I fitted a Plate and bar frount mount a while ago, and eversice the car feels flat, also wont boost like it used to. If i crank the boost controller up, it will boost up over 14 psi at low revs (I've got a boost limit that kills ignition if boost goes over 15), but then it drops to 10psi, and while drivng with the pedal hard down, ie on the drag strip, if I crank the boost controller open, it just won't give any more boost than 10 psi...... I'm going to try the old BB intercooler again, but its a bit of a bitch that I paid $1000 for this custom cooler, and the car definatly lost power. I went from 14 flat to 14.5, and it's taken heaps of work to get it back into the low 14's again, so I figure if I can get the boost back again, I should be able to break a 13. The turbo is a T25, and basically waht I want to know is if the Plate and Bar design is just too restricted for the little turbo...??? I was even thinking of a water to air, to keep the intake tract a bit shorter, the cars used for drags a bit.

What's a plate and bar cooler? What car do you have? Why don't you use a stock intercooler? You are in NZ right? Get a 200SX stock sidemount and front mount it or something.

Maybe there is a leak in the cooler or you have excessive pressure drop. I would check you boost connections and for leaks though.

Larry

You probably are losing a psi or two of boost with all the extra pipework.

Its a NX-R (nx2000 to you) with a BB Sr20det, I had the BB cooler frount mounted before, and I could dial up 12 psi easy anytime. The new cooler is mounted with the same pipework, just shortend to fit the longer cooler. i was told the BB cooler was poor flowing, so I contacted a company here that specialises in heat exchangers of all sorts. They have made quite a few coolers seen in a number of performance mags here, so hey I figured these were the guys to deal with. When I spoke to the guy on the phone and told him what I wanted he asked if I wanted tube and fin, about $700, or Plate and bar, about $950. I said whats the diff, and he says the plate and bar is "better". Silly me I didnt ask why is was better, but apparently I have now found they flow less, but cool heaps better. But what I think cold be the problem is the T25 just cant push enough air at high revs, due to the small size of the turbo??? I've fitted a pressure gauge before the cooler, and at 10psi at the manifold, the pre intercooler pressure is about 17psi, which means the turbo is working to produce 17.... I've been told they are not to shit hot for reliabilty over 14 psi.

How do you lose pressure from more piping? It just takes a little bit longer to build pressure. Kiwi, a 7 psi pressure drop is a LOT. Check to see if your connections to the IC are not leaking. Also, the IC itself might be leaking. What size piping are you using? You should be using 2" piping.

yeah, it is definitely leaking.

lemme guess, the car is running pig rich too right?

Originally posted by 92SE-R
Also, the IC itself might be leaking. What size piping are you using? You should be using 2" piping.

Sorry for getting off the topic, but quick question for you Terrin. How do you determine what size piping you should use? I assume it depends on the turbo size and amount boost you run, yes? Whats a good rule of thumb?

I've got an Avenir det with the stock T25 (waiting on JWT for ecu, but you know how that goes) with the forge frontmount IC, and was planning on using 60mm (2 3/8"), am I in the right ball-park?

-thanks

Since I just told him to use 2" for T25, that would work good for you too since you ALSO have a T25.

i have the exact same setup, avenir T25 and forge IC, and i used 2" piping. go with the 2", it is easier to fit as well.

took me to a 12.9@107 with only 10 psi.

No kidding. :D What I'm looking for is a general guideline of what size piping should be used for a corresponding tubo size, and also a little insight as the reasoning behind that.

Originally posted by HotshtSR20
i have the exact same setup, avenir T25 and forge IC, and i used 2" piping. go with the 2", it is easier to fit as well.

took me to a 12.9@107 with only 10 psi.

What do give up using a larger size on a smaller turbo? More lag?

since it is pressurized and being forced into there, you dont need the large piping that NA cars need (except for your inlet pipe, which should be at least 2.5"). 2" will mean less volume for the turbo to fill in the intercooler piping before the manifold is pressurized, which will mean less lag.

you will not see any real gains by going to larger piping unless you clear the 350 whp mark, IMO.

also, 2" is easier to package under the hood.

I'm thinking your intercooler isn't good for your small turbo. It might be good for bigger turbos that puch more air, but since you have a pretty small turbo, it's probably very detrimental to you (I remember reading somewhere that sometimes there is a trade-off between better cooling efficiency and pressure drop in Intercoolers, or maybe it was how much flow vs. pressure drop).... and maybe you might also have leaks (I'm not expert though, these are just my thoughts).

Hotshot SR20, WOW, very nice, you ran 12's with a T25, I was hoping to run low 13's with my T25 (but now I'm hoping to get a gti-r manifold and turbo for cheap).... hmm, it seems 12's can be a realistic goal for me then if I do use the T25 :D

Its not running rich, I get 600km out of a tank of gas, as opposed to 450 from the NA engine. But then its got a full house programable ecu, witha hand controller in the cab that I can monitor mixture and tune on the road. I put a air fitting on my intake pipe, ie before the turbo, and used a regulator on an air compressor to pump the whole lot up to 12psi, no leaks.... I'm going to fit the BB cooler back on the frount, it just needs some extensions on the ic pipes to refit.
Steve, how the hell did you get 12.9 with t25????? what sort of tires are you running? Have you got the car fully stripped out? The only guy here doing those times is running a t28 with just a seat and dash in the car.
I am running 2.5 " pipes, mainly because the cooler had this size pipe, and the pipe off the turbo was 2.5", I guess this gives some lag, but even though it doesnt boost well at revs, it comes on boost real well, like by 3000rpm it can peak at 13, but then drops back to 10 as the revs rise.

full interior, tools in the back, and my 2 kenwood excelon amps (25 lbs each) still on the back of the rear seat.

MT 14x8x20 slicks on B13 wheels.

how did i do it? easy. rev to 5K rpm, drop clutch, shift at ~7500 in every gear, slow down, stop, collect time slip.

mods: Avenir T25, forge motorsports 24x6.2x3.5 IC with 2" piping, open 2.5" mandrel downpipe, tomei cams, JWT computer. had the timing bumped down to 14 degrees because i would detonate with the cat in there, and i forgot my timing light.

I'm still amazed, mine ran a 15 flat with the subs and spare tire in the back. Problem I have is my 60 ft times are around 2.3, because I cant run slicks in road class. a friend of mine was looking at importing some Nitto tires from US, but I dunno how much it will be to get them here. I've got some race tires, but they are only 195, as opposed to 205 I use on road, and so far the times between the two types are about the same. What sort of boost are you running?

If you want to drag race do yourself a favor and get some Mickey Thompson slicks. Get the 20X8X14 on stock rims and you'll cook. You can tell by Steves 1.9 60 foot times that there isn't a problem with traction at all. Great times Steve, I know it made a friend of mine with a GST all jealous. Hook 'n Book

Well right now there is a group deal for some Nitto's, look in the for sale forum, but I'm not sure if it will fit your stock rim... Also when you drag race, you want to take out everything you can that can weigh down your car.. including those subs and amps... at least the subs, subs and the box are usually heavy and pretty easy to take out and put back. Also your spare is easy to take out. But 2.3 60' times are pretty good I think... my first time running I got 2.2 60' times on street tires, but I haven't been able to get them again :( ... maybe not enough practice

do it right, buy once. a penny saved is a penny spent tomorrow.

buy the slicks, they are a little more, but at least you won't have to buy them in the future. they will most likely last longer, and give you better times. for the motor, 14x8x20 Mickey Thompsons would be perfect. i will likely get 15x8x22 MTs, as i am turbo.

Chris, i know what you mean. all the DSM guys i have talked to were utterly amazed that i got such a good time on such a (comparitively) small amount of boost. there was a guy there with a large housing 16G running 18 psi, and he was running the EXACT same times as me, down to the trap speed, within a couple of tenths!