Benjamz

Bryan, I got the turbo back. Too bad the guy wants to sell the kit now. Thank for everything.

gregs

iTrader: (7)

Update: Today NGO and myself did a quick test on my car...we removed the boost gauge from the vfad source on the upper intake manifold and placed the boost gauge source to the outlet pipe on the turbo (greddy fix #2) took the car for a few boost runs (still have a boost read out on my greddy profec boost controller which has the source from the vfad)

Once driving the car into boost the turbo (source) boost reading shows 15 psi and creeps to 16 psi in upper rpm..on the greddy profec which only shows peak boost 13.6psi ...let me know what you guys think (remember i am still on the stock greddy intercooler)

Brettus

iTrader: (2)

when you say "peak boost" is that the actual boost at upper rpm or just the peak somewhere lower in the rev range .

And yeah - sounds similar to my experiences .....

gregs

iTrader: (7)

peak boost meaning lower rpm

gregs

iTrader: (7)

whats interesting is at boost at the turbo from 6k up to redline creeps up instead of drops

Brettus

iTrader: (2)

Exactly what I have seen also . MM said my system was screwed up . Now that i see someone else with the same thing i am thinking it is the 50mm tube to the IC that is the issue ....


MM uses 58mm tube there so think i'll upgrade to that .

Larger IC did not make that much difference for me .

Brettus

iTrader: (2)

which could also be the reason why a larger actuator might not work that well .

At low rpm if you set the Boost controller duty cycle for say 10psi - the pressure in the actuator is 10psi also . Higher in the rev range your DC is the same but you now have 16 psi in the actuator and it pushes the WG open .
You may be able to resolve that by taking the line to the solenoid from just before the throttle plate instead of just after the turbo .

Bryan@BNR

There is a restriction of flow in the intercooler. It is wise to get a Garrett or a Spearco core. Ebay specials are not proven to be the best intercoolers. They are definately eye candy, but you get what you pay for...

I am happy we are making progress. 16 psi all the way to redline on the turbo side boost gauge and boost drops to 6 psi on the engine side boost gauge. That is huge pressure and volume loss! Sell that Greddy intercooler on ebay and get good money for the name, and put that money to a good intercooler. It probably would be nice to put out an upgraded intercooler BHR!

Bryan@BNR

Brettus

iTrader: (2)

Bryan,
although the IC i have trialed was a cheapy - it was significantly larger 12x3 vs 8x21/2 for the greddy .
It did improve the pressure drop by about 1 psi but nothing like what i expected .
I'm thinking the problem lies in the pipework between the turbo and the IC
First you have a very tight 90 deg bend at the top of the turbo
then about 3ft of very small (2") pipework followed by a tight 90degree bend into the IC .
Sort this and the actuator and possibly a larger IC as well and we will start seeing 350whp + BNR upgrades .....


Forgot to mention also : the stock Greddy tubo inlet pipe is only 50mm . Seeing as the BNR inlet is 60mm + it would seem wise to upgrade this piece also .

Bryan@BNR

You would be suprised what you can get out of an intercooler pipe :D. I hope to see 350 plus! After that I think the product will have solid results and maybe turn this 280 RWHP into something actually impressive.

The turbo side boost gauge signal was after the 90 coming off the compressor housing so the pressure drop from that hard 90 isn't in the equasion.

Brettus

iTrader: (2)

Yes but this is only 2" !
I'm pretty sure if you measure the coss sectional area of the stock greddy intercooler tubes and compare with a dia. 2" pipe - the pipe will be smaller. Then you have the 90deg. bend .....

not in the equation as far as the 16psi is concerned but could still be a major barrier to making power - who knows what pressure is before that bend...... Have you seen the piece i'm talking about ?

MazdaManiac

iTrader: (3)

I think you might be misreading that.

I don't think they were simultaneously seeing 16 on one side and 6 on the other.

No intercooler produces a 10 PSI drop.

I suppose.
I only use cheap intercoolers.
Name brand intercoolers are just eye-candy.

I've used cheapies for every stage of my build over the past 6 years and every one had less than 1 PSI drop.

I think you might want to read up on how centrifugal compressors work.

