DCZ Posted September 13, 2006 Share Posted September 13, 2006 Been searching the archives trying to edumacate myself and my head is spinning. I admit - I'm confused! I have a line on either of two turbos for an excellent price and am not sure if they would work for me. my engine - stock L28t, p90a head (hyd) in a 73 240z my goals - solid 300 hp, ~15psi, intercooled, megasquirt turbos (sellers description) supposedly Garrett T3/T4 hybrid #1) 3" Inlet 2" outlet .50 A/R stage 3 compressor wheel .63 A/R turbine .57 trim. Will bolt up to a t3/t4 manifold has a wet floating bearing 1/8 oil inlet 5 bolt exhaust flange. #2) .50 compressor housing .84 A/R divided turbine housing .57 stage 3 compressor wheel. It also bolts up to a t3/t4 manifold. Would either of these turbos be a good choice for me or am I missing something? What would be advantage/disadvantage of one over the other? I am assuming I would have to go external wastegate with either(?). Is there any other info I need to make a decision? Thanks for any advice. I'm new to turbos so talk to me like you would a six year old. Then dumb it down Quote Link to comment Share on other sites More sharing options...
Bernardd Posted September 13, 2006 Share Posted September 13, 2006 I would tell my six year old to call James Thagard aka 240zturbo. Quote Link to comment Share on other sites More sharing options...
DCZ Posted September 13, 2006 Author Share Posted September 13, 2006 I would tell my six year old to call James Thagard aka 240zturbo. I would talk to James if I were going to buy from him. I don't want to waste his time. I am asking about these specific turbos because they are available at a rediculous price so if one will work for me I will buy it now, even though I am not ready to install it. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted September 13, 2006 Share Posted September 13, 2006 T4 compressors aren't (to the best of my knowledge) named in stages. Thats the turbine wheels. T4 compressors are broken into two categories B and E, and all listed here: http://www.turbofast.com.au/flowmaps.html Are you getting confused with the `trim' series? TO4E series are named in trim numbers, with a 57 trim being quite common. The way you have written it sounds like the turbine trim. T3/T4 hybrids I believe were originally developed for tight-ass people who didn't want to have to go external wastegate, but wanted more compressor flow. Indeed most T3 housings are internally gated (with some exceptions, the GT35XXR series for example), so you shouldn't need a new manifold/ext gate. Tell us correctly and precisely what you are talking about and we'll go from there. IMHO 0.63 T3 turbine housing is overly small, but probably still enough to meet your 300 (fw/rw?) hp requirements. Dave Quote Link to comment Share on other sites More sharing options...
DCZ Posted September 13, 2006 Author Share Posted September 13, 2006 Thanks Dave, Sorry for the confusion, the turbo descriptions are right from the seller and maybe that is adding to my misunderstanding. From the link you provided it seems that these turbos are probably T04E with 57 trim (I'll try to verify that). I understand what A/R is but I don't know how it affects the choice of a turbo. It seems from my reading that a larger A/R will support higher flows (therefore HP) at the possible cost of more boost lag (is this true?) I played around with the formulas in one of the links in the Turbo Sticky and got an estimated air flow rate of 27 lb/min. This would put me right in the "sweet spot" of the T04E 57 trim turbo map. I should play around with more number estimates to see if that 27 lb/min is a good number to use. As far as internal/external wastegates go, I have experience only with my current T3 internal wastegate. If/when I upgrade, I don't mind the extra cost/work for an external wastegate if it will improve the final result. I currently have a 2.5 inch downpipe so an upgrade may be in order anyway. It seems to me that the two turbos in question differ only the the turbine A/R, with the larger .84 A/R turbine having a split housing, which does not gain me anything with an L28 AFAIK. Now, the .84 vs .63 will most likely make a difference, but I don't know what that would be. Any comments/discussion appreciated. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted September 13, 2006 Share Posted September 13, 2006 DCZ, Spot on. A larger A/R housing (in a given family, ie T3 or T4) will mean more flow potential, but also more lag. Note when I say lag I mean lag, not boost threshold which (if you are driving hard) only really matters once. The rule of thumb is 1lb/min is good for around 10hp. So I would be looking at maps that are good for atleast 30lb/min, more like 35 to give you room to play if you so choose. Largest, smoothest flowing dumppipe you can get is always going to be a good thing. Dave Quote Link to comment Share on other sites More sharing options...
sweetleaf Posted September 13, 2006 Share Posted September 13, 2006 Give us a link to the sellers description. If they are the cheapy ebay turbos, I would stay away. Read some posts, you'll see what I mean... I'm using a T3/T04E 57 .. It's a great turbo depending on the rest of your setup but when I have the cash I'll upgrade to a GT38 probably.. Quote Link to comment Share on other sites More sharing options...
DCZ Posted September 14, 2006 Author Share Posted September 14, 2006 It is advertised in a local classified. Sellers description is in my first post. Supposedly new, Garrett T3/T04E. Looks like it's worth checking out. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted September 14, 2006 Share Posted September 14, 2006 Check that there is a Garret tag attached to the CHRA. Get P/N, ring Garrett and ask what it is. Dave Quote Link to comment Share on other sites More sharing options...
DCZ Posted September 14, 2006 Author Share Posted September 14, 2006 Good idea! Why didn't I think of that (DUH!). Thanks Dave you've been a big help. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted September 14, 2006 Share Posted September 14, 2006 NP. Dave Quote Link to comment Share on other sites More sharing options...
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