91 Celica Gt

[piddiuk]

hi to all of you, as i'm new and know naff all about tuning or modifying cars i thought i would turn to people who may know how. basically i've got a celica gt 1991( all looking like a gt4 to me with the bodykit etc) however i wish to know how i can upgrade the power as i'm greedy and wish for more.is there chips i can buy etc ? or any other sort of performance enhancers ?

[celsteve]

Hi and welcome. Well I know naff all about Gen 5s but I suppose the old decat, exhaust and air filter are good for starters. Stick around and there will be somebody to help you soon, we have a man here who really knows his Gen 5s and hopefully he'll stop by soon.

[Dan_Q]

Hi There,

I can give a bit of info until the gen5 expert comes along......

If you want to stick with the GT (the cheapest option is to trade for a GT4) then there are a few things you can do.

As mentioned above an exhaust can open them up a bit, even if its just the back box- the standard manifold is quite freeflowing and already a 4-2-1, and the centre section is not very restrictive. The backbox is heaviliy silenced and therefore weighs a ton, just changing this for a straight through or a semi silenced item can open up the revs a bit. Be warned though- I used to have a straight through and it was deafining- it also lost some mid range torque, but when wound up it revved nice and hard. Off the shelf units are mongoose, blueflame and if you can find anywhere who still has one in stock a scorpion- thats now discontinued.

If your car is an import then a decat will also help- be careful though as some can create a "rasp" at 3-3500rpm which most people dislike. If its a UK model then at 1991 vintage it will already be a catless exhaust.

Intakes its just like any other car- open cones sound awesome and increase throttle response, although supper from sucking in heat. Drop in filters are quieter but increase flow and i would assume throttle response- I have read about some people drilling the airbox to good effect, but never tried it myself. As it sounds like you have a GT4 bonnet, and its an ATA one (not carlos sainz / rc) then I believe you can flip the side vets around to duct air into instead of out of the engine bay- this may help if you decide to go for a cone.

as far as "chips" go, there is a couple of options. Superchips produce the "ICON" which is a piggy back ignition controller- this comes with a more agressive base map and is re-mappable to your engine. I have one which runs the basemap at current, its OK but not worth the cost unless you have it set up on a rolling road. I know of someone who has had theirs setup correctly, and just having the map tweaked gave an extra 7BHP proved on the rolling road. To adjust fuel with your new ignition then you can use offthe shelf units such as the APEXi S-AFC to tweak your fuelling, this should give gains too.

To go more than the above your looking at engine work such as cams / ported head / bottom end balancing (i believe they are good standard though) and standalone stuff to run it all to take advantage of the new rev range. This costs silly money though, and if your after a serious amount of power on a budget, then a GT4 really is the way to go- not only do you get more power more easily as its turbo'd, more parts are readily avaliable and you get a 4WD transmission to put it all onto the tarmac.

If anyone spots any mistakes then feel free to correct me

HTH