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Minor Engine Modifications
http://www.gt4dc.co.uk/forum/viewtopic.php?f=13&t=3170		 Page 1 of 2
Author:  Exup [ Sat Aug 29, 2009 9:09 pm ]
Post subject:  Minor Engine Modifications
I have a Celica St185 Gt4 (JDM) it's had the cat taken out and a full scorpion exhaust system fitted. The air filter box has been removed for a home made k&N replica filter.

What should i be looking that could now damage the engine (to much boost)? or are these changes not enough to cause damage (just want to be carefull).

These things are new to me, any help on what to look for would be appreciated.

Ps What kind of BHP would i be looking at with these small changes?
Author:  Nibbles [ Sat Aug 29, 2009 10:09 pm ]
Post subject: 
We did a dyno session on a standard ST205 a couple of months back.
After doing a couple of runs with the car as stock, we removed the airbox lid and airfilter element - mimicking a good low restriction induction kit. This gained about 10BHP over a fairly substantial part of the power curve. We then replaced the airbox lid without the filter, and the resulting power curve was identical to the 'induction kit' one. The conclusion is that a good aftermarket panel filter element in the standard airbox will give the same power gain as an induction kit.

The downside of an induction kit is that you're sucking warm air from under the bonnet rather than cold air ducted from the front. On a ST185 with air-to-air type bonnet, the temperatures are horrendous - typically 60 to 70 C.

Also, if you're using a cheap K&N lookalike, you'll probably find it's as restrictive as the standard filter or it won't filter very well and let loads of fine dirt into the engine which will act like grinding paste on the bores.
Author:  Exup [ Sat Aug 29, 2009 10:43 pm ]
Post subject:  Minor Mods
As i dont have the standard air box, what would would you recomend as a better air filter replacement. Could i use the existing pipe work that ducts cold air from the inner wing wing to cool this filter.

When i bought this car i replaced it with a St185 engine from a mechanic (big end went on old engine). This engine hadn't had it's oil changed for sometime, the oil was like treacle. So before i put the engine into the rolling chassis it had a thourough degresing of the treacle (oil).

New oil and cambelt, plus camshaft seals replaced, engine in.

All i need to know now is what will removing the cat and a unrestricted exhaust, plus aftermarket filter do/or damage to the engine. I just want to play safe!



Chris-de-Bear wrote:
We did a dyno session on a standard ST205 a couple of months back.
After doing a couple of runs with the car as stock, we removed the airbox lid and airfilter element - mimicking a good low restriction induction kit. This gained about 10BHP over a fairly substantial part of the power curve. We then replaced the airbox lid without the filter, and the resulting power curve was identical to the 'induction kit' one. The conclusion is that a good aftermarket panel filter element in the standard airbox will give the same power gain as an induction kit.

The downside of an induction kit is that you're sucking warm air from under the bonnet rather than cold air ducted from the front. On a ST185 with air-to-air type bonnet, the temperatures are horrendous - typically 60 to 70 C.

Also, if you're using a cheap K&N lookalike, you'll probably find it's as restrictive as the standard filter or it won't filter very well and let loads of fine dirt into the engine which will act like grinding paste on the bores.
Author:  Strontium Dog [ Sun Aug 30, 2009 12:35 am ]
Post subject: 
The only possible problem (assuming the work has been done to an acceptable standard) is as Chris has mentioned the filter could well be crap. If it is more restrictive than a stock filter then it will rob power and increase fuel consumption to boot. Worse, if it filters poorly then you will likely suffer cylinder and piston erosion due to fine particulates getting into the inlet.

In short, get a decent filter! I use a Blitz SUS. It is not the best particulate filter but flows very well (sounds like Darth Vader on steroids under my bonnet). Possibly the best all round filter is the apexi but any good quality filter is OK.

If you are at all practical you should be able to fabricate a cold air box around your new filter and route a duct to it to supply cold fresh air. There are lots of pics around of engine bays with cold air boxes in to give you some idea. Job done! :wink:
Author:  Exup [ Sun Aug 30, 2009 9:42 am ]
Post subject:  Minor Engine Mods
Thanks for your help.

I was thinking of making a cold air box out of perspex, i will get hold of some perspex today. Im preaty good @ fabrication i used to be a welder fabricator, this should'nt be much of a problem. :wink:

Strontium Dog wrote:
The only possible problem (assuming the work has been done to an acceptable standard) is as Chris has mentioned the filter could well be crap. If it is more restrictive than a stock filter then it will rob power and increase fuel consumption to boot. Worse, if it filters poorly then you will likely suffer cylinder and piston erosion due to fine particulates getting into the inlet.

