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Post by 76turbohatch on Mar 27, 2008 22:18:08 GMT -5
Hey guys I'm new to the forum and recently acquired a 76 1.6 chevette 4-speed and I'm wanting to rebuild the engine and put a T25 turbo on the 1.6. I'm looking for any suggestions on how to or parts to use, I'm pretty much starting from scratch. I've heard something about straight runner head is supposed to be better, how do I know if I have that, or is there something better. Any suggestions are welcome. Thanks.
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Post by DOCTOR FIELDS on Mar 28, 2008 8:48:36 GMT -5
For cylinder head identification, look under Tech Tips in this section.
Hydroili might be able to help you with the turbo setup.
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Post by hydroli on Mar 28, 2008 20:08:51 GMT -5
I suggest you to go read some threads if you're not familiar with the chevette engine. It maybe won't tell all you need to know but it's a good start. After this, if you have questions, feel free to ask, there's always someone ready to help here.  |
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Post by hydroli on Mar 29, 2008 10:05:42 GMT -5
...A few things important to know is, how much you want to spend on this thing, if you want to go injection or carburetor, what you're expecting as a result or how many horses you want to build... every details you're already fixed with will help to give you helpful indications. With a carb you can go draw-through or blow-through (I choosed blow through). Each one has down sides and qualities. Draw-Through is simple to tune because the air density is always the same at the entry of the turbo. With this setup you're limited on how much power you can build with a specific turbo. There will be a little delay between the pedal and the engine response, but it is simple. Blow-Through is a little more touchy to adjust because, as presure raises, there is more oxygen by volume than it is at atmospheric pressure. To compensate, you'll have to richen up the mixture. An other important thing is that the fuel pressure wont be high enough. You'll have to go with an electric fuel pump and a fuel pressure regulator that will feel the manifold pressure (they are cheap on ebay). Here are some articles I found on chevette turbo. Draw through turbo chevette: i266.photobucket.com/albums/ii251/HydrOli/Chevetteturbo.jpgi266.photobucket.com/albums/ii251/HydrOli/Chevetteturbo2.jpgTurbo injection chevette: i266.photobucket.com/albums/ii251/HydrOli/chevette.jpgi266.photobucket.com/albums/ii251/HydrOli/chevette001.jpgi266.photobucket.com/albums/ii251/HydrOli/chevette002.jpg |
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Post by 76turbohatch on Mar 29, 2008 10:36:40 GMT -5
Thanks guys for all the input. I'm looking to go with a Rochester 500cfm 2bbl and make it blow through. I was curious if anyone made bottom end parts to make the motor stronger. Or for that matter, just any good parts period as far as engine parts go. I also am going with a Lazer 282 cam, anyone know where to get valve springs n such that will accommodate that? I have a little dyno program on my computer and with the cam and the 500cfm 2bbl and head work with the turbo, this little mean motor should hypothetically put down 170hp 130lbs. I would be extremely happy to hit or exceed these numbers. If anyone has any ideas on how to make this motor better, i.e. more hp, torque, or just strength lemme know, this will be an everyday driver when finished (gas prices).
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Post by hydroli on Mar 29, 2008 10:59:09 GMT -5
If you go in the topic "Hp numbers... Any dyno run?" You'll have a good idea of what can be done without a turbo.
Here is a video of a turbo setup making 250 hp
Here is a looong video showing details of a well done turbo buildup... second half is more intersting.
They sure show a lack of originality regarding music taste but, they show interesting stuff!
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Post by hydroli on Mar 29, 2008 15:24:34 GMT -5
I think that 500 cfm, is a little big for a daily driver.
You will rev around 6500-7000 Rpm max with the 282 cam and your engine is a 1.6L engine so no need for such a carb. Big CFM numbers will only help to rev high. I personnally choosed the weber 38-38 and I just hope that with 390 CFM it won't be overcarbed. Stock carb flows 245 cfm. (source: wikipedia, weber 32/36 carburetor)
Also, keep in mind that in one cubic feet it will be twice as much air than in the same volume when pressure will be twice as atmosphere. At the end, it will pass more than what your carb normally flows through the same holes.
If gas price is a concern for you I would go with something smaller, plus, an overcarbed engine won't be as drievable as what you're looking for with a daily driver.
Another thing is that 500 cfm beside the T25 Turbo is not a well balanced duo, from my point of view... You should compare the area of the two carb's holes with the area of the turbo compressor's hole to know what to do. 3.1416 x radius x radius will give you the area of the holes. Comparing hole's diameters won't give you a good idea of the compatibility between both, you must calculate the area.
