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[tigers_gonads]

A friend customer of mine has dropped a vtec lump out of a type R civic in his.

It was pushing out around 220 bhp 

Talking to him about it last night, apparently he wants more power on it so he is on about strapping a supercharger onto it 

Don't know what chassis he has  :-/

IMHO, he started out with the wrong engine for forced induction.  :-/

Its not something I know that much about to be honest  :-/

Apparently you can get the Ariel Atom with the same upgrade  :-/
It's supposed to give another 100 bhp 

It's definetly a Vtec but I might have got the donor car wrong  :-/
I'm going up there for a coffee and to give him a quote for some work on friday morning so i'll have a nosey then 

[Marks DTM Calib]

Yes, Forced Induction = the need to lower static compression as a minimum....plus forged rods etc etc.....basicaly a total engine rebuild.

[Kevin Wood]

Its not something I know that much about to be honest  :-/

Apparently you can get the Ariel Atom with the same upgrade  :-/
It's supposed to give another 100 bhp 

It's definetly a Vtec but I might have got the donor car wrong  :-/
I'm going up there for a coffee and to give him a quote for some work on friday morning so i'll have a nosey then 

Well, the VTEC engines have all been optimised for the maximum power from a naturally aspirated setup, so they are high revving, high compression VVT lumps.

For forced induction you need much lower compression to safely run any significant level of boost, being able to rev it to stellar RPM isn't as important, but the bottom end needs to be strong enough to handle significantly more torque at lower RPM (to an extent these will be conflicting requirements in the design). The VVT setup probably won't be useful for forced induction and the cam profiles probably won't be ideal in the first place.

I'm not an expert on the VTEC engines but a glance at their basic spec. tells me that he'll probably be throwing more away than he's keeping if he does a proper job of supercharging it. Best to sell the engine on for someone else to enjoy and pick something else that's a better starting point, IMHO.

OR... look at where else the formula can be improved (probably more cheaply!)..

Check the intake and exhaust are flowing as freely as they can (I expect a set of throttle bodies and a tuned exhaust might well make that engine sit up and take note if not already fitted).

Check that the gearing is right for the car (with an engine as lairy as the VTEC in a light car, I suspect the average RWD gearbox from a plodder will have very inappropriate gearing).

Lose as much weight from the car as possible, etc. etc.

220BHP really shouldn't feel inadequate in what is presumably a light kit car, so it pays to consider if it's working as well as it could be. 

Not trying to pee on his chips or anything, just a few things that I'd be considering before exposing my cheque book to the sort of abuse that he's contemplating.

[aaronjb]

Yes, Forced Induction = the need to lower static compression as a minimum....plus forged rods etc etc.....basicaly a total engine rebuild.

That very much depends on the engine, though.. No idea what the static compression on the VTEC engines is, mind, I presume somewhere around 11.5:1?

The 1ZZ in the MR2 is turbocharged (up to ~12psi) and is otherwise internally standard; standard pistons, rods & bottom end. It's all good for close to 300bhp (flywheel) before a rod will exit the block - from an engine putting out ~140bhp standard..

I presume the Honda engines are more 'fragile', though.


(As for the throttle bodies - the engine should be fully built before they go on; if it's the 390 then stroked, Edelbrock heads etc etc. If I pick up a 428 then I probably won't stroke that but heads etc of course - the cast iron stock heads are only useful as boat anchors!)

[tigers_gonads]

Right, I must get my ears sorted because I got totally the wrong end of the stick 

The vtec civic was his wifes 
He looked into supercharging it but came to the same conclusion as you lads  ..............  so ............. yesterday, he traded it in for a 60 plate Alfa Guilietta 1.4 turbo with all the toys and 170 bhp 

His best toy is the kit car.

Its a Dax with a 300 bhp cossie engine 

He bought it off some bloke who builds them for a living.
Apparently it cost 25 grand too build. (very high spec / showroom finish)
My mate payed 15 grand for it with 1800 miles on the clock.


After spending 20 minutes looking round it, he said do you want to go for a spin in it 
Of course I can't be rude and say no 
So off he went to shift the Alfa of the driveway then he jumps into the PASSENGER SEAT 

I've drove some bloody quick cars in my time but nothing like this.
0-60 under 4 seconds (if you can change gear fast enough)
Geared for 150 ish mph

All this was 11 o'clock this morning ............. I still feel like someone has rammed a coat hanger (sideways) in my mouth 

I've took some pictures so if I can work out how to put them on, I will 



edit ............... his day car is a 54 plate 911 

[Kevin Wood]

Ahh. Cossie Turbo Dax Rush. Brings back some memories.

A mate of mine built with a little help from yours truly.



Used to shift nicely. A great tool for annoying bikers.

Being used to a Westfield, you had to bear in mind how wide the back end was, though.

[tigers_gonads]

tbh the thing that shocked me was not the power but the ride 

Over some bumpy roads it changed direction like a go cart but rode just like a sports saloon 

Steering was bloody heavy at slow speeds so I just went faster 
I know we have known each other a long time but I still can't believe he let me drive the thing 

[tigers_gonads]

I can't work out how to use this dropbox thingy

If someone would like to pm me a e mail address, i'll send them to you then could you  stick them on the forum for us ?

[tidla]

I can't work out how to use this dropbox thingy

If someone would like to pm me a e mail address, i'll send them to you then could you  stick them on the forum for us ?

try this site

http://photobucket.com/

upload and copy the direct link line.