In short, get a decent filter! I use a Blitz SUS. It is not the best particulate filter but flows very well (sounds like Darth Vader on steroids under my bonnet). Possibly the best all round filter is the apexi but any good quality filter is OK.

If you are at all practical you should be able to fabricate a cold air box around your new filter and route a duct to it to supply cold fresh air. There are lots of pics around of engine bays with cold air boxes in to give you some idea. Job done! :wink:
Author:  Kris [ Sun Aug 30, 2009 10:18 am ]
Post subject: 
A cold air box is a good idea :)

Also changing to colder grade plug may add an additional safety margin :)

I recommend NGK BKR7E - you can get these off eBay for <£10 delivered for a set...
Author:  Exup [ Sun Aug 30, 2009 11:28 am ]
Post subject:  Air Box
Cheers :wink:

Kris wrote:
A cold air box is a good idea :)

Also changing to colder grade plug may add an additional safety margin :)

I recommend NGK BKR7E - you can get these off eBay for <£10 delivered for a set...
Author:  Sunny [ Sun Aug 30, 2009 5:00 pm ]
Post subject: 
Hi,

i does't know the exact boost limit of the ST185, but +0,2bar should work fine
means 0,7bar

greetz
Author:  Exup [ Sun Aug 30, 2009 7:33 pm ]
Post subject:  Boost
I dont know the standard boost of the St185, so i take it with the minor mods i have done, all should be fine.

Thanks for the info.

Sunny wrote:
Hi,

i does't know the exact boost limit of the ST185, but +0,2bar should work fine
means 0,7bar

greetz
Author:  Nibbles [ Sun Aug 30, 2009 8:08 pm ]
Post subject: 
standard boost on a 185 is about 0.5 bar from memory.

185's are prone to blowing head gaskets if boost is increased. Also, the top mount air to air intercooler (unless you have a CS or RC) is inadequate even for standard boost.

If you want a significant power increase AND reliability, prepare for front mount intercooler, metal headgasket and aftermarket ECU. Otherwise, enjoy the car as it is - they're not exactly slow even as standard.
Author:  Exup [ Sun Aug 30, 2009 8:43 pm ]
Post subject: 
I will stick with the minor mods @ the moment. As soon as more money is available i will upgrade head gasket, ecu and have a fmic fitted.

Cheers guys
Author:  Sunny [ Mon Aug 31, 2009 2:20 pm ]
Post subject: 
Hi,

you can also get a ST205 WTA-intercooler setup, cheap on ebay :)

greetz
Author:  Nibbles [ Mon Aug 31, 2009 4:17 pm ]
Post subject: 
Quote:
you can also get a ST205 WTA-intercooler setup, cheap on ebay


Not easy to fit to a 185 as turbo position is different and throttle body sizes are different. Also all the effort of persuading a pre-rad to fit. Only easy swap is a CS/RC complete intercooler / bonnet / bumper etc.

Generally easier / cheaper to fit a FMIC, and way better for most applications.
Author:  Sunny [ Mon Aug 31, 2009 4:47 pm ]
Post subject: 
Hi,

ST185CS-drivers told me that only the IC outlet have to modify?
ok, the others know more :)

Chris-de-Bear wrote:
and way better for most applications.


not more then a myth, but i agree with easier and cheaper :)

greetz
Author:  Diceman [ Tue Sep 01, 2009 10:12 am ]
Post subject: 
Hi Sunny,
Chris DB is correct. I tried back in 2003 to fit a St205 chargecooler to my old ST185 and nothing really fits.

ST205 throttle body rubber is larger than St185 & Cs (no you can't just bolt on a St205 one either as bolt spacing is diff). Chargecooler has turbo end pipe in wrong place, throttle body end is too large for St185 (50mm) or CS (55mm) throttle body rubber. You also can't just bolt on a ST205 throttle body complete or even a ST205 inlet manifold (I was trying to see how much would have to be changed to get the chargecooler fit and kept working back down the line. The only way to do it was to change to ST205 head, inlet manifold, TB, TB rubber, Chargecooler & exhaust manifold!! Might as well just swap the engine!

FMIC is easier, cheaper & better IMHO.

I still ended up removing the CS chargecooler from my latest Gt-Four and adding an FMIC anyway as IMHo it is jusst a beter tool for the job if done right.
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