Honda City VTEC High Compression build.*UPDATE* And she runs!!

[pranavt]

So this is a build that was undertaken for a very good friend of mine. The original plan was to replace a blown headgasket over the weekend; but when the head was lifted, I didn't have the courage to just put a new gasket on and bolt the head back on. The sleeves seemed to have quite a few scratches and there was a huge build-up of black oil deposits in the head because the previous owner probably hated this car and didn't bother to service it.

The engine was taken out. The block was given a fresh 75.5mm bore. Since the stock VTEC shows its age now, there was no point in spending a good amount of money to take it back to stock condition. So a decision was taken to bump up the CR and do a budget high-comp build correctly.

Anyways, the new specs:

75.5mm bore
Stock 84.5mm stroke
New high compression pistons with matching connecting rods
A mild-moderate port and polish job done by me.
Stock cam and cam gear
AEM conical filter and intake
Honda standalone ECU tuned by me.

The resultant static CR stands at 10.6:1, as opposed to whatever the stock VTEC offered with its pistons. The new pistons sit flush with the deck. No need to use double head gaskets, shave the pistons or use deck plates LOL

The port job is currently in progress and should be completed during the next week if I have time to go away from my own car that is being prepped for the drags in April. The porting is being done keeping in mind certain facts about Mumbai roads and the need to preserve low-end torque while still flowing well enough to compliment the higher compression nature of the engine. The rest of the internals are kept stock currently because my idea was to build a reliable high-comp motor within a small budget.

However, the groundwork has been done along with a solid bottom end that is enough to make good power in NA which is what the friend in question desires to stick with for now. The next "stage", if you will, should involve a better flowing intake manifold, a nice cam suitable for the street and better headers to start with.

The engine has been built pretty much and should be bolted on by the next weekend. The running in will start after that and will last for around 1000 km after which the standalone will be street tuned with my wideband and knock sensing hardware and reading spark plugs. Until then, a revlimit of around 3k RPM will be set and a conservative fuel/ign map will be created to make sure the run-in goes well. The ECU will be tuned once the running in is complete and should allow the engine to run properly on pump fuel. A small part of the fuel/ign map will be reserved for lean-burn which will allow the engine to cruise at around 2-2.5K RPM/100-120 kph while returning a mileage of around 18-20kmpl. This is being done because the car is regularly taken on outstation trips where the highways are good enough to cruise at said RPMs for most of the journey. I'm very much looking forward to the tuning stage since that's when the motor will show its real character.

Pictures of the engine internals are with my friend and I'll be asking him to either post here (he's a member too) or send them over to me.

For now, a money shot taken a few hours ago.



First startup video will be posted probably during the next weekend. If all goes well, the car should be taking part in the drags next time around.

[1self]

Nice! Getting the engine to run on normal pump fuel (not premium) will require some ignition retard though. More pics please!

[moralfibre]

Pranav, I've seen your VTEC build up thread and have no doubt that this one would be as successful. Do keep us posted on the progress.

My best wishes.

[pranavt]

Thanks

Originally Posted by 1self

Nice! Getting the engine to run on normal pump fuel (not premium) will require some ignition retard though. More pics please!

Since we get higher octane fuel than what was available when the car was released, the timing would actually have to be advanced since higher octane burns slower. The raise in compression will probably offset that small advancement that would have to be done. But a difference in engine internals/characteristics is going to have a different MBT. Who knows, I'll probably still end up advancing the timing because of the tricks I plan to employ for the lean burn

Some more pics

The block, crank, girdle and other peripherals. The bottom end was in great condition actually, a stark contrast to the condition of the head which you will see below.


The rocker assembly freshly taken out of the head


After cleaning


The new stuff


New OE head gasket from Honda USA


The ECU, prepped and ready to do duty


The block being honed after oversizing to 75.5


More pics will come later.

[Mpower]

Originally Posted by pranavt

The block being honed after oversizing to 75.5.

How did you oversize it, drilling?

The CR increase could have been achieved by shaving the head right? Did you really need new pistons?

[heavy_foot]

He did mention that the sleeves had some scratches and so he gave a fresh bore. Nice thread!

[pranavt]

Originally Posted by Mpower

How did you oversize it, drilling?

The CR increase could have been achieved by shaving the head right? Did you really need new pistons?

Didn't want to mess with the head in case he wanted to go FI later on. Plus if the cam was upgraded in the future, didn't want to have worries about piston-to-valve contact. And shaving the head is a hit-or-miss job depending on the mood of the labourer. I've got a small coolant leak from the exhaust side of the head because the surface wasn't perfectly flat after shaving which will require me to do a better job on CNC equipment whenever I lift my engine's head. I didn't want to have the same issue with a client's head, good friend or not.

Stock sleeves weren't looking good, and doing a fresh hone to get a crosshatch would just increase the p2w clearance increasing oil consumption.

@heavy_foot: Thanks

[GTO]

Congratulations Pranav! This is a car that's stupendously fun-to-drive in stock form itself. I can only imagine what she's like once on the road. For the lesser technically inclined amongst us:

- What's the expected output (BHP & torque)?

- Target 0 - 100 time? 1/4 time?

- Revv limit after running-in is complete? 8,000?

- Any mods to the suspension? The stock components had their work cut out with 106 BHP as it is.

- Cost of mods?

[pranavt]

Thanks.

1 - No idea. I am unaware of a similar build done in India, if any, and what HP they ended up making. A few who have tried have ended up with pistons sticking 3mm out of the block and have ended up using multiple head gaskets and shaving piston tops off. Plus there is the debate about the accuracy of the Mumbai dyno wrt the exaggerated figures when compared to the Bangalore dyno. Will do a dynorun whenever the running in is done.

2 - Targeting a 14.8+ second 1/4 mile time in race trim (lightened, drag slicks, etc)

3 - 7100 with the stock cam. If/when the cam and valvesprings are upgraded, the revlimit will be raised until it stops making power. It's a complete street build with no intentions of actually any competitive racing. I want him to take a shot at a dragstrip just to show what can be done with a reliable high-comp motor on a budget without having to apply Indian jugaad methods.

4 - None yet. He'll probably opt for Konis with Ground Control springs once the budget is high enough.

5 - Around 75-80k I believe, give or take a few grand.

[kutlee]

good build pranav. Good to see brand new pistons in box. Why is that conversion harness? have you chipped the stock ECU?

[sgiitk]

Originally Posted by 1self

Nice! Getting the engine to run on normal pump fuel (not premium) will require some ignition retard though. More pics please!

Today regular is 91RON. They are selling the so called Premium which is Premium only for Euro/BS2 (BS3 & 4 specify 95RON for Premium) at 93RON. Of course you can pay Rs.10 per litre extra for 97RON if you can get it in your city.

[alpha1]

PranavT: gotta keep you in mind when my vtec become old and ailing - I guess it is already in process and requires a steroid shot

Will follow this thread.

[konjaril]

Pranavt, kudos to you man. I have been following your earlier build on the vtech and this too is turning out to be very promising. i am visiting your thread almost everyday now for updates. all the best for your endevours man.

On a lighter note i would really appretiate some pointers from you when i get around working on my engine.

[ssjr0498]

Pranav,

When you say that a few have tried, are you reffering to Venkat's (blacmagic) build? ( For other's you could read that here http(colon)(double slash) t i n y u r l (dot) com (slash) 4hx57j8)
If that is what you want to compare your build with then you have a serious case of tunnel vision.

Does one really need all this, just to do a 14.8 sec run?? For starters! This car is well set to do that: [COLOR=#0000ff]http://www.team-bhp.com/forum/modifications-accessories/95684-v-box-upda te-my-honda-city-vtec-0-100-kph-7-47-secs.html[/COLOR]. I have personally witnessed the build of this car and it is running way less compression that what you have mentioned. It has bone stock vtec pistons and zero lightning, its a daily drive for this friend of mine and he has clocked more than 5k kms after the head was opened! All of the above plus a 16-17kmpl mileage

Pranav, I have been following your threads on tbhp from the days you picked up your vtec. It is really nice to see you doing stuff yourself, but it looks like a lot has changed ever since. You used to be one of those who shared information and wanted more of it!! Now you are one of those who know it all and look down on others!!

Anyway, I wish you and your friend the best of luck with this build.

Cheers
Shrey


Disclaimer: This criticism is meant to be constructive. Please dont take it the wrong way.

Originally Posted by pranavt

Thanks.

1 - No idea. I am unaware of a similar build done in India, if any, and what HP they ended up making. A few who have tried have ended up with pistons sticking 3mm out of the block and have ended up using multiple head gaskets and shaving piston tops off. Plus there is the debate about the accuracy of the Mumbai dyno wrt the exaggerated figures when compared to the Bangalore dyno. Will do a dynorun whenever the running in is done.

2 - Targeting a 14.8+ second 1/4 mile time in race trim (lightened, drag slicks, etc)

3 - 7100 with the stock cam. If/when the cam and valvesprings are upgraded, the revlimit will be raised until it stops making power. It's a complete street build with no intentions of actually any competitive racing. I want him to take a shot at a dragstrip just to show what can be done with a reliable high-comp motor on a budget without having to apply Indian jugaad methods.

[pranavt]

@alpha1, konjaril: Thanks!

Originally Posted by kutlee

good build pranav. Good to see brand new pistons in box. Why is that conversion harness? have you chipped the stock ECU?

Thanks. Chipped an OBD1 Honda ECU, which is why the conversion harness. Our cars have an OBD2B harness which requires conversion.

Originally Posted by ssjr0498

Pranav,

When you say that a few have tried, are you reffering to Venkat's (blacmagic) build? ( For other's you could read that here http(colon)(double slash) t i n y u r l (dot) com (slash) 4hx57j8)
If that is what you want to compare your build with then you have a serious case of tunnel vision.

Thank you for the concern, but I've seen quite a few of these builds, not just one. What was funny about his was the kind of arrogance shown by the tuner towards his own client. My build won't be compared to his, I assure you.

Originally Posted by ssjr0498

Does one really need all this, just to do a 14.8 sec run?? For starters! This car is well set to do that: [COLOR=#0000ff]http://www.team-bhp.com/forum/modifications-accessories/95684-v-box-upda te-my-honda-city-vtec-0-100-kph-7-47-secs.html[/COLOR]. I have personally witnessed the build of this car and it is running way less compression that what you have mentioned. It has bone stock vtec pistons and zero lightning, its a daily drive for this friend of mine and he has clocked more than 5k kms after the head was opened! All of the above plus a 16-17kmpl mileage

And you honestly didn't think I was targetting a lowly 14.8 with drag slicks and lightening, were you?

Originally Posted by ssjr0498

Pranav, I have been following your threads on tbhp from the days you picked up your vtec. It is really nice to see you doing stuff yourself, but it looks like a lot has changed ever since. You used to be one of those who shared information and wanted more of it!! Now you are one of those who know it all and look down on others!!

And it's funny to insinuate that I'm being secretive about my build. I'm posting pictures of the whole build, listing what parts I'm using without needlessly putting "custom" in front of every part I list, and you accuse me of something that is very much unlike my belief. I'm hurt. LOL.