Here is something I think some of you might find interesting. I ran across the compressor map for the stock 86/87 GN turbo.

http://www.turbobuick.com/forums/turbos ... r-map.html

If you plot this map the same as we've plotted the others you'll see that at 1.54PR(8psi) and 300hp(30lbs/min) that its completly off the chart to the right. Also if you all will notice the low efficiency of the compressor even if you were smack dap in the middle you only getting 71% efficiency. Of course this turbo is a victim of 80's techology hence the low efficiency but if I am reading these maps right now( which I think I am from Runvs' explanation), this doesn't look like a good turbo for a 225 running 8lbs wanting 300hp. Don't get me wrong this turbo in theory can support almost 400hp BUT you'd have to run well over 14.7psi to do it and again the efficiency just gets worse. 400hp is something like 65% compressor efficiency. An intercooler would help some but it would have to be pretty efficient to make a difference. Infact looking at the maps Runvs put up, the TO4 is a MUCH better turbo for the 8psi/300hp goal. Granted its not right in the middle but its close at 75% efficiency island.
And it also looks like the 8psi/300hp intersection on the HX30 is right on the 76% efficiency island. The colored area Runvs put there seems to be reading 8psi/150hp so I am not sure how that works perhaps he can explain that. Anyway I am pretty sure I am reading these right. Runvs put it in very simple terms. If I am reading these right, who else was suprised about the GN turbo map? I was. The 60-1 seems to be PERFECT for making 300hp at 8psi according to its map. Just for fun I looked at a map for a T76 and according to it's map it will make 400hp+ at 8psi [/img]

At the last dyno session with the tbo348 I made 253rwhp and 338rwtq. This was with a stock motor and 23psi of boost. It was intercooled and with meth injection. I still had the stock exhaust manifold and a 2.5" exhaust. I think there was more HP to be found.

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11.02 @ 120.56
http://www.youtube.com/watch?v=EAxRmoDgsdY
Chassis dyno
http://www.youtube.com/watch?v=wd6hFGzLJMc

Just wanted to say my name is Wesley by the way Thought I would be polite.

However, I think Turbocuda has got his information on which turbos to choose. I'm glad he found the original GN map and can see what it is or isn't. I just grabbed a map from turbonetics and looked at what I thought it would be close too. Looks like it might be the winner! Anyways, having learned a few things myself, I think this is a worth while thread. I'm going to try and re-do my calcs and pictures. The first time was really quick off my notes and using Paint on the maps.

Edit: Calcs and maps fixed, a little better numbers. Had to re-read for VE correction and temps.

A couple more calculations based on higher boost and VE. The book states about 75-80% for OEM and street engines.





Looks like about 10lbs should get you to your 300hp goal with a little head work and a good cam. Take a look I doctored up some of the maps to help people visualize. Hope it helps, or I can delete if they take up too much space.

Warner, Mark. Street Turbocharging: Design, Fabrication, Installation and Tuning of High Performance Turbocharger Systems. New York: HP, 2006. Print.

Wesley very nice to meet you, my name is Brad. Guess I forgot to mention that also:) You have been such a huge huge help to me in understanding these maps. Thank you very much for that. I really didn't think I would ever understand them. I think a lot of us have learned something or another with this thread which is great. I also want to thank everyone else who gave advice in this thread and shared their knowledge with me I am very grateful.

I would be very interested to know what map you found at Turbonetics. That was one of the places I looked at maps which is where I found the 60-1 map. Looking at the HX30 map and understanding how to read it I believe I understand where you were coming from. The HX30 I believe is still a great turbo for a 225 but at higher boost is where it really shines. Its not that I think it wouldn't work at 8lbs and I figure with head and cam work it would spool pretty quickly to 8lbs which I had planned on doing all along was head and cam work.

Also Wesley if your interested, I found a VE calc online that I can point you towards so you don't have to guess for each engine. I put in the 225's specs and the calc said the engine has a 73% VE NA which is a lot lower that people assume. So for fun if you wanted to use that VE with your calculations and see what you come with it would be interesting. I'd like to see how much of a difference it makes.

Shaker I think you have proven a good point with your dyno numbers. With a stock 225 you had to run 23psi, run and intercooler AND methanol injection and you made 253rwhp. I had mentioned in my past post with the map that 300hp COULD be had IF you ran over 14.7 psi but I think its proven the stock map to be true, at the very least that with my goal the GN turbo wouldn't give me the 300hp without running over 23psi with an intercooler and meth injection. In your dyno run your running 2.6pr which is the max the stock map shows but mentioned it will go to 4pr. It could be possible that if your slant was modded like I plan to do mine that you may have hit 300hp but I wonder if it would be at 8psi? The GN guys say the stock turbo will support 375hp, even the map says 37lbs/min max flow.
Shaker I don't want to sound like I am running you down or telling you that you made a wrong choice because I am not saying that at all. But I think if I came up with the money, the 60-1 is what I will get. I may still run a GN turbo if I found one cheap enough. Does anyone have an idea what a 300hp slant would run in the 1/4? Theres a lot of variables I know but just an idea of what it would run in a 66 'Cuda?

Glad to see you enjoyed my work. I just reposted on the old note so if you haven't rechecked them than I would do that and see what the maps look like now.

The HX-30 would be fine if you got it cheap. My impression was that it was more affordable to get the Grand National turbo, however, scurrying across e-bay I don't think I care about either or. I would save the money and get the T04E 50 trim that would suit this particular build well and maybe skimp or wait on another part. I looked at the 60-1 and here is what I got...



