Doh! Obvious now you say it

 

Tim,
Harvey is suggesting they can potentially benefit from light porting to match gaskets etc.

 

Yep. There are big benefits from porting the cast headers as fitted from MY93 up to New Age ? The ported headers should be run with a matched purpose designed uppipe. The tubular headers, except for the very first examples, are made to such a fine standard but all you are doing is minor tidying up work and any improvements from working on the headers and uppipe only will be small and therefore probably not worth the effort.

 

In other words they are very good headers (OEM tubular ones), so don't bloody change 'em! (Only pulling your leg Tim)

 

It will be very interesting to compare before and after...getting a new RR plot tomorrow to act as the reference for when I swap back to the OEM ones (once I've found some!).

 

I heard these will soon be available with billet magic inside )))
anytime soon?

 

Anymore info as I am thinking about buying one, but don't want to get an 'old' version.

 

Any news yet Tim

Tony

 

Bit of a saga really.

Went to the RR as advertised, but the results were dismal. It appears the car had pulled a load of timing for some reason, perhaps a bad tank of fuel, and it meant I didn't get the reference plots I wanted

I have now got a set of OEM headers to fit, but I also found that my APS twin port DV was leaking! That, according to Simon, would mean the whole map is probably off and could account for the odd results etc.

It's now cleaned and adjusted "tightly" to raise the pressure at which it starts dumping and, as well as dramatically improving the previously lumpy idle, the boost threshold is radically improved: 1 bar at 2900rpm and 1.6bar at 3300-3400 rpm

It's running without a DV at the moment just to compare, and to make sure the APS is not still leaking (it's not) but I don't like the noise, and think it actually goes better with a DV fitted so it will be put back on soon.

I will be up at Surrey Rolling Road next week for Simon to tweak the map on the existing headers, and I'm booked in a week later (should I still need it) for the headers to be swapped back to OEM and another map tweak.

So, fingers crossed, all should be finally sorted in either 1 or 2 week's time

The car is actually tremendous to drive now, so I'm hopeful I may not actually have to fit the OEM headers...although that said I suspect the power may be limited by the narrow-bore Tomei/Lateral ones, but we'll see.

 

Now I've got a set of OEM headers I've taken a look and see what you mean.

If I line up an exhaust gasket with the pipework there is absolutely no need to open them out at all

The welds between the flanges and pipes could probably do with a clean as they bulge a little and have a step - although the step is "back in" to the pipe after the flange rather than a ledge sticking in to the flow, so would not, itself, impede flow.

I might just take the dremel to them to clean them up a bit, but I doubt it will make much of an difference tbh.

I'll take a photo tonight and post it up.

 

Hi,

I own a 2005 SPEC C type RA car. I'd want to upgrade my stock vf36 turbo and injectors. Actually my car, with custom map, sti sport filter, and full miltek 76mm exhaust, have about 345ps and 47kgm of torque.

I'd want a power in region of 420/440ps and more torque. So i ask if, in your opionion, with LM420 or LM450 (58mm intake version and with 800cc injectors of course) i can reach that power without change the IC or other parts.

The point is that i dont want to buy a superturbo (like LM420/450) is then i cant reach all his power with my configuration.

Every comments will be very apprenciated .

Thks

Carlo
Italy

 

lm450 should make 420 on tmic imho

Simon

 

Not the best photo, but should give you the idea:

 

Yes Tim it is more a clean up than a port but "manny a mickle maks a muckle" so it all helps.

The first few cars with these headers did need work on them but obviously the manufacturing process was refined after they had made a few.

 

Fair point

In the same vein, and in your opinion, is it worth junking the standard heat shields and wrapping them?

 

Wrapping the exhaust housing is far preferable. Heat retention from wrapping the turbo properly is far better, the insulation properties are very noticably better and the under bonnet temperatures tumble.
On a wrapped turbo you can put your hand on the outer wrap cover. Try doing that on a factory heatshield which has a big surface area to radiate heat into the engine bay.

 

OK - thanks Harvey. The turbo's already ceramic coated, but I guess heatwrapping wouild not go amiss as well.

And I'll save myself the hassle and leave the OEM heatshields in place

 

Carlo,

To give you a rough Idea in the UK on 99ron with those mods, you would expect about 365ps & 50kgm on UK rollers

from what i gather, with your own Mods and just a Turbo and injector upgrade

The LM420 probably produce on your italy rollors around 410ps and 55kgm
The LM450 probably produce on your italy rollors around 440ps and 58kgm

IMHO IIRC

Tony

 

Tim,
Be VERY careful when porting the entries. Take too much out and the flange will break off.... since you have had problems with other "flanges", I would steer clear!!!

 

Noted, Shaun - I am only cleaning them up a little as I can see what you mean

 

Thks for reply. I tried my car in several Dyno (Maha and other) and the power was always similar .

 

Tim : No.
If the turbo is ceramic coated just leave it at that. Some years ago before ceramic coating was popular I coated and wrapped a set of quality tubular headers which subsequently failled prematurely and the coating was also flaking off.
May not be the same on a cast exhaust housing but I would not risk it as there has to be a degree of heat loss.

 

OK - thanks Harvey

 

No problem and of course including a remap

 

About torque; do you think that max torque will be in 4500 rpm region for LM450 and 4000/4200rpm for LM420?

Thks

 

Went to SRR today for Simon to check map etc.

I still had suspicions about the DV, because the performance seemed to vary day by day and all I could think might be to blame was the DV - so I removed it prior to Simon starting.

Simon confirmed that it was running a little lean, so without a doubt the DV had been leaking when the car was last mapped. Don't think I'll bother to refit it as less things to leak, and I'm getting used to the sound of strangled squirrels when you change gear

Then did two runs - one was 460bhp the next was only 420bhp. This appeared to be a repeat of the previous experience at Len's, and also what I've been seeing day by day.

The issue was eventually tracked down to the AVCS and by removing half of the advance, repeatable figures were obtained. As an aside, a report by Tomei I came across revealed that the 2.5 STi has 20 degress of AVCS advance, compared to 40 degrees for the 2.0l - there must be a good reason!

And, the results are:







I now have a reliable 460bhp/440lbft build, mapped at 1.6bar. Boost curve is very flat and, on the road, 1 bar at 3000rpm, 1.6 at 3500rpm (on the RR 1 bar at 3500rpm, 1.6bar at 4100). All with a centre cat by the way.

Peak power is 5700rpm and >420lbft from 4200-5700rpm, >350lbft 3700-6600rpm. Nice

Simon's view is that 1.6 bar and 460bhp is perfect for the EJ257 block - some people run more, but it should be nice and reliable.

Torque is lower than I'd hoped, but the "area under the curve" is not half bad

The stock ECU is probably preventing fine tweaking of the map, as there's not enough resolution in the tables...but £1200++ is a lot to pay for maybe 20bhp and 30lbft or so.

I now need to decide whether to bother fitting the OEM headers. They may increase top end power, but it might be at the expense of spool....do I spend the time and money to try it, in the interests of science, or should I just get on with enjoying the car. Really not sure...I'll sleep on it...tune in, same time, same channel, for the next exciting episode...

 

Tim,
Just enjoy the car mate, but if you have a set of OE headers you can try.... I would.

Who's telling you this Tim?

 

Yep - think you're right...might just have to, since I do have a set
Various folk, both genuine experts as well as the "armchair" variety

Have PM'd you Shaun

 

not strictly so.. the AVCS setting were custom as they are for every car I map but normally tend to find reducing the advance as the rpm increases gives the best results but not the case with Tim's car.. run the car with AVCS on compared to off and with sensible advance and it spooled better but lost around 40~50hp at higher rpm even though the advance has returned to 0 at that point.. it just worked a little different..

no issue with not enough resolution as it is not maxxing tables and there is enough maf curve.. just you would gain the usual small amount with faster processer and higher definition ignition and fuel maps etc.. it is just difficult to put it into words and quantify it.

If you are now happy with the car Tim it maybe worth using the megarom (seeing as it now works on your car) and fine tune the in gear boox control and launch control etc.

Simon

 

oh and not having a dv leak made it much nicer to work with and enabled flat boost profile