Maruti 800 Carb TURBO (2007 Project)


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This is a old project done sometime in 2007 -

It had just been a few months that I moved to my new apartment . My kids found new friends to play with in the neighbourhood. Soon I made friends with a family at my church (my kids already knew their kids by then). There were a lot of things in common, most importantly love for automobiles. He had some parts for a turbo build but dint quite get the time or patience to put it together. Soon (in early 2008) we decided to do a M800 carb turbo build with as little as performance parts possible and a shoe-string budget. We would meet up and spend time on the build almost every evening.

This was an old 86-87 beaten up M800 with quite a bit of rust all around. We decided to go with the 800 engine as-is without a rebuild to see how much of boost it could withstand and later maybe based on the results do a fresh rebuild. My friend also had a NOS kit he had used in the past but decided against using it along with turbo build.

1st Turbo set up

1. Small Daihatsu turbo (used)
2. AISAN Carburettor
3. Greddy (knock off) BOV
4. Ambassador MPFI fuel pump
5. DIY Mild Steel turbo manifold
6. Mild Steel - 2 inch exhaust
7. Small Hyundai intercooler
8. An Industrial pressure (vac/boost) guage
9. Mild Steel - intake plumbing
10. Mild Steel - Carb intake collector hat
11. Radiator hose quality rubber hoses*

About 2 weeks into the build we had the setup ready. I wondered how this carb would behave when boosted (the stock carb would tend to bleed from everywhere). With a few adjustment to the carb, the car started and idled fine. Took it out for the 1st test drive and soon enough faced the 1st problem – car would fall flat on its face by the time it reached 2-3psi, as though it just dint get enough fuel. The good part was that the carb was not leaking fuel from anywhere. Found some info on a similar carb and tried replumbing the vaccum and boost lines. It showed a lot of improvement and things were fine till about 7-8psi. After a few permutation and combination on jets the car was good for 10 psi, after which the fuel compensation was weak and we had not way to retard the ignition timing. Now, we had our next problem – oil being spit out through the breather pipe (partly maybe because of worn out engine/ blow by).

2nd setup

The same as 1st setup except for a fresh engine rebuild. No more spitting oil through the breather pipe. The car/engine felt much stronger and crisper than before and with further refinement to carburation the car was feeling quite strong till 12-13 psi. Soon we blew an intake rubber hose, which was replaced by a better one. On one of evening test drives on a then vacant air port link road things suddenly took a bad turn. While on boost (peaking around 14 psi) a sudden mettalic noise as though something broke free !! Quickly turned off the ignition and rolled to a halt on the road side. Had a bad feeling – wondering if the piston or con-rod broke/bend. Opened out the spark plugs to see all plugs in OK condition. Took the plug wires out and cranked the car – surprisingly, no mettalic noise. The car engine seemed to be OK. Plugged in the spark plug wires and the car cranked up and idled just fine. Just as we drove the car, got a weird feelin – NO BOOST !! Stopped the car again and upon close inspection, found a blown turbo, litterally !!! The turbo - compressor side had a narrow long crack and the compressor blade broke free through that. The shaft remaining intact in the compressor housing. Lol – No compressor blade / No BOOST !!!

Luckily we had another of the same turbo that we had picked for parts. Marked out the positions for the entire assembly, opened the turbo, swapped in the compressor wheel and slapped it back together according the positions earlier marked, hoping we would get it as close as possible. Wanted to get it balanced after this, but had no clue where to get it done though. The car ran just fine but we ran into turbo issues again with a failed turbo – oil in the intake pipe (most likely because of the DIY rebuild with DIY machined parts)

3rd setup

Now we had a slightly bigger KKK turbo, a bigger carb collector hat and a top mounted intercooler with shorter intake plumbing as compared to before. With this the car felt stronger on boost. But the main issue this far has been to get the fueling right on higher boost. I was out of town on a weekend with my family and on the Monday morning, he called me to say that a piston broke. Hmmm … Maybe another engine redo, I thought !!
In the evening he told me that while I was out of town he had used NOS while on 12-13 psi on 2 gear, which is something I had told would likely happen with NOS turbo combo on a normal M800 internals. Having said that – I should say that the humble M800/ internals can take some beating !! The next day we had the engine out to see what/what all went wrong inside. To my surprise, it was not much. The top ring land (about 1/5th of the dia had broken).

4th setup (last thus far)

It was about 6 months into our build by now, learning more - as failures, lack of success and days pass by. Got a NIKKI carb and this time used a slightly dished out/ low comp pistons for the new build. Again, had to spend sometime to get on the learning curve for the new carb but definitely quicker than last time. The result with lower comp pistons and the new carb was – the engine felt stronger on boost and reduced pinging after it was pushed beyond 14 psi. We did not have anything in place to retard ignition timing with boost/load and that has been an issue right from the time we crossed about 7 psi boost.


Besides all the above engine mods, we also changed the M-800 gear box to a M-1000 gearbox and a few mods on that. Stock shox were rebuild for a stiffer suspension. A slightly modded clutch and brake booster was also installed. We also put in a recalibrated esteem speedo console into the M-800 dash board. After all this I can say that the car felt quick and fun/scary as hell to drive.

The car was still far from perfect especially high boost fueling and ignition over 10 psi, but it was a lot of fun and a whole lot of learning. I wish I knew carbs well enough to make it behave better !!!
 
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Good work, Keep it coming and eagerly waiting to see and learn more. This is one hard DIY as well. Wonder how you manage to do all this when you have kids and all. I love DIYs myself. But after getting married I dont get the time to try anything, Even if its some mediocre small job.
 
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necessity is the mother of invention
you proved it

good on you and great work you have been doing

what happend to that piston , how did that ring land got smoked?

I think you should use forged pistons and the head (polished)
 
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Thanks guys.

I was out of town during a long weekend. And my friend rigged in the NOS setup for a test run (I had asked him not to run NOS withe new setup, to which he had agreed). He did a couple of hard pulls and a part of the top ring land gave way. Busted !!

The strange or rather surprising thing is that the Maruti 800 OEM pistons hold strong till about 1 bar of boost without any issue. This problem arose probably because of Turbo and NOS in action together - which may have overwhelmed the engine.
 
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Oh thats so sad to hear some people you just can't explain in simple language.

I agree some engine heads can take upto 1 bar. Skyline's cylinder are okay upto 18-20 psi boost, over that you need a custom head (polished)

Don't use NOS at any stage man , that is just not necessary unless your into pro drag .
Turbo should satisfy everything
 
Thread Starter #10
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Got a new firmware/software update for my Race Dynamics ECU (M800) today. Though Karthik (Race Dynamics) told me that its different from what I was running till now, it really came as a big-big surprise. The ECU allows much more control over parameters especially during "Transient load" conditions. All in all today was a great day ... the ECU software upgrade made me a happy man.
 
Thread Starter #12
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No. I dont have any software/tools to modify stock ECU. I really wish we were able access and mod the stock ECU maps like what people do to their Honda ECUs.

The only option I've heard for older suzuki ECUs is from Rhinoman (username) in UK.. I think. He was able to get get access to stock Suzuki ECU files and was also working on something like a "ROMULATOR" to modify and replace stock ECU maps. Now he sells his products/solutions on RhinoPower Ltd.

I dont personally know if its good/reliable. I guess one of us should try it out someday.
 
Thread Starter #14
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I dont know if its reliable. But, Ive heard/read good things about it and hes been digging into Suzuki ECUs for many years now. So Im sure hes reasonably good at what hes doing.

You can connect a PC/laptop to the OBD II port with the right type of Dianostic tool/cable.
Old Marutis do not work with generic OBD II diagnostic tools like ELM based scanners etc.
 
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