gp90se Posted August 20, 2004 Report Share Posted August 20, 2004 I know this is a big topic right now, but Id like to see both sides. The 3.1 makes 20 more horse compaired to a 2.8 n/a. I do understand the 2.8 will rev much higher but torque will be lost, which is just as important as HP off the line. Quote Link to comment Share on other sites More sharing options...
GutlessSupreme Posted August 20, 2004 Report Share Posted August 20, 2004 Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted August 20, 2004 Report Share Posted August 20, 2004 bigger isn't always better....remember what Chevrolet did with the 302ci in the '69 Camaro? i'd love to hear more about this subject also or better yet how about someone throw a 2.8 crank into a 3400? Quote Link to comment Share on other sites More sharing options...
slick Posted August 20, 2004 Report Share Posted August 20, 2004 2.8 crank in 3400- Now that would be nuts. I would bet that the t25/t28 would be better mated to the 2.8 than the 3.1 . Like stated, someone ought to try this out. Quote Link to comment Share on other sites More sharing options...
TurboZ24 Posted August 20, 2004 Report Share Posted August 20, 2004 I have a 3.1 with the regular 3.1 TGP crank in it and I rev upto 8000 (7400-7600 is usually shift point on the track). The 2.8/3.1 isn't going to be limited by the rod/stroke ratio (it's actually quite high on the 3.1 still), but it's more a valve train/head issue. You are going to have to have a cam, lifters, springs, head work, etc that will allow the motor to produce power up high. Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted August 20, 2004 Report Share Posted August 20, 2004 I have a 3.1 with the regular 3.1 TGP crank in it and I rev upto 8000 (7400-7600 is usually shift point on the track). wow!!! Quote Link to comment Share on other sites More sharing options...
gp90se Posted August 20, 2004 Author Report Share Posted August 20, 2004 I have a 3.1 with the regular 3.1 TGP crank in it and I rev upto 8000 (7400-7600 is usually shift point on the track). You are aware TGP gauges can be slightly off If that readings from an aftermarket gauge, im wondering what you are running for springs, rockers, rods and lifters EDIT: seeing you have a TGP motor in a cavi, i hope ya not using the factory tach Quote Link to comment Share on other sites More sharing options...
TurboZ24 Posted August 20, 2004 Report Share Posted August 20, 2004 Actually, I use the factory Cavalier Tach, but also watch the engine rpm on the laptop (aftermarket ECM). The factory tach is off, yeah I know. I do have all autometer gauges if I'd get around to finishing the dash pod to hold them. As for cam, springs, etc I run a crower billet roller, 254/246@.05" .62"/.60" lift 114 separation along with Crane roller mechanical lifters, Crower 440 lb open pressure dual coil 1.455" springs, stainless steel valves, bronze valve guides, on and on, so it's set up for high rpm. Quote Link to comment Share on other sites More sharing options...
TurboGTU Posted August 26, 2004 Report Share Posted August 26, 2004 By the looks of Curtis setup...his engine is trying to outflow the turbo in high rpm. His VE is verry high. Fastest 60d cavi non the less. The 2.8 advantage is in the 9K rpm range and staying there....well with the right hardware. THe 3.1 would beat the 2.8 on a pulling match though. More TQ. You would need a little more gearing on the 2.8 than the 3.1. The 2.8 would produce more HP non the less. Just the physics of mass rotation. THe 2.8 whould be ideal for more speed/hp. The 3.1 give you the punch/quickness. Im trying things out too. Im going to give the 3.1 hell till it goes boom. :devil: Let's see what the stock shortblock can handle...with the help of a GT40 turbo non the less.. I just want to beat the fastes stock block Cyclone/Typhoon....is that too much to ask!.. Quote Link to comment Share on other sites More sharing options...
GP1138 Posted August 26, 2004 Report Share Posted August 26, 2004 How much higher can the 2.8 rev than the 3.1. I've always pushed my 2.8 hard, even when the transmission doesn't want to shift out of first in the mornings... every time it bounces off the rev limiter (which is VERY VERY SELDOM) I think it's gonna blow, but she holds up! Quote Link to comment Share on other sites More sharing options...
