Subaru Impreza GC8 & RS Forum & Community banner

2261 - 2280 of 2552 Posts

·
Premium Member
98 2.5RS - V2 WRX Swap
Joined
·
1,593 Posts
I hate tire shops.

Remember with ignition, if more advance is better, LOTS more is LOTS better....That's how it works right? :lol:

Have you ever punched your data into virtual dyno? I've found it pretty useful to compare changes.
 

·
They call me Garrett
98 RBP V4 STi Swapped RS
Joined
·
4,082 Posts
Discussion Starter #2,262
Yeah I've done it a bit to see small dips in torque. Seems to be a useful tool. I'm mostly just fixing up some drive-ability stuff right now and will give her more beans when I get my downpipe on ONE of these days..
 

·
They call me Garrett
98 RBP V4 STi Swapped RS
Joined
·
4,082 Posts
Discussion Starter #2,263
Zero/Sports Downpipe

Hey! It's been a while since I've posted in this, and I finally got something worth posting about. I'm gonna tie this post in with the modification as well as some tuning stuff in a post below, so read both!

Alright this one is a simple one.

I bought a Roger Clark Motorsports downpipe for a twinscroll turbo. It was too short. I didn't feel like dealing with welding because I'm lazy and sort of wanted an excuse to get a different exhaust anyways. I searched for a while looking at some JDM length exhaust options, and honestly the used marked for JDM length exhausts is a large amount of bullshit. Certain importers, I won't say names but it starts with a J and end's with a DM Racing Motors, have used dented up exhausts for more than they are to buy brand new on a site like Japanparts... trash. And it's not just them, but every other importer everywhere.

So I looked at some new exhausts.. meh... didn't really want to spend the money to have unknown fitment, sound quality, and the inability for the exhaust to be sold back if it didn't fit.

So I started to look at GDB F-G type downpipes, which are the same length as the USDM ones.


I came across this Zerosports downpipe in great shape. Decent price. Let's do it.






Got it in, and it's definitely gonna fit.

I liked the fact it had a small resonator on it at the end, but sort of didn't like the fact it had a cat.



Here's the important bits compared to the OEM downpipe.





I'm not really sure of the benefit of the extra half circle section, or if there is any.. but the OEM downpipe definitely has a more open bellmouth that's smoother because of the casting and not welded together pieces.

Where the Z/S one IS nicer is that in right after that initial area, it opens up to a wider 3in pipe as well as has a smoother transition in piping. Hard to tell in the pics, but that's the situation.

I was going to post the pictures I took, but they are pretty useless. The Z/S downpipe has a webbed cat, but it's MUCH less dense than the OEM one, as well as skinnier. I'm ASSUMING this promotes better flow, but I'm a software engineer and it doesn't have beeps and boops so I can't say for sure.


I wasn't super thrilled it had a cat, but oh whale. I can always stamp it out later like some sort of lunatic. Glamor shot of the badge before it gets covered up by the heatshield





Got everything on, and turned the car on.


Volume is just a SMIDGE louder, and clarity of sounds is much better. I really, really like it.

I didn't toss a tune on the car yet because it seems like the OEM feedback system can handle the boost fine, but I haven't done any purposeful high boost, low speed testing yet.

It definitely likes to spool the turbo up a lot easier now. I dig it. Time to up boost a little!


Here is my log from a small 1-2-3 pull:

https=://datazap.me/u/equinox92/new-downpipe?log=0&data=3-10-12-14&zoom=2801-3056

You can manipulate data and look at it with the full log here, or for the lazy/phone users:




Not a super telling pull, but enough to see that it's not gonna be huge issue without a tune.
 

·
They call me Garrett
98 RBP V4 STi Swapped RS
Joined
·
4,082 Posts
Discussion Starter #2,264 (Edited)
+ more tuning stuffs.

Here's a solid 3rd gear pull with the stock DP on still, and 93 octane.



datazap.me | equinox92 | Third gear pull





Small amount of learned knock, but not this event. Totally safe!

I think timing could be smooth and improved a tad, which I am doing slowly, but there is no torque loss/bumps.

Also, here is Virtual Dyno's rendition in orange:




I don't think the absolute number is true, I was also driving up a hill on the onramp to a highway when I did the pull, and i don't have a true vehicle weight nor a proper front surface area.

The big point is comparing it to blue. There is a nice bump from the blue line, which was a previous pull and tune. It's a 2nd gear pull, so the data isn't as accurate, and I don't think I hit full throttle until about 4500 RPM so the torque delta isn't accurate either.. but the power from 5000 onwards is real and I'm sure I improved on it.

If anyone wants to download the tune, or even just look at it, check it out here: ECU Revision 7.2 7-10-2018


The only other thing I need to note is that I do have my Fuel Trim column lowered a bit so OL is scaled by quite a bit (additional fuel during both logs) and I need to change that. I don't like how much extra fuel it's dumping in the engine and I've got a pretty damn high injector duty cycle for how little beans it's running.
 

·
They call me Garrett
98 RBP V4 STi Swapped RS
Joined
·
4,082 Posts
Discussion Starter #2,265
23mm Zero/Sports Hollow Rear Sway Bar

After driving on the track and seeing some of the pictures of how the car loads up in corners, and feeling how it reacts I decided it was finally time for some sway bars. I found a good deal on some of the swaybars I wanted and I bought both the front and rear. I only had the hardware right now to do the rear, so I guess I'll separate these into two posts.

The reason I chose these Zero/Sports bars are because they are hollow, 23mm and balanced front to rear (when the front goes on). The hollowness of them gives them a bit less stiffness than a solid bar, however the weight savings is a huge amount. I didn't have my scale out, however based on the hand test I'd say the hollow bars knock about 4-5lbs off of unpsrung/sorta-srpung mass. The hollow 23mm should also give it just the SLIGHTEST more stiffness over the factory STi 20mm bars, which is exactly what I am looking for instead of upping the spring rate.

Anyways, on to install pics.

In order to use the provided 23mm bushings, I needed to switch to the newer/different style of bushing clamp.. this also meant I needed to switch brackets. No biggie, ordered new parts and away we went..










The interesting thing to note is that the clamps operate a bit differently. One has a slot and a bolt hole, the other has a stud and a bolt hole. I really like the stud and hole one better as it makes installing much easier... likely the reason why they switched to it in the newer years.

Comparison of the old vs new bar..




And a few more bolts later...



Boom.


I'm a bit hesitent to want to push the car while it's got a bit of an unbalanced rear swaybar and while the car isn't corner balanced... but it shouldn't be that big of a deal on street driving. I do think my front end has tooooooo much weight on it, even for a Subaru... but I'll correct that soon.

I'm just waiting on some bushings for the front and I can get those installed... hopefully there are no other surprises.

I haven't driven the car yet, but I will update if there is a notable difference in stability or dynamic car feel... I'm not expecting a ton.


That's it! I'll update the journal when I can get the front one in.
 

·
They call me Garrett
98 RBP V4 STi Swapped RS
Joined
·
4,082 Posts
Discussion Starter #2,267
Tossed the car on our corner balance scales at work. Didn't have any tools with me to adjust, but that's next.

I had a full tank of gas, and probably 30-40 lbs of crap in the car thrown about. Whatever that's worth.

Without me:





With me:




So there's a bit of work yet to be done... really wish I had ride height and preload adjustments separate..

I'm happy with the absolute weight of the car though!
 

·
They call me Garrett
98 RBP V4 STi Swapped RS
Joined
·
4,082 Posts
Discussion Starter #2,270
Raised the car a tad tonight.

Also started to mess with my front swaybar.. waiting on some other parts and I can make it work.. it's a bit more complicated than at first glance...

The good news is that Zerosports actually shipped me parts direct from their store!
 

·
They call me Garrett
98 RBP V4 STi Swapped RS
Joined
·
4,082 Posts
Discussion Starter #2,272
Koyo VH090302 Hyper V Aluminum Radiator

After dealing with issues with the plastic end tank radiators, I decided I didn't want to deal with that crap ever again. It was a bit of a hassle getting to this radiator as a lot of other older radiator part numbers were discontinued, but Koyo basically upgraded their cores and made them stock size thickness for easy install!

This radiator was technically made for the 91-94 Legacy turbo, however because I was still using a lot of my 98 STi stuff, everything was the same! This is a great option for turbo GCs... the only caveat is that you need the proper Phase 1 metal shroud fans which are a pain to get if you don't already have them.

The only other issue I ran into, was that because I have the Phase 2 AC lines and condenser, it didn't fit with the radiator. I've been kicking myself in the face for not keeping my Phase 1 stuff around and I guess I'll just end up buying the entire 98 Impreza AC stuff.

Anyways, pictures:










So far I haven't driven around enough to noticed a differential in temperature.. but it did take about half a gallon more coolant than the stock one. I don't expect there to be a huge change.

I am going to use one of the pressure test plugs and put in a coolant temp sender to run back to my DIN pack... because why not?


More on that later.


Everything bolted right up and fit in like OEM. Gotta love Koyo for that!
 

·
They call me Garrett
98 RBP V4 STi Swapped RS
Joined
·
4,082 Posts
Discussion Starter #2,273
STi Stainless Clutch Line


My clutch fluid looked like garbo... I had this stainless line laying around... I swapped the fluid out and put it on.


:shrug:










Clutch MAYBE has more feedback?

I dunno.
 

·
Registered
Cheap Kitchens
Joined
·
1,874 Posts
Good info about the radiator, what top hose are you using? I have tried many different years and models but have yet to find the right one
 

·
Premium Member
96 Impreza Coupe
Joined
·
1,577 Posts
Just for anybody else looking for The A/C parts it’s not phase I vs phase II. The condenser is 98rs only. The other models(93-2001 impreza L, 99-01RS) use the same type of condenser that won’t fit with the side tank radiators.

The metal fan shrouds are the way to go as they are slimmer than the plastic ones.

Garrett, did you fine the A/C condenser off a part out?
 

·
They call me Garrett
98 RBP V4 STi Swapped RS
Joined
·
4,082 Posts
Discussion Starter #2,276
Good info about the radiator, what top hose are you using? I have tried many different years and models but have yet to find the right one
I've got the GC Samco hoses, but my RS stuff fit just the same.

Just for anybody else looking for The A/C parts it’s not phase I vs phase II. The condenser is 98rs only. The other models(93-2001 impreza L, 99-01RS) use the same type of condenser that won’t fit with the side tank radiators.

The metal fan shrouds are the way to go as they are slimmer than the plastic ones.

Garrett, did you fine the A/C condenser off a part out?
Yep, it's 98 stuff only. Easier to differentiate with phases based on the confusion. 98 was such a weird year...

I haven't gotten an AC parts yet. I've got the full system from an 00 RS in there, minus the condenser right now. Getting the 98 parts is a pain... and my car was a 98 so it had all the RIGHT parts.. but when I put my 251 in and reshelled the car... 7 years ago or whatever I swapped it over to the Phase 2, newer stuff... it's been a long journey haha.
 

·
Premium Member
96 Impreza Coupe
Joined
·
1,577 Posts
Yeah, it is a pain to find. I have been searching(I haven't really put up and WTB). I'm gonna see if its possible to cut and clock the non 98 RS condenser line mounting blocks then weld it back up.
 

·
Registered
2001 SRP RS Coupe, 05 FXT
Joined
·
294 Posts
That's some nasty looking fluid!

All good info on the radiator, thanks guys. Are you limited to only using the metal shrouded fans? Are those only found on a 98 RS as well? Or, could you fit some slim SPALs with custom brackets on the Koyo?
 

·
Premium Member
96 Impreza Coupe
Joined
·
1,577 Posts
That's some nasty looking fluid!

All good info on the radiator, thanks guys. Are you limited to only using the metal shrouded fans? Are those only found on a 98 RS as well? Or, could you fit some slim SPALs with custom brackets on the Koyo?
They are also found on the 98 RS, I believe the 98 forester has the same fans and shrouds. With a custom bracket you could mount SPALs to any rad. I just like the OEM fans best. They have much less issues than almost any aftermarket fans.
 
2261 - 2280 of 2552 Posts
Top