I would look at having a compression test carried out and check for leaks etc by a reliable specialist. You may also need to look at going onto a 3" downpipe to help flow. I had the same problem with my old bug sti and was restricted to 341bhp using a vf48 and meth. Once i had the 3" fitted and map tweaked the car made over 370bhp.

 

What make is your silicone inlet pipe? Looks to me like it might be getting sucked shut.

 

Boost drops like a stone when that happens

 

on my02 sti im running

fuel pump
front mount
induction kit
3 inch decat system
vf48
tubular headers

mine only made 355bhp so now i looking for a 20g turbo

 

Im considering the compression test as its not overly expensive to do. Would I not notice lazy cylinders though?

using a 3" to 2.5" downpipe but looking for full 3" system now, also bought gtspec2 headers.

Samco

That it does not as you can see.

 

I wish I had skipped the 20g and gone straight for a 321t or sc46 bud
one of the mappers may tell you different though as I could be talking out of my ****

 

That is decent power from a vf48 without using meth, the headers you are using might be a bit over kill at that power level and costing you earlier spool. Ported headers are more suited for cars running anything upto 400ish bhp. You may also want to look at a Harvey/ AFP 20G or a SC38 as these would give better performance over the normal 20G.

 

ok wicked cheers ill look into it mate

 

My dads has a bug Sti with vf35,3" exhaust and tubulars mapped by Jgm and it made 340+ bhp and 320 llbs +

 

Been playing with the data monitor in the car and its telling me the CT Coolant temperature is around 90-95C after a good run on idle and 80-95C when being driven hard. guage stays the same on dash and looks normal. Are these temps normal/ok??? and could it be an indicator of my problems?

 

those temps are spot on mate. Another possible cause could be NPS sensor but only way to confirm this is to have a laptop plugged in and checked over.

 

Something is not right there,with your spec you must making at least 360bhp+...

As above visit someone who can carry for you compression test.

Plus NPS as above suggest LJF can be too


Jura

 

Duff NPS common on bugs. Mine being replaced this afternoon.

 

checked after the dyno run and no problem with nps

Looks like a compression test is on the cards....... fingers crossed.

 

This is the same issue i was seeing with my car! Low on power for what it was, i was low on compression on one Cylinder.

get it gone, it wont cost much, make sure you use a good gauge tho.

Andy

 

I have been talking to Andy Carr about taking another look (I've been a bit harsh on him through frustration). He is more than happy to take a look. Its to be done at the garage that carried out the work and I will be asking them to check compression as its seems to be the top answer.

Cheers all, I will keep you updated of the findings and for those of you that have offered their services, I will contact you if I have no joy

Andy

 

Andrew is a very very good mapper!!! and hes honest!

 

yeah i have heard he is the don of motecs

 

Compression is down on all four 115 on the left and 125 on the right after 15 turns.

 

thats a bummer dude no time to get upset, time to upgrade!

 

So sorry to hear that mate


Are you gonna leave it as it is or build it stronger?

 

Cheers, going to run it as it is for now as its my daily drive, but will be saving for a stronger build along the way. I could have done without it though.

 

i had similar problem this time last year, low compression on a 2004 sti, turned out it was the valve seats had worn, perfect excuse and motivation for you to upgrade though.

 

Bloody Cars!

At least you know why its low on power mate... this is how i found out about my issues and then had it tested i was low on one clyner

 

Andy Carr and Pole position both believe its probably nothing too serious as its so evenly low across all 4 and suggests its possibly had a bad rebuild somewhere down the line in its past. Either way by the time its apart I may as well change a few things anyway even if they are found to be fine

 

Sorry bit of a resurrection here.
Incidentally what's it supposed to be?

 

+2

I've had Andy Forrest,Simon aka JGM and Andrew Carr the latter twice 3rd hopefully soon.
Also a 20G too can't complain power was excellent.

There must be some gremlin doing something somewhere

 

I can't remember if its 160?

Funny you should bring this back up. I am paying for a newly machined CDB on Tuesday ready for a 2.1 build. Cars been running fine for all this time so whatever it is, it isn't getting worse so could point to Poles theory (incorrect gaskets used/wrong thickness) being correct. before I do hand over cash though I have arranged for Andy Carr to take a look at the map again (bit hopeful really).

 

3" Done today .

 

Let us know how you get on with the map tweak mate.