[SkIpAi]

Howdy!

Got a 2000 JX Jimny with a 2" KS lift kit. Looking at getting some MT's for it but unsure as to what size tyre to get. If I need to change rims what offset is best? Looking at sunraysia style rims if I need to change em.
Even considering going to 16" rims for more options.

215, 235s? What will fit?

Cheers

[lordviper556]

your better off staying with a 15" rim size, i think most ppl on here run 15" rims and you can get most tyres in zook sizes.

215's will fit with ease but im not sure how the 235's will go.

[SkIpAi]

Thanks mate. Just ordered a set of 235s :-/ on black sunies. I have shock relocation brackets on the back so the loss of 30mm of up travel will hopefully help avoid scrubbing.

Anyone know if I will need to trim inner gaurds ect?

Cheers

[lordviper556]

i had to trim a fair bit to fit the 30's on mine so u may need to trim a bit as well. should look good tho

[shep]

A mate has 235/75/15 on his jimny and they scrub badly

[zooky08]

You will need to trim a fair bit. I did shit all trimming for my thirtys for 3" lift. Most of the trimming was don't to my arb bar. Ran 215 fine with no scrubbing with 40mm lift.

[SkIpAi]

Where is the best place to trim in preparation of the bigger tyres?

When I get the tape out I really start to doubt they will fit without at least trimming the outer plastic flare by a minimum of 15 to allow up travel?

Any thoughts would be much appreciated!

Cheers

[SkIpAi]

Photo moved to avoid image heavy thread

[zukenutter]

If you bought neg offset rims they'll scrub pretty bad. If you were to use the stock rims you'll only need minor trimming.
Also depends on your lift, some 2" lifts are 40mm and some are 50-60mm. 40mm will scrub heaps with 235s on either rim.

[SkIpAi]

See that 25mm flat spot on the wheel arches? I just cut them off and cut the inner guard to match. Hopefully this will help...

When I get the tyres and fix all scrubbing issues I will line the fresh edge with rubber flare.

thoughts?



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[SkIpAi]

What are the options for lockers with these? I had a ARB air locker in my 07' triton but would like to avoid the expense as this is just a toy more then anything...

Cheers

[suzooky87]

Take those stickers off and it will go anywhere.............

[Bugsta]

Nothing beats Air lockers IMO.

[SkIpAi]

Had the good ol oil leak on my tritons locker...

[monley]

I see your in Mandurah mate, if u want to try on my 235s shot me a PM. Air lockers are great when they work...i reckon they are great...just not when you get ARB to fit them

[SkIpAi]

Getting them on Monday so I will have to make them fit lol. Thanks for the offer though!

What suspension you running?

Whats the go with after market exhaust systems for the jimny? Seen extractors but no complete systems? Anyone point me in the right direction?

[monley]

Custom exhaust from the headers back. Any exhaust shop should be able to make you up a system. I did my own system cus I wanted it done right

[SkIpAi]

Keen on making another? Lol

[Bugsta]

Don't be talked into anything bigger than a 2". I approached Mac's Mufflers in Brendale and they said "Yeah we'll put a 2.1/4" on for you. I questioned it remembering that my 3L Holden had 2". They said "Nah, It'll be perfect". I also asked that they put on a resonator. Even after they did it I questioned again (Response - It'll be good). I drove away thinking Jeez this thing is noisy as... they didn't put a resonator on so I had to go back and get them to do it. Well, It just didn't have the power down low and everyone else I talked to confirmed it was just too big. I went to Ultimate Performance months later and got it done properly. Has been great since

[SkIpAi]

Yeah I believe there would have to be some kind of back pressure. Unlike a turbo charged engine which benifits from getting rid of all exhaustas fast as possible.

Cheers

[Gwagensteve]

No. This is a misrepresentation of how an exhaust works. Downstream of the collector of an extractor, no amount of back pressure is helpful. The design of the extractors provides the scavenging required to help evacuate the cylinder. Scavenging is what builds power/torque, not back pressure.

To some extent, the engine's torque curve can be tuned by the length of the primary or secondary tubes of an extractor, but once you've passed the collector, it's all over.

Lets say the collector is 2" and the exhaust needs to be 2.5m long. Let's say you ran 2.5m of 2" pipe after the extractor collector as the baseline. By your logic, if you added mufflers, or reduced the pipe diameter from 2" down to, say, 1.75" you would add power or torque? No. Power will be lost.

There is some evidence that changing the length of pipe *at collector diameter* to the end of the exhaust can tune the power delivery, but not significantly, and in the case of a car that needs to meet some sort of noise limit, it's not really relevant - there's going to be some length of pipe after the collector.

This is not necessarily the case with stock manifolds, although EFI suzuki exhaust manifolds are quite well designed (from a flow perspective) Put a 2.5" exhaust on the end of a stock manifold and the car may well loose power. Neck up to 2.5" after the collector of an extractor and the car won't loose power, it will just get fawking noisy.

I'll add that with old school carby engines, it is quite possible that a car will run poorly if back pressure strays too far from stock, but only because the car may well lean out because its scavenging better than the manufacturer designed. In extreme cases, the car might no even idle.

Steve.

[alien]

i thought the point of keeping the exhaust smaller was to keep the gas flowing faster? ie: expanding to a bigger area keeps the gas in longer allowing it to cool down and causing more back pressure than a smaller diameter (within reason) that allows constant flow? something like that anyway...

i can say for sure that my 1.3L carby engine ran AWESOME with a 1.5" pipe... but when i went 1.6l carby the 1.5 was "ok" until i went to 2" pipe - the torque difference was VERY noticeable. What's also worth noting is that i changed the cat converter and muffler to 2" as well - a lot of dodgy buggers recycle those 2 components essentially restricting it back down again.

[SkIpAi]

You learn somthing new every day!

Thanks steve

[SkIpAi]

Ok have an issue I think... Driving it this morning, I noticed that when at idle it has a bit of a mis. Its not consistant (last for maybe 10 secs) but the car shunts abit. No sound.

Any ideas what this could be?

Also I think I need a RTC steering damper as she bump steers alot now.

Cheers

[Gwagensteve]

alien wrote:

i thought the point of keeping the exhaust smaller was to keep the gas flowing faster? ie: expanding to a bigger area keeps the gas in longer allowing it to cool down and causing more back pressure than a smaller diameter (within reason) that allows constant flow? something like that anyway...

i can say for sure that my 1.3L carby engine ran AWESOME with a 1.5" pipe... but when i went 1.6l carby the 1.5 was "ok" until i went to 2" pipe - the torque difference was VERY noticeable. What's also worth noting is that i changed the cat converter and muffler to 2" as well - a lot of dodgy buggers recycle those 2 components essentially restricting it back down again.

Not really. as the exhaust cools it contracts so pressure is reduced. The gas will slow, but that doesn't mean it's adding back pressure due to the velocity change - it's slowing because it's contracting as it cools. It's quite possible to have a smaller tailpipe than the collector diameter and the gas speed will remain the same all the way along the pipe, but that's needlessly complex I don't think there's any evidence this will have any effect on power as it's so far from the collector.

The key to your point about changing engine and exhaust size is that you've increased capacity so, assuming the same efficiency, you've added about 20% to the amount of exhaust gas the car needs to flow, so whilst 1.5" might be OK for a 1.3, it is unlikely to be optimal with a 1.6.

Steve.

[SkIpAi]

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They dont scrub during normal driving (full lock both ways). I will flex it up tomorrow and see where else needs to be trimmed.

Cheers