Bob Rawle

Bit of an update, not alot more to add, car's been runing well at this level with no problems, I've added a cold air feed, in the fog covers is a vertical slot, it has a baffle behind it, I removed the baffle and then, having removed the airbox resonator, I have fitted a large pipe to collect the cold air and feed up to the two empty holes left in the inner wing, result is that cruise charge is now 1 degree above ambient as opposed to two/three. Given thats been in place for a cuople weeks and I have data I have now removed the under tray to see what effects that might have on charge air, oil and coolant temps, only just done so will report later in the week.

Thinking about it I'll take some pics of the air pipe etc.

bob

Bob Rawle

Pics below, car is a bit of a scruff, needs a good clean.

Tape is temporary, I wanted to see if it made any difference before doing anything fancy.





Undertray came of easily ..



Did a small mod here that might help ...

john banks

Do you think it is worth boxing in the airfilter so it can only draw air from your feed rather than other air that has passed through the radiator and near the exhaust manifold? Although cruise temps may be OK, what about under heavy load when more demand is placed on the intercooler and the suction at the airfilter is so much greater?

Bob Rawle

I might, but the temp rise under heavy load conditions is low, there really is no need except to help with "flood" when the cooling fans run, air intake temp (maf measured) sits 4-5 degrees above ambient, I expect that to come down now that I've removed the undertray, charge temp rise is "only" about 13-15 degrees after a hard 4th gear redline run, I was out checking the car after oil changes etc this lunchtime and had a bit of a blat with a Uk Sti PPP (stopped and compared brief notes at the BP garage but we were both heading for the French GP). From the roundabout at the motorway end we "cruised" up the straight all thro gears into 6th and it still only stuck at or about 18 degree rise, as speed gets above a level charge stabilises. With air feed cruise is one degree above ambient.

That said I have material in the garage to make something up so I'll probably do so to see what differences I might get. Now the undertray is off I expect it to behave very much like the STi5 in this respect.

I've still to "borrow" a manometer or two to check the pressure drop across the intercooler, damn I'll have to refit the undertray for that experiment.

cheers

bob

Nathan L

Would you be tempted to fit the recessed fog light surrounds to help further, as they are almost a funnel like shape and would direct air straight up the pipe?

Fog Lamp Trim Kit - Silver Part No. H4518FE050TG £32.50 (inc VAT)

Did the STi PPP owner want to know why he couldn't keep up

Nathan..

Wonder Wagon

I bet he wanted to know

PICKLE

Quote ''Did a small mod here that might help'' Am I being really thick, but what was that mod in the pic?? Forge DV is that it? Can you explain further Bob??

Bob Rawle

Cheers Nathan that's a good idea, watch this space, yes he did want to know, think he was somewhat suprised that I gave him about 8 car lengths and still caught him.
James its a throttle body mod, look at the top right area. On your car it would not be visible as you have a different throttle body but on a new age car thats where the water heating intake is (was).

cheers

bob

PICKLE

OIC! Gotcha..

marklemac

Bob, your pics are now missing ?

Bob Rawle

seems so, looks like an isp prob as the whole site is not accessible

bob

msgofast

Bob, great read and very good info, one of things i noticed playing with cold air was how much quicker you can make boost down low with cold air over hot air, boost threshold is reduced.

Michael

Bob Rawle

Cheers,

Nathan .... duly ordered arriving Friday fitted over the weekend ... cheers for that tip.

Means I can try an "issue 2" mod as well.

bob

Nathan L

No probs Bob, will look forward to finding out if it makes a good difference.

"Issue 2" Tell me more

Nathan..

Bob Rawle

I'll post a couple of pics if it (iss 2) works, if not nothing lost.

bob

marklemac

Bob,

Can you explain your throttle body mod please.

What exactly have you done, and what are you expecting from it ?

THANKS.

Bob Rawle

Disconnected the coolant feed and return to and from the throttle body, not rocket science and a common thing to do. So instead of heating up to 80-90 degrees centigrade it should remain at a lesser level.

bob

john banks

Bob can the feed and return be blocked off or do they need to be joined? Was going to do this tomorrow along with a load of other heat insulation...

Bob Rawle

I joined the feed directly to the return as that was the easiest way but you can blank them, it makes no real difference imho.

cheers

bob

Bob Rawle

Picked up the trims, took 2 mins to swap over, this will do the business, pics later

bob

Bob Rawle

Not tried it on the road yet, mapping till 10:20pm !!



Close up



cheers

bob

Wonder Wagon

that pipe fits like a glove

Bob Rawle

Yup, its a good match, deceptive in the pics, need to put a stainless mesh across it else I will lose rabbits up there !!!

Wonder Wagon

lol


or dog's

The Fixer

Bob, whilst having the version 7 inlet tract in bits this morning (turning the manifold ) I did notice that the tumbler housing to head matching is absolutely crap. There are steps of 3 to 5mm of head port sticking into the flow area of the tumbler housing. Now I know it wont give much in the terms of HP but Im sure that matching these to the heads would show some signs of improvement in extracting every last HP / ftlb on a budget like your trying to show. Something to try next maybe....

Bob Rawle

Yup you are absolutely right, the matching is terrible, however you mention "tumbler housing", the Sti's don't have those, they use "throttle body" type equivelants without the restrictions. I have no intention of lifting the inlet manifold yet.

general comment ...

My Sti5 is the car with all the fine detail tweaks added, the STi9 is about performance from basic mods, once I've finished with that then maybe, I say maybe as 370 bhp and 374 ft lbs is pretty good on the road, I will get to the detail on that car however I have no inclination to do that for as long as the '5 is sat circa 500 bhp. (at the moment)

I think what is important is what can be gained from simple inexpensive things, the fog trims cost £32 ... yet made all the difference to air pickup, the car is std apart from exhaust, induction, 3 port and remap, the air pipe is a bit of "interest" not any serious attempt to extract more performance as the turbo is the limiting factor right now. I published the info as I know there are folks out there with some interest in that. I keep getting mails about installing a barrier to isolate the induction from the engine ... all interest is appreciated but I said at the outset that I would post about mods as they were done, and I don't feel the need to do that yet for example, as the car is pretty damn good as is.

I'm sure that the matching between headers and heads could be improved as could the header interconnect joints as well as porting up pipe to turbo interface. Also spacing the inlet manifiold off with a heat barrier and disassociating the coolant header tank from the inlet manifold will all help temps.

cheers

bob

Bob Rawle

Some feedback ... throttle body mod, not sure thats a good move, started to get some stalling shortly after warm up so just reverted that mod and will see what happens tomorrow am, could be getting some icing up methinks.

Charge temps are now a solid 1 degree max above ambient on cruise and intake temps (maf position) are 2 degrees above ambient so cold air feed is working a treat. The extra degree in the intake is either offset or a bit of soak.

Added 0.6/0.7 degrees of ignition above engine load 4 ish across the rpm range, will see how that is tomorrow.

bob

Simon Lines

Intersting, on mine it's been fine so far

Cheers

Simon

Nathan L

I totally missed you had fitted the fog trims.

Looks good and you can just imagine the air surging up the pipe now

Bob Rawle

Simon its not related on mine either, I always go back to "last known good point" when ever I note behaviour thats a departure from normal. Since that was all that had been changed I reverted as a check. TB is now bypassed again. Readjusted throttle stop, and position sensor, should fix things. Revs drop a touch low when its semi cold.

bob