1badtgp Posted August 26, 2004 Report Share Posted August 26, 2004 Torque is good, but not always the best. It really depends on what you want. If you want daily driver- stay 3.1. Mine is going for domination. I want a 10 second slip and street cred. I'm destroking to about a 2.7ish(havent done the complete math yet). After doing numerous builds on noth import and domestics, I think this is going to be my best bet.. Also, for whoever is revving that 3.1 to 8k, I would be VERY curious to know what is done. I have a quite a bit done to my build, and only hit 8000 when I have to in order to push my win. It doesnt like it very much. Quote Link to comment Share on other sites More sharing options...
Canada Posted August 26, 2004 Report Share Posted August 26, 2004 Actually, I use the factory Cavalier Tach, but also watch the engine rpm on the laptop (aftermarket ECM). The factory tach is off, yeah I know. I do have all autometer gauges if I'd get around to finishing the dash pod to hold them. As for cam, springs, etc I run a crower billet roller, 254/246@.05" .62"/.60" lift 114 separation along with Crane roller mechanical lifters, Crower 440 lb open pressure dual coil 1.455" springs, stainless steel valves, bronze valve guides, on and on, so it's set up for high rpm. I was about to call BS when I was reading through this thread...............about..........because the stock valvetrain is rated at 6200 rpm. But you don't have a stock valve train. Quote Link to comment Share on other sites More sharing options...
TurboZ24 Posted August 27, 2004 Report Share Posted August 27, 2004 The problem with reving high/high HP with the 3.1 also becomes tranny issues. the HM-125C, 4T60, 4T65 are all rated for a max rpm of 6200 on the input shaft. (I haven't had anyone too tell me why, but I would assume it's a bearing issue and/or pump). As for the HM-282/5TM40, it's rated at 7000 max and it doesn't like to shift past that for sure. Once I replace the headers, crossover, and turbine upgrade (in progress), I want to look into the tranny. I've exploded 1 HM-282 already and I'm sure this replecement isn't going to last all that long. Curtis 91' Turbo Z24 http://www.turboz24.com Quote Link to comment Share on other sites More sharing options...
rudefyet Posted August 27, 2004 Report Share Posted August 27, 2004 i say drop in a 3400 Quote Link to comment Share on other sites More sharing options...
slick Posted August 27, 2004 Report Share Posted August 27, 2004 Curtis 91' Turbo Z24 http://www.turboz24.com Damn, thats your car!!! Hell yeah man. Quote Link to comment Share on other sites More sharing options...
1badtgp Posted August 27, 2004 Report Share Posted August 27, 2004 The problem with reving high/high HP with the 3.1 also becomes tranny issues. the HM-125C, 4T60, 4T65 are all rated for a max rpm of 6200 on the input shaft. (I haven't had anyone too tell me why, but I would assume it's a bearing issue and/or pump). As for the HM-282/5TM40, it's rated at 7000 max and it doesn't like to shift past that for sure. Once I replace the headers, crossover, and turbine upgrade (in progress), I want to look into the tranny. I've exploded 1 HM-282 already and I'm sure this replecement isn't going to last all that long. Curtis 91' Turbo Z24 http://www.turboz24.com That has been an issue for me as well. But I think I have that prob solved. I'm using the auto and I have it holding out pretty well. I have another build gonig back in it after this winter. Oh, and it is a bearing issue. That, and the pump has a hard time holding together. Quote Link to comment Share on other sites More sharing options...
TGPilot Posted August 27, 2004 Report Share Posted August 27, 2004 That has been an issue for me as well. But I think I have that prob solved. I'm using the auto and I have it holding out pretty well. I have another build gonig back in it after this winter. Oh, and it is a bearing issue. That, and the pump has a hard time holding together. I am not an engine builder by any means but I do know basic rules of engine HP/Torque rules. When you go high HP on these 2.6-2.8 V6 motors how are you going to run it in a street application or is this going to be a long straight road course car? HP is one thing...but if you don't have alot of gears to shift to keep your motor in the "sweet spot" on a high RPM/HP motor you will have one hell of a dog on your hands. No torque means no pull unless you have a lot of gears to stay in the extremely narrow power band of a high RPM motor. Using an auto tranny (4T60?) on one of these High HP/High RPM cars would be a funny site at a dragstrip or even a light to light race. You would need to get the car to 60 MPH in 1st gear for it to even feel like it has the power of a Yugo! Then the tranny shifts...loses what? 1000-1500RPM...now you need to wait until you are up to 100+ MPH in 2nd for the power band to catch up and start pulling like a Civic EX. Unless you go with some super exotic torque converter that doesn't lock up till you hit the power band up in the 7000RPM- 8500RPM range, but then how do you over-come the lack of close ratio gearing in an auto tranny? Example...Formula 1 cars. Un-GODLY HP from a relatively small motor (350 bHP per litre and they are 3.0 litre motors) but what amount of torque? They lack considerably in torque compared to HP and it really doesn't matter considering how they slip through the air like a knife, weigh next to nothing, and have 7-speed close ratio transmission. HP is not the end all for performance if you don't have torque or alot of gears to back it up. Another thing is you are talking about building 9000RPM motors...how are you going to overcome the 5250 RPM HP & Torque curve match on a 3000+ Lbs vehicle with little torque? 8) *edit* Just re-read my post and it sounds like I am on the attack...I DO NOT MEAN IT to sound that way...just don't feel like going back and making it sound "sweeter"! Quote Link to comment Share on other sites More sharing options...