So choose a way, I think at this point any of the turbos will work great and get you around your goal quite well. You will have more conerns about cost and tuning than which of the turbos we have talked about be best. Last, for the VE I was going off of the book figuring his calculations might be best. His example of a Honda engine has a VE of about 80% stock. Anyways good luck and will look forward to your build and tuning questions.

I ran high 12s with skinny tires in a 3,365lb race weight 70 Dart and this combo. I'm sure a better exhaust system would have helped a lot.

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11.02 @ 120.56
http://www.youtube.com/watch?v=EAxRmoDgsdY
Chassis dyno
http://www.youtube.com/watch?v=wd6hFGzLJMc

Shaker that is very impressive! Ok so lemme see if I got this right. You had a completely stock 225 and simply added a GN turbo, ran 23psi with an intercooler and methanol injection which gave you 253whp and 338wtq and with full weight of over 3300lbs with skinny tires and ran high 12s? What gear ratio are you running in the back? Transmission? Any suspension mods?

I am not calling you a liar or anything but that doesn't make any sense to me. LS1 T/A's and Camaros run low 13's even high 12's stock but it took over 300hp, a 6 speed tranny, something like 3.40:1 rear gears bigger tires that you ran and just all around new technology with about 3400 to 3600lbs weight. Not only that but I've heard for years that to get a slant into the 12s even the 13s takes a real short gear set in the back, slicks, a built engine, a tranny with a stall and a big weigh reduction. If you say you did then you did but you see where it doesn't make sense though from my examples right? If thats all it took to get a slant into the 12's I'm wondering why everybody and their brother isn't doing it.
At any rate that just got my hopes up alot for my build. If I can get 300hp I should be deeper into the 12s that you were with the combo you mentioned. Now I wanna get this project started even sooner

I added shimmed 340 valve springs, head studs, copper head gasket and o-ringed the block. 2.76 gear & 904 with low gear set. HD leafs. 87 GN Turbo & exhaust manifold.

Below is a vid of the high 12 from 2007. Since then, the car went as fast as a 11.77 @ 116 with a different turbo, exhaust and more boost... all with the same engine before a piston failed.

http://www.youtube.com/watch?v=pPe_vHwZsF4

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11.02 @ 120.56
http://www.youtube.com/watch?v=EAxRmoDgsdY
Chassis dyno
http://www.youtube.com/watch?v=wd6hFGzLJMc

The Slant 6 responds very well to boost. Shaker has the guts to put stuff together and try it. Also, almost EVERYONE overstates their HP numbers.

Mr. 630HP Slant 6 in Aussie has said the turbo he has is "way too big" for what you should run on a Slant, but every time he makes it bigger, it makes more HP and runs just fine.

Lou

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Home of Slant6-powered fun machines since 1988

Sweet so maybe my slant won't have to be "built to the hilt" which I hadn't planned on putting a lot of money into it anyway. I was just gonna do a few things and just take it for whatever it gave me but apparently I'll have a lot more than I thought. How much power before the pistons crap out? Don't need to worry about the rods and crank right, just the pistons? I still have no idea where to put my intercooler. Only place I could put it would be under the bumper like some of you have done but I'd be afraid of rocks or other road debris would mess up my intercooler. I still may try to get an intercooler to fit behind the grill but I am wondering if it will end up being too small to be of any use and actually just end up hurting performance. Shaker what carb were you using? 2 barrel of 4? I'd like to use my 2 barrel setup n maybe upgrade to the bigger 2 barrels. I read somewhere that someone actually made more power with a 2 barrel than with a 4 and attributed it to possibly being increased velocity. What do you guys think?

From what I can say about boost it is amazing ho well engines in general respond to them. I mean when you build N/A (and maybe nitrous) you are having to sacrifice street ability to get into fast times or go with a v8. Than on top of that you are at the mercy of what your engine builder or machinist is capable of doing. I want to build this 170 "to the hilt" kinda go big or go home. However, knowing what I know now about slants a 819 cam and a nice blueprinted engine is all I would worry about. That simply means balancing and cleaning up the engine with the die grinder where necessary. This also means skipping H-beam rods, forged pistons (might still suggest those), a big cam and such. Get a good turbo on it, kick it to 10lbs, and spend the rest of my time tuning.
I think this would be cheaper than some N/A options ie strokers, aluminum heads, billet parts; thus leaving money for tires and four links (Don't ask, ok maybe go ahead)

I used a 600 Holley DP. Drivability around town and on the fwy is good. Keep boost levels moderate and more importantly a good tune and it will live for a long time.

_________________
11.02 @ 120.56
http://www.youtube.com/watch?v=EAxRmoDgsdY
Chassis dyno
http://www.youtube.com/watch?v=wd6hFGzLJMc

A good tune is the most important thing. You must keep it out of detonation. I broke more then one piston (even forged) at 8-10 psi, because of a poor tune up.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

So how hard is it to tune with a carb? Shaker I read how to make that bracket you were talking about and I am not sure I can do it. I see myself ruining many power valves. If I could find one already done or find someone to make one for me I'd be more than happy to pay for it to make sure it was done right. Something I read on their site was that one guy on there made one and it ran WAY to rich. He said it was running in the 1.03 type rich. I don't know if he ever fixed it or ever found out how and they said something about using different power valves to tune the carb. Its all pretty well over my head I don't have alot of knowledge on carbs and I've only rebuilt one so ya experience is limited. I'd like to be able to run the numbers you were talking about and still get decent mileage. Dunno if its possible without EFI? Also I noticed you mentioned that you switched manifolds? Did I read that right? If so did you switch to a custom header type or what? I will probably use the stock manifold. I ported mine the last time I had it off so that should help granted its not a high flowing header type. I ported my super six manifold too, well gasket matched it anyway. Anybody have any opinions on using the BBD? Would it be harder to tune?