop with means to go longer (wouldn't be necessary) and easily replaceable, both OEM and both locally, if I need to in future. Being Maruti it is a lot easier and cheaper to buy the OEM bump stops than to try and source any universal type bump stop rubbers which has these M10x1.5 threads.
There is no need to import the bush either if one can do the legwork and follow up. Any lathe workshop would be able to machine a set for you easily with the correct thread. I would have done so in the past.
Why?
The compressed length of Dobinson IMS at the front is ~395mm and the compressed length of stock shock absorber is ~380mm (as given on Team Ghetto Racing, who is a friend). I haven't measured at what compression length of stock shocks the axle engages the stock bump stops. But I assume the stock bump stop length is kept as is by Suzuki to work with stock shocks to engage the axle before OE shock bottoms out.
The Dobinson IMS bottoms out in compression 15mm before the stock shocks does. This could mean the stock bump stop may or may not engage the axle before the IMS bottoms out internally in compression. If it bottoms out internally before hitting the external bump stops it could damage the shocks over time. I don't think the internal bump stops (if there is any) will be up take the pounding. In my opinion it is wise to extend the front bump stop by 15 mm to save the IMS from bottoming out internally.
The hybrid bump stops I have here for my Jimny they are about 40mm longer but this is not required and will limit the suspension up travel so is not recommended. The first solution would be enough, i.e., the Alto's rear bump stop for Jimny's front.
A gas charged monotube shock absorber is a single tubular structure holding the oil, a shaft with piston/valve, a free floating separator piston, and a gas chamber. The piston rides up and down the tube in the oil and further down tube there is free floating piston suspended as a separator. The job of this piston is to separate the monotube body into two halves - one containing the oil and piston and the other containing high pressure nitrogen gas. The monotube suspension was pioneered by Bilstein.
The function of the high pressure nitrogen gas is to apply pressure on the gas by means of the floating piston to avoid cavitation. If the oil is aerated the damping properties of the shock absorbers change as the rate with which the piston pushes the now aerated oil through the valve body. Applying a constant pressure on the fluid mitigates cavitation and the shock provides a consistent damping.
The other type of shock absorber is a twin tube and each have their own pros and cons. Twin tubes usually have linear valving and the gas pressures, if gas charged, are very very low.
If monotubes were pioneered by Bilstein why does a Dobinson IMS Monotube ride much better than an equivalent Bilstein Monotube? Two reasons - type of valving in mass market Bilstein monotubes and gas pressure.
Valving
All Bilstein shocks listed above have digressive damping, stiff at lower (piston) speeds and they ease up at higher speeds. But a sudden large impact on less than perfect road will jolt the vehicle and have experienced this many times on the roads here. Good for track and circuit.
Dobinson IMS shocks have a progressive damping curve, not as stiff at slower speeds and gets progressively tighter as speed increases. Good at low vehicle speeds and sudden impacts as one would expect on un sealed roads.
Gas Pressure
Both Bilstein and Dobinson IMS are monotube shock absorbers with internal reservoirs for oil and high pressure gas separated by a free floating piston. The Dobinsons IMS has a recommended fill pressure of 150PSI of Nitrogen. Bilstein holds a higher pressure N2 charge in their internal reservoir monotubes with recommended fill pressure between 180PSI and 200PSI and with a factory fill pressure at 200PSI. The Bilstein is at a minimum 30PSI to a maximum 50PSI higher pressure compared to the Dobinson IMS. This higher internal gas pressure in a Bilstein acts on the piston shaft giving it a gas spring effect and a static preload. Lower the gas pressure less the static preload.
A question asked frequently: Why does my car sit higher after I put a set of Bilstein monotube shocks (on stock springs)? Ans: High gas pressure.
Especially true if the vehicle was previously on a set of any low gas pressure or hydraulic shocks which were replaced with a set of Bilstein monotubes. The high gas pressure adds higher static preload to the initial weight needed to get the shaft moving. This combined with the spring rate adds to the total suspension preload at rest and at lower speeds. The effect of gas spring preload is more at low piston speeds and weans off at higher piston speed.
I have used Bilstein monotubes in two of my own vehicles, an Octavia RS Mk1 with stock and VW OE sport springs and in an Innova Crysta 2.8 Diesel with stock and Eibach lowering springs. Also had a friend's VW Vento 1.6TDI with me for many months (when he left the country) which had a B12 coil over kit. Although the B12 coilover was supplied with springs as a kit, it rode very similar to the other two. Not pleasant on our less than perfect roads, except for the Crysta.
Run off the mill Bilstein monotubes including the B12 coilover rode harsh except for the one I put in the Crysta. It was well behaved because the set was made for the previous Innova and the Innova Crysta I put it in weighed a good 200Kg more than the old Innova. This additional weight had a calming effect on the Bilstein's gas spring at low piston speeds.
Rebuildable?
Dobinson IMS is rebuildable by design and they have a rebuild kit available for the monotubes, they have a gas port to let out gas pressure and charge it post rebuild.
Bilstein supply all the minor and major internal parts as spare parts for their shock absorbers. The rebuild process of the Bilstein is a bit more involved because they have not included a gas port in their shock body. So First a hole needs to be precision drilled at a specific location to let out gas pressure and then use a high pressure Schrader valve (supplied as spare by Bilstein) installed in the shock body to charge the shock.
Both can be revalved during the process of rebuild.
Is there a better way that I could have put this?
I wish, watch the video this is what I wanted to convey in this blog entry about gas pressure. Also read the comments.