TurboGTU Posted August 28, 2004 Report Share Posted August 28, 2004 I know when I remove my toque converter...the oil pump shaft showed sighs of stress on the spines. I didn't see any hot spots on the input shaft or strees on the spines. I did rev the engine to 6500 rpm many times on high boost/load. 7000 two times...ops! The oil pump shaft is a "pencil". I think a chemical hardening or a chromoly unit would be better. SO if im going to stick with the stock drivetrain..then I have to get my VE as high as posible at 6K rpm. I hate that the VE goes high at mid band...then drops like a rock on stock. I think with the mods I have it should at least bump it up more a little higher and at a latter rpm. I know that the fiero guys are advertising a costom made 5 and 6 spd race tranny. Maybe you could resort to that...if your serius and have a Kriptonite Visa card Quote Link to comment Share on other sites More sharing options...
TurboGTU Posted August 28, 2004 Report Share Posted August 28, 2004 Everyone!...Your MAMA! :shock: :shock: :shock: J/K. Jeff...you know who made this. Falconer! 750hp..eat that you Supra fart! (not you max..your ok)[/url] Quote Link to comment Share on other sites More sharing options...
DaveFromColorado Posted August 28, 2004 Report Share Posted August 28, 2004 Hey guys.. time for a little input from someone who doesn't know enough about engines - but knows enough people who do. I was thinking about this, while trying to decide what rods I wanted to use for my Mustang. (2.3 4-banger turbo for those who don't know/remember) I remember learning LONG LONG ago that the longer the rod, the ability to create torque is increased. If you use a shorter stroke crank, and a LONG rod, you'll be able to make ton's of torque, but little horsepower due to the displacement, unless you are turning TON's of rpm's - which means you'd need to upgrade the valvetrain, because as someone else pointed out, that's the weakspot on these motors. Even the DOHC engines have that problem. Personally, if I were to run a turbocharged 3.1 - I'd use the longest rod available (custom?) and a set of custom pistons to move the wrist pin height so they don't end up commin' out of the bores. Using the longer rods will decrease the rod angles at the 90* and 270* points per cylinder, it will also increase piston dwell time, and allow for slower piston speeds when comming to TDC and BDC meaning the piston, bearings, and rods won't undergo all the extra stress of a short rod/short throw setup. but that's just my .02 there for ya. --DaveFromColorado. Quote Link to comment Share on other sites More sharing options...
FastSE2DR Posted August 28, 2004 Report Share Posted August 28, 2004 Everyone!...Your MAMA! :shock: :shock: :shock: J/K. Jeff...you know who made this. Falconer! 750hp..eat that you Supra fart! (not you max..your ok)[/url] thats 750hp? that looks like more than 750hp worth there...a supra friend of mine makes only like 600whp and he runs 9s with a TH350 tranny and hes goin with a powerglide its crazy...all these supras make 1000+hp but cant do anythin with it..he makes 600 and runs 9s Quote Link to comment Share on other sites More sharing options...
1badtgp Posted August 28, 2004 Report Share Posted August 28, 2004 That has been an issue for me as well. But I think I have that prob solved. I'm using the auto and I have it holding out pretty well. I have another build gonig back in it after this winter. Oh, and it is a bearing issue. That, and the pump has a hard time holding together. I am not an engine builder by any means but I do know basic rules of engine HP/Torque rules. When you go high HP on these 2.6-2.8 V6 motors how are you going to run it in a street application or is this going to be a long straight road course car? HP is one thing...but if you don't have alot of gears to shift to keep your motor in the "sweet spot" on a high RPM/HP motor you will have one hell of a dog on your hands. No torque means no pull unless you have a lot of gears to stay in the extremely narrow power band of a high RPM motor. Using an auto tranny (4T60?) on one of these High HP/High RPM cars would be a funny site at a dragstrip or even a light to light race. You would need to get the car to 60 MPH in 1st gear for it to even feel like it has the power of a Yugo! Then the tranny shifts...loses what? 1000-1500RPM...now you need to wait until you are up to 100+ MPH in 2nd for the power band to catch up and start pulling like a Civic EX. Unless you go with some super exotic torque converter that doesn't lock up till you hit the power band up in the 7000RPM- 8500RPM range, but then how do you over-come the lack of close ratio gearing in an auto tranny? Example...Formula 1 cars. Un-GODLY HP from a relatively small motor (350 bHP per litre and they are 3.0 litre motors) but what amount of torque? They lack considerably in torque compared to HP and it really doesn't matter considering how they slip through the air like a knife, weigh next to nothing, and have 7-speed close ratio transmission. HP is not the end all for performance if you don't have torque or alot of gears to back it up. Another thing is you are talking about building 9000RPM motors...how are you going to overcome the 5250 RPM HP & Torque curve match on a 3000+ Lbs vehicle with little torque? 8) *edit* Just re-read my post and it sounds like I am on the attack...I DO NOT MEAN IT to sound that way...just don't feel like going back and making it sound "sweeter"! This is a good theory, but F1 cars are on the extreme. Think about it, I've built 2.0 4g63 engines that runs 10's with a slushbox, and forward Motion built a 9 second neon that could run on the streets well, and used an auto trans. It's in the final drive ratio. Also, it will still have a good amount of torque. I'm thinking around 7-800 whp, and 650-780kb/ft of torque. It will lag a bit of the line, but what better way to catch tracion? Torque can actually hinder you after a certain point, and with this much torque on tap I doubt it will be much of a dog. I should reach max torque by 4500rpm or so, compared to stock, I believe, is 3600rpm. Quote Link to comment Share on other sites More sharing options...
TGPilot Posted August 29, 2004 Report Share Posted August 29, 2004 I am truly curious to see what you guys get for "Real" #'s when the motors are built. On paper it sounds like a point and shoot car for sure!! Quote Link to comment Share on other sites More sharing options...
TurboGTU Posted August 29, 2004 Report Share Posted August 29, 2004 My memory is a little cloudy..but I think that engine is 2.6...or was it 2.5???. Jeff knows. Look at the "one off" manafold...those runner have Tq written all over them. THey help to spool up the turbo. Short box hand fabed intakes lack this lowend tq. Dave Im sure your fimiliar with Essilinger. They also recomend long rods. My brothers 2.3 was going to get some..but decited to hold off till he got the aluminum "stock" Turbo head from them. Pre 67 SBC small mains rods can fit our 60degree engine...so long aftermaket rods can be machened to fit along with new custom forged pistons. I was even thinking of going extream with aluminum billet rods. One opinion though..I think H beams are crap...seen too many fail. I beams all the way. Ain't that the truth TGPilot...It's all sounds nice on paper oh..I mean on screen..LOL>..but its all about the real world..and the engeneers (thats you and I) ability to do his homework. Got deep pokets! One question....What are Potter heads? The ones on this engine are 2nd gen... :shock: Quote Link to comment Share on other sites More sharing options...
DaveFromColorado Posted August 29, 2004 Report Share Posted August 29, 2004 when workin' on the ford 2.3 engine, do NOT use the stock Chevy rods, they won't even hold up in an N/A motor. I wanted the esslinger alum. head for my 'stang, but I stuck with my old round-port iron head. I will be going with the Crower I-beam rods, and a set of CP pistons, total seal rings gapless top ring. If I had the money, I'd get the stroker crank, tall-block and go for the all out 3-litre. Anyhow as for adding power to the 3.1, rather then de-stroking it I'd imagine the long rod idea would work on the 660's as well as it does on the 2.3, the mechanics of rod angle's is the same no matter what engine it's in, now all you have to do is solve the RPM cap with the valvetrain... --DaveFromColorado. Quote Link to comment Share on other sites More sharing options...
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