Bryan@BNR

I have heard of 1200 RWHP on a 2.5" intercooler pipe. The turbo side intercooler pipe isnt as crutial as the upper intercooler pipe. A 90 degree bend on the turbo side isnt going to make a drastic change in pressure drop. I run just 2.5" on my RX7 on the turbo side. It is 3" on the upper tube.

Bryan

Brettus

iTrader: (2)

the bend is downstream from the compressor - don't see what you are getting at ...

Brettus

iTrader: (2)

hmmm - well the pressure drop has to come from somewhere . Just seems to make sense that it's that pipe given what I found with a bigger IC in place .

MazdaManiac

iTrader: (3)

A centrifugal doesn't pressurize the air - it accelerates it.
Every time you decelerate the air into a larger volute, you are increasing its effective pressure.

Everything after the compressor is part of the compressor.

Brettus

iTrader: (2)

ok - so there will be 16 psi before the bend as well ?

Bryan@BNR

About 10 or so years ago, I got this huge intercooler. I was just ready to put this thing in my RX7. I put it in and had a 1 bar wg spring in the wastegate. I coldnt get more than 4 psi out of it w/o a boost controller. The car was so laggy and whouldnt do anything. I put a different intercooler in and problem was solved. Also back in 1997, I bought a front mount off of an 89 Conquest/starion. I had John Meyers (pro stock motorcycle rider) weld 2" pipes on the tanks. He took it over to star racing and bench tested it. Flowed only 290 CFM lol. I put it in the car and at stock boost levels, the car only was making 1 psi of boost. Put the stock TMIC on it and it was running 7 psi. Stock intercooler went stayed on lol.

Intercoolers can only flow so much and cool so much. After the wall is hit, no more power. You can also have an intercooler that flows really well, but doesnt cool effectively.

I am not saying anything bad about ebay intercoolers. I have an ebay liquid/air intercooler in my FB. If you are on a budget, a good china unit is hard to compete with. BUT, the name brands such as Griffin, Garrett, and Spearco will have an edge on any of the china counterparts.

If you are looking to make 400 hp on a china intercooler, get one that is rated for 600. They are known not to flow as advertised.

MazdaManiac

iTrader: (3)

I totally agree.
The beauty of that is - The 600 HP Chinese intercooler is still less than $200.

However, many of the intercoolers on "eBay" and such are not made in China.
The guy who makes my custom intercoolers for me on the cheap also sells his stuff on eBay and he is in Pennsylvania.

Brettus

iTrader: (2)

Still not sure what you were getting at here .
I wouldn't have thought the type of compressor would change the way air would flow though a tube .
Every time the air is constricted in some way it must create extra pressure up stream of the constriction - which suggests to me a higher pressure at the turbo outlet than on the other side of that hellishly contricting bend on the top of the turbo .

Brettus

iTrader: (2)

The worst restriction to flow on the Greddy kit is the bend on top of the turbo . I believe this a big part of the problem guys are having extracting decent power from these upgrades.

Suggestion :
Bryan , when you do these turbo upgrades offer (as an extra charge) to machine off the flange at the outlet such that it is suitable to fit a 2" 90degree silicone coupler .
Then all we need is a short 2" extension pipe to fit to the existing tube .
The improvement from that alone will be huge .
I plan to do this when my turbo needs rebuilding but that might not be for a while .

MazdaManiac

iTrader: (3)

What makes you think a 90° silicone coupler is less of a restriction?

You still aren't getting how the diffuser in a turbo works.

I use a 135°, 2" bend at the outlet of my turbo. It is absolutely no restriction (as the pre-bend pressure is exactly the same as the pre-intercooler pressure).

Brettus

iTrader: (2)

have a CLOSE look at the pic i just inserted into the above post . That piece is WAY more restrictive than a 2" bend.

MazdaManiac

iTrader: (3)

No. It. Isn't.

Diffuser. Look it up. Learn it. Understand it.

Have you ever "run the numbers" on the volute and how compressor A/R works?

Brettus

iTrader: (2)

I don't need to understand any of that and don't get why it even relates to what we are discussing .

What I do understand is that if you put a restriction in front of a turbo - it will reduce its flow , (unless you raise the boost pressure).

I suppose you are going to tell me you could have it blow through a straw and produce the same flow ?