Major weakness in the 4G63 motor...

[pneumo]

Here's some; first is a 2G with the T25 plus some mods from our own Larryd www.newcelica.org/larryd/dyno/02-01-02-dyno_comparson.jpg
Next, this is a good example of a proper A/F ratio, although the power is a little more than stock. www.twingles.com/ideck/datalog/dyