quote Originally posted by rjblaze: How does something like this: http://cgi.ebay.com/ebaymot...IT&item=390004694697 look for a 3.4L w/Comp 260H cam and Focoa headers? Too big? Too slow too boost? I figure the twin-scroll would spool a bit faster with the proper cross-over set-up. What do you think?

you need the compressor map for that turbo before you can make any decisions. What are the exact specs so you could cross reference it with another turbo to get an idea. that unit is also big, you will be surprised at how large it is.

I certainly do not believe it's 400HP rating. Also, be warned most china made turbos like that need to be fully disassembled, cleaned, and re-assembled.

Finally got around to reading the tread and following most of the links. Lots of good info contained here. Kudos to all contributors

I also want to thank whoever it was who posted the link to the Squirrel Performance - Turbo Calculator. This was a great tool for plotting airflow on various compressor maps. I've been messing around with sizing a turbo for the 3.2, and based on the formulas here http://www.turbobygarrett.c...r/turbo_tech103.html , and the compressor maps here http://www.turbobygarrett.c...s/turbochargers.html , I'd pretty much settled on the GT2860RS (the Disco Potato) as the best match.

Assuming the link function works, here's most of the assumptions used in plotting/calculating airflow using the Squirrel Performance calculator: **Edit again - Linky no worky, so here's a picture**


Air temps were calculated using a 68% efficient W2A intercooler with 80*F intake air temp and 70*F ambient air temp. VE numbers were guesstimated, but as long as they're within +/- 10% it doesn't really affect the results much at all.

At any rate, here is how things look on the compressor map: ht tp://www.squirrelpf.com/t...7=29.8&product_id=32 It looks like the engine is in the most efficient areas of the compressor map for much of the RPM range. Also well away from surge and choke points.

What I haven't really seen anywhere yet is a good explanation on how to read the turbine map, or how to choose an appropriate turbine A/R ratio. All I know is that lower A/R's spool earlier, but create excessive back pressure at higher RPM's. I found a reference that the .86 A/R will allow the turbo to create full boost by 3400 RPM, which is probably OK. Here's the turbine map for the two possible turbine housings:.


Does anyone have a reference on how to interpret these?


Cheers

[This message has been edited by TiredGXP (edited 01-01-2009).]

Anyone have any info on air-Water intercoolers?

Would this be a way to put a intercooler in a hot place (engine compartment with no air flow) and then run a pump and water lines to a radiator in front of the car and get the same effect? I am looking at options to get decent air charge cooling (Drop it to at least 160 degrees) without having to route big 3.5" air lines all over the place. Installing a pump and smaller water lines are far easier to do.

quote Originally posted by timgray: Anyone have any info on air-Water intercoolers? Would this be a way to put a intercooler in a hot place (engine compartment with no air flow) and then run a pump and water lines to a radiator in front of the car and get the same effect? I am looking at options to get decent air charge cooling (Drop it to at least 160 degrees) without having to route big 3.5" air lines all over the place. Installing a pump and smaller water lines are far easier to do.

I've read a good bit on them and it's a bit more involved than just installing the system. It's ability to cool effectively depends on the volume of the system and water flow. In simple terms the system must contain enough capacity to exchange heat at a greater rate than is being put into the system which means you need to calculate the estimated heat generated by your engine system vs. the capacity of the air to water intercooler to remove it, since unlike the air to air you are dealing with two heat exchange points. I have come across quite a few entries over the net stating that it's most effective in drag cars for brief cooling ability above 100% efficiency using ice. The exchangers are not on the small side though I did see a tube style from Silicone intakes. The system was used stock on the Syclone/Typhoon, Ford Lightning and the Supercharged cadillac but I imagine it's a pretty good size system given the size of those vehicles.

[This message has been edited by Joseph Upson (edited 01-02-2009).]

quote Originally posted by timgray: Anyone have any info on air-Water intercoolers? Would this be a way to put a intercooler in a hot place (engine compartment with no air flow) and then run a pump and water lines to a radiator in front of the car and get the same effect? I am looking at options to get decent air charge cooling (Drop it to at least 160 degrees) without having to route big 3.5" air lines all over the place. Installing a pump and smaller water lines are far easier to do.

I came across this article recently: http://www.mr2supercharger....tercoolingPage1.html Page 5 also has a bit of discussion specific to W2A IC's. The same author has an interesting piece about intercooler math on AutoSpeed: http://autospeed.com/cms/A_109789/article.html (If you haven't seen it, AutoSpeed is an Aussie automotive e-magazine. A number if interesting articles in the DIY and Tech archives).

