Hi Guys,

 

This is a bit of a random topic but hoping you guys would be able to help me out here.

 

I have a Suzuki sierra with a 5k engine in it.

 

I've got 31" tires on them at the moment and it really struggles to see 100km's.

 

Speaking with some suzuki guy's and they reckon something is playing up as the standard 1.3 litre's (G13a) can go in excess of 100 with the mods i have.

 

Running gear i have:

 

31x10.5 tyres

3.9 ratio diffs (I think)

6.1 ratio Transfer case

 

Is there any more info i need to calculate what top speed i should be getting?

 

I have done a fair few things to make the car be a bit more drivable - Carby rebuild, replace spark plugs, engine oils, GB oils, oil filter, replace air filter etc but was hoping for a bit more? am i expecting too much out of a 5k?

 

Thanks for your replies

Sorry forgot to add that i've also done an engine compression test and got 200psi of 3 cylinders and 150psi on the last cylinder.

Could this be the reason?

Anything more than a 10% difference in compression between the cylinders is a problem, that is a 25% difference, sounds like it need new rings - you've lost compression

Hi Andrew, There are other toyota powered sierra guys on here that may respond but before they do ill put in my limited knowledge....are you using the toyota gear box? my guess is yes. if this is the case then the ratios in the gearbox are what are turning your 4wd into a rock crawler. Check out the ratios of other gearboxes in the corolla range this may help. On the other hand how long have you had the conversion as it may be something related to the motor?

 

Go the suzi :D

I bought the car with the conversion already done – maybe I’ll check the engineer’s certificate later when I get home. Maybe a max of 3 years?

100% sure that it is a Toyota box but don’t know which model box it is.

 

I’m guessing there is no quick fix to get my compression back up on the one cylinder? I had a mate of mine say that it should be fine as long as the other 3 are normal… I guessing that is a bunch of b/s?

The motor itself is not chewing through oils or blowing out smoke so I'm not sure what is going on.

Try dribbling a bit of oil (like 20-30ml) into the pot with low comp and then comp test it again. That should tell you if the lack of compression is being caused by the rings or maybe a valve! If its the ring the comp should come back up a bit, if a valve it won't. :wink:

G`day mate, check out NBS4x4 website. Thats North Brisbane Suzuki 4x4 Club. Those guys have done a million conversions and I`m sure that they will be able to help you. I`ve been on a lot of trips with them and most are ready and willing to help out fellow Zook nuts.

Cheers and good luck.

p.s. you should be able to do rings and bigend bearings without pulling the engine out of the car.