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Post by 76turbohatch on Mar 30, 2008 2:23:58 GMT -5
Thats all really great info guys, thanks. I'm trying to find some valve springs that can handle .455 lift cam at about 7500 rpm max if possible. Anyone know if I can get any kind of performance valves/springs or if stock will work, which i doubt, at least on the springs. Again thanks for all the info, I'll make sure to not over carb my motor.
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Post by DOCTOR FIELDS on Mar 30, 2008 9:39:51 GMT -5
Hydroli,
I see some errors in your last message.
1. A 38mm Weber carb. flows 490 CFM.
2. A stock 5210 Chevette carb. is 26 / 28mm and flows 180 CFM.
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Post by hydroli on Mar 30, 2008 9:57:55 GMT -5
If you want to rev higher than 6500 you may have problems with hydraulic lifters too. I know a member named rpm who makes good solid lifters. I'll send you a PM to give you his email and phone number. For the springs, toymaster has a lot of parts, he may have a set...? You can ask for parts you need in the wanted items section. Be aware that you'll have to machine down spring seats .040 with a "76-"80 head.
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Post by hydroli on Mar 30, 2008 10:20:54 GMT -5
Haaaaa!! I found what's missing!!! Cfm numbers are relative to the vacuum pressure applied during the flow test. As I mentioned, I found the chevette carb cfm numbers in wikipedia (32/36 was the name of the article), below*** is what is said about the chevette carb. wiki.datsun1200.com/index.php/Weber_32/36_Carburetor#Airflow.2C_CFM********* Airflow, CFM 5200 series carbs are mostly fitted with 26mm primary and 27 mm secondary venturis, giving 270 CFM @ 3 inches mercury (note that this is equivalent to a 4-barrel type rating of 193 CFM -- 4-barrel carbs are rated at 1.5 inch mercury). 270 CFM: 26/27 venturis (193 CFM equivalent to 4-bbl style rating) 235 CFM: 23/27 (some, starting in 1978) 245 CFM: 23/29 (1979 up Chevette) ********** As for the weber 38/38 carb, I found many sources but no mention of the mercury inches applied during the test. Maybe 490CFM are numbers at higher presure as my chevette carb numbers were... www.jtoutfitters.com/weber-carburetor-toyota-pickup-truck-4runner-p-4720.htmlAt least, we can say we're both right Thanks for the correction Fields! |
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Post by turbo16 on Jul 13, 2010 19:22:27 GMT -5
here is a link to photos of my fuel injected turbo charged stock with a swirl port head i.e only good for mileage, not for power ( advanced cam) 1.6 I built for a mileage contest. I took 2nd place with 44.2 mpg. I use a haltech ecu and wide band active tuning. s757.photobucket.com/albums/xx217/chevetteturbo/turbo%20chevette/I now have a poted head and am building a stroker with long rods and custom pistons, The stock engine made 146 rwhp. it worked so well i cant wait to see what a good head and cam can do on a engine that has a good rod ratio. I'm shooting for 325 rwhp. I got a lunati cam ground on wider lobe seps.. |
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Post by hydroli on Jul 20, 2010 16:24:32 GMT -5
I really like your setup. How hard was it to tune? Do you already have a cylinder head? I have a #343 never shaved, it would do just right for a forced induction setup. Let me know if you want it.
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Post by turbo16 on Jul 21, 2010 1:52:24 GMT -5
It wasn't that hard to tune at all. The only hard part was the intake fab. The #1 injector had to be placed at an angle under the thermostat housing with single injector of the rail. The 2 3 4 are all on a common rail with the regulator. Iv'e already spent $500 on port work for a '80 NON swirl port head but thanks any way. If you know any one who can build a sheet metal intake with a front mounted throttle body plate I could then make some real horse power. Also if any one knows where the hell I can get valve springs with #210 opened pressure and some solid lifters that would help alot.
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Post by turbo16 on Jul 21, 2010 2:29:21 GMT -5
My budget for this build is $5k .Its already a fuel injected turbo so the hard work is done. If I can get some parts together I can beg Stephen to build it for me. He doesn't live that far away and he knows his gig! Everything hinges on the intake. I won't make over 300 hp with the factory manifold no matter what I do due to distribution problems and cylinder charge difference .I need a sheet metal manifold.
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