The one thing that really caught my eye was the statement that a turbo car is only on boost about 5% of the time, and that full boost situations rarely last more than 15 seconds (well, except maybe climbing up the passes in the continental divide). I had a Chrysler Daytona 2.2 turbo from '84 through '92, from what I recall, the 5% on boost figure is about right, no boost when cruising around at a steady speed, just on acceleration/hill climbing. The interesting thing about this 5% "boost duty cycle" is that the 95% of the time the turbo is not adding heat to the IC would allow more than sufficient time for the radiator to bring the water temp back down between bursts of boost.

After a bit of searching I came across this info on Spearco W2A intercoolers: http://www.racetep.com/tneticatolic.html . The 2-252 unit is the smallest W2A unit shown, and has a data sheet showing charge cooling results for 275* inlet air at 15 PSI boost and two different airflow rates. A little bit of math shows that the IC efficiency using 110* water is 81% at 270 CFM and 52% at 450 CFM. Since a Gen 1 3.2 is not going to pull anywhere near 450 CFM, this is probably a good size intercooler for that application.

** Disclaimer - what follows is just playing with math, doing a bit of bench racing**

I wanted to see what the efficiency curve of this IC was, and get an idea of the impact to power generation on a gen 1 3.2. The first step was to convert the IC airflow data from CFM to lb/min. Made the assumption that the lower the mass flow, the closer to the water temperature the air would be. In theory then, at 0 lb/min the air in the IC is the same temperature as the water. I called this 100% efficiency (even though the IC is probably acting as an interwarmer at that point) for purposes of generating a trendline. Anyway, here's the graph:



Key assumption for what follows is that the trendline generated above is applicable to different air temp and pressure values - the efficiency is dependent only on mass air flow through the IC.

Other key assumptions are:
- each pound of airflow generates between 9 and 10 HP at the crank (used ~9.4 here)
- that airflow is dependent on VE regardless of boost level. Pushing air instead of sucking it doesn't increase the ability of the engine to flow CFM

I used the following VE values for all scenarios:
RPM - - --VE
2000 - - - .8
2500 - - - .83
3000 - - - .85
3500 - - - .85
4000 - - - .89
4500 - - - .825
5000 - - - .76
5500 - - - .683
6000 - - - .58

SANITY CHECK: A stock 3.1 generates 180 ft-lb of torque and 140 HP, so with a bit of gasket matching, port clean-up and exhaust manifold work, 150 is easily reached in a N/A engine. Using the VE and HP per pound of airflow above, you get the following:


The assumptions result in power and torque numbers that are comparable to stock, the shape of the torque and HP curves may be off a bit, but good enough.

So if you apply 10 pounds of boost to this theoretical engine, this is what things look like:


If the IC efficiency curve above has any bearing on reality (I think the curve shows too much efficiency) then using this intercooler results in :

This looks like about 90* reduction in charge temperature and 25-30 more HP and Torque as compared to no intercooler.

Based on the prices on the Top End Performance website, you're probably looking at $1,300 or more to build an IC set-up with all plumbing (using new parts). Seems a bit steep, but then again, it might just keep detonation at bay and save the engine.

Cheers

I figured this would be a good place to link this thread to as there has not been many responses lately, but it does contain some good info about turbo's.

https://www.fiero.nl/forum/Forum2/HTML/097552.html

Now my question, does anyone know the size of the 5 bolts that attach the internal wastegate assembly/exhaust pipe flange to the turbine housing?

Bumpity.....bump

Well, Garrett uses M8 x 1.25 bolts on their 5 bolt flanges. If you zoom in far enough in the diagram in this link http://www.turbobygarrett.c..._15_771847_1_new.pdf you can see the bolt size. I didn't re-read the thread you linked here, so if you don't have a Garrett turbo, maybe you can find a similar set of flange drawing or your turbo.

Cheers

Thanks GXP, I appreciate the info.

Next question, anyone know a good place to research a possible "map" for and "unknown" compressor. I know I have a 57 trim T3/T4 with a .63 A/R turbine. The only other information I have is some numbers stamped on the compressor housing...looks like a serial number. There is no brand name (such as Garrett) on the unit anywhere. This was an e-bay unit (still new) I got from a forum member. I do plan on taking it apart to check it out fully and have the turbine housing Jet-Hot coated, but I would like to be realative sure this is the unit I want to use on my future 3.4L pushrod conversion.

thanks

Charging.....charging.......charging.......CLEAR! ZZZZZZZZAAAAAAPPPPPP!

Just a friendly defibrulation(?) for any more possible input!