Harvey trick uppipe with small turbo
 

At the moment, I am driving WRX 04 with PPP and all cats in their place and my main concern is quite high turbo treshold (on 5th gear I see 1bar about 3200rpm, full boost 3400-3500rpm, on the 3rd gear 300-400rpm later), especially on quite long stock 5sp. gearbox.
I am preparing my car to a decat and suctom remap. The car is my daily driver and I want max reliability and the widest powerband possible. Currently I cannot decide if I stay on stock td04 or should I put td04-19t hybrid. So my power goals are somewhere between 270-320bhp (on flywheel).
I have read many good opinions about Harvey trick uppipe in terms of widening powerband and moving turbo treshold to considerably lower rpms. For sure it's worth putting it together with medium to bigger turbos, but what about the stock or hybrid td04? Will I see a difference between harvey's uppipe compared to a standard catless uppipe? Is there anyone who has any real life experience with it (preferably logs with turbo spool on stock versus Harvey's uppipe)?

Ive just fitted a Harvey up pipe to a TD05 and to be fair, dont really notice any earlier spool gains.

Im hitting 1 bar of boost around 3200 also then hitting 1.3 around 3400/3500.

Im testing increasing the wastegate duty to improve spool even more but thought id have to reduce it rather than increase it with a harvey up pipe

on your WRX you want to bin the cat in the uppipe then full or sports decat on the downpipe. Add a 3port, fuel pump and a decent panel filter and you'll have some very good gains in spool once it's all mapped in. Depending on what fuel you run the 270 goal can be hit on the TD04 - if you want more you'll be better opting for the STI turbo/injectors to get over the 300 mark.

I've never tried a harvey pipe on a TD04 - there's never been a case where a fit and healthy turbo has failed to deliver. Usually there is a bit of slack in the wastegate arm so when your fitting the up/down pipes check the adjustment on the arm, you want to have to pull it at a little to get it over the wastegate arm pin kinda the shape of a crescent moon. Just watch the little c-clip as they like to escape and fly all over the shop!

Normally if a car is getting a harvey pipe it will get the ported headers fitted at the same time and gains would be any where from 200-500rpm getting onto boost.

I have a Harvey uppipe with a TD04 (03 WRX), but hard to say what specific difference it has made as it was fitted along with a sports cat down and decat mid, then remapped. As you can imagine the difference as a whole is night and day.

Max boost comes in about the same at 3500rpm, but car is noticeably more responsive lower down. New turbo whistle on throttle is a giveaway of faster spool. I'm not an expert by any stretch, but the Harvey or STI uppipe were the two uppipes recommended to me by Richard at FB Tuning, who carried out all my work.

I have a Harvey uppipe going on soon (when I get the courage to start removing all the old corroded nuts) it's a classic (MY00) running 283 and 300 lb/ft on the TD04. I will let you know what difference it makes when fitted and mapped.

You need to eliminate the precept up pipe, wether you fit an STi replacement or a Harvey pipe the changes you see will be very similar, the Harvey up pipe was not designed to improve the spool of the baby TD04 ... lol, and harvey would not have recommended it aside from a cat replacement pipe

The engine is not efficient below 3400 rpm in any case so making boost very early is not going to gain you much, be careful you don't push it into surge doing that

I understood the Harvey up pipe had an effect also on small turbos such as the TD04 and it was because of the changes in the pipe's internal diameter. If it doesn't do that then I've been mislead and if anyone wants a brand new up pipe get in touch!

when i measured the end part of the tubing on my standard up pipe it measured something like 43mm. when i measured the Harvey pipe its about 44 or 45mm, now not sure if the deeper down tubing is narrower (cant measure that lol ) but so far ive had no benefit from fitting the harvey pipe to a TD05, my spool is the same as standard up pipe from the logs im taking.

im measuring with a crude tape measure so these measurements are not specific to the exact etc

Good to know this before I start removing the corroded old nuts to fit it which might turn into a ball ache of a job.

Oh yes, depending on the age of the car it can be an "easy" job or a bloody ball ache.

In my case, 2 yrs of original nuts n bolts it was the latter, had to remove the turbo with the up pipe still attached ! as the nuts were solid and rounding off, no matter what method of removal, heat, several sockets etc, in the end, turbo was removed with up pipe attahced and chiselled the nuts off, took hours !!!

so be prepared for the latter and if it goes well then enjoy the easy ride lol

best spool improvement i,ve seen on my own car with 18g was to port the headers(standard subaru headers)...no power advantage up top but definately pulled onto boost much earlier circa 3-400 rpm-one of those eureka moments when i thought -why did,nt i do this years ago lol

not a harvey pipe but half the price lol but on the tdo4 its made a HUGE difference spools so much better
happy days

Im now managing after some tweaking of the Map to hit 1 bar at 3000 - 3100 depending.

So a combination of map tweak and the harvey pipe , who knows lol

what exactly do you mean?

+1 above.

What do you mean lol.. what do you want to kno I've clearly stated what I said :)

You said " not a Harvey pipe but half the price" ....

What was half the price?

Yup I have a up pipe but it's not the Harvey pipe and it was half of the cost lol

blood out of a stone

so what up-pipe is it? :Suspiciou

Right.... well done :thumb:

So what up pipe is it then ???




Christ this is hard work :brickwall

Prob just a sti up pipe lol .

would that be cheaper and better than a harvey pipe?