BLUE TII

iTrader: (9)

Well, you may be sacrificing power on the dyno print out, but the more responsive turbo could actually put down more power when driving.

This is because the dyno does not show elapsed time of the rpm sweep.

If the smaller AR housing turbo takes some milliseconds to hit full boost and the larger AR housing turbo takes over a second to hit full boost the smaller AR turbo will have been accelerating the vehicle at a higher rate and by the time the larger AR turbo is up to full boost the smaller AR one has been at full boost for a while and has dashed through several hundred more rpm where it is making more power than the larger AR turbo at full boost at its correspondingly lower rpm.

It is a balance and you have to size all aspects of the turbo for what you are doing with it.

1.45AR may be fastest at a drag race where you leave the line with boost from a 2-step and flat shift each gear.

The 1.05AR may be fastest in a roll on race or exiting corners on a tight road course.

Brilliant7-LFC

iTrader: (7)

That's another excellent point! I hadn't considered the time factor for the rpms and power which makes a ton of sense. All the same, I think I will focus on optimizing the setup and reducing my lag through other means.

While I have the focus of so many brilliant minds (I'm being genuine here...you guys are huge wealths of knowledge) what do you think about a 2.5" inlet/outlet on the intercooler with 2.75" piping? I'd have to use reducers on the inlet and outlet as my output from my compressor housing is 2.75" and I believe the GReddy elbow is also 2.75"?

Should I go through the trouble of modifying my intercooler to accommodate the 2.75" piping, or just deal with the reducers and sacrifice a little bit of flow?

There will also be a slight uptick in velocity through the intercooler which I view as a bad thing as it would have less time to be cooled since it's speeding up on its way in and out. Maybe I'm reaching here...

Nick

Howard Coleman

iTrader: (6)

here's a pic of my engine compartment w the mica barrier



ceramic coating's biggest plus is it mitigates rust. don't look for significant heat reduction.

the current turbo on my car is a BW S300 SXE 62 w a .91 housing. i am going to run it max and then switch in a 1.0 to compare.

BLUE TII

iTrader: (9)

Sounds good to me.

What I did is slowly step it up from the turbo to the throttle body.

My idea was that even though the intake is losing velocity from the friction of going though the intake piping it would also be continually expanding so it doesn't build up as much a head that the turbo has to push. Like the idea of megaphone exhaust piping I guess.

I did 2" turbo outlet to 2.25" IC pipe to 2.5" IC inlet to 2.75" IC outlet to 3" max inside the TB elbow.

Brilliant7-LFC

iTrader: (7)

Yeah, I saw this picture in your manifold writeup. The mica seems to be a good fit, I'm just not sure I have the clearance, but we will soon find out. I'm going to bite the bullet and buy a sheet.

That's an ideal way to do it I suppose. The only issue with my setup is that it reduces at the intercooler, which in theory would cause some sort of back pressure to the compressor housing.

My compressor housing has a 2.5" outlet but I've got one of those aluminum caps to make it 2.75". The piping is 2.75" down to the intercooler, where I'd have to use a reducer to 2.5" into the intercooler. It will then be 2.5" out of the intercooler with another reducer, bring it to 2.75" up to the throttle body essentially. It's a minor thing, but perhaps it'd be worth the trouble to have 2.75" pipe welded to the intercooler instead. My father in law can weld after all, but it will be a fair amount of work...

Nick

Houstonderk

iTrader: (3)

Let me know how you enjoy the 4088, I am running one as well with the 1.08 turbine housing and 4th gear is terrible with lag. Although once it gets going, it goes. Almost thought about going down to .95 as I want more road course type quickness, but recently did a track and stayed in 3rd most of the time. I had the ptp blanket and had to really really squeeze it between the intake and housing but it went with some tugs. Didn't need to do anything to the shock tower, this is the rx7store kit.

Brilliant7-LFC

iTrader: (7)

Hey buddy. I plan to take some videos after the tune so keep an eye in my build thread.

Do do you have any pictures of your setup? I'm curious about how much space you have compared to me.

Nick

KNONFS

iTrader: (14)

Cant wait to see the results, as that will probably be my next turbo, with the same .91 housing!

IRPerformance

iTrader: (41)

I've used these many times when there were clearance issues preventing the use of a heat blanket.

https://www.designengineering.com//c.../form-a-shield

Heat Screen 010401 | Purchase DEI, CryO2, Ny-Trex, Boom Mat & SPA Turbo Products | Design Engineering, Inc. - Thermal Performance Products

https://www.designengineering.com//c...hesive-backing

https://www.designengineering.com//c...at-shroud-gold

Houstonderk

iTrader: (3)

Not anything real good as I have the engine pulled now, but as mentioned I basically took a long flathead and pushed where the metal clips are on the end to slip between the housing and manifold.

Brilliant7-LFC

iTrader: (7)

Yeah, I have an A-Spec manifold so they seem to be a bit different. My clearance on the LIM isn't great but the shock tower clearance was non existent so I had to "massage" my strut tower support.

I just swapped out my USDM LIM for a JDM version which grants a bit more clearance due to its smaller EGR castings, and had it ceramic coated as well.

Howard, you will be pleased to know the Mica barrier is due to arrive today, so we'll see how it all comes together in the next couple days.

Nick

Gilgamesh

All this talk of lag makes me wonder if you were street driving your FD, how far would a set of RX8 4.44s go towards having a nice street set up.

Houstonderk

iTrader: (3)

Well I technically just found low compression on the engine(60-70s) and a somewhat bad super thin gasket between manifold and turbo. So the engine is getting redone as well as a good quality twin scroll gasket for the turbo.

Brilliant7-LFC

iTrader: (7)

To quote Howard earlier in this thread, I think that may be the tail wagging the dog. Having shorter gearing will get me through the RPM's quicker, but it's not solving my "issue" any. It's just making me shift more frequently and in my view, moving me through the best part of the powerband faster. My turbo should breath quite good at higher RPM's, which means it will make better power up top, comparitively to the lower end. So, to have shorter gears get's me out of the "sweet spot" faster.

I stand to be corrected, but that's how I view it.

Sorry to hear about that bud. The lower compression would have an affect on the spool time, perhaps that's partially your cause for the lag you described earlier...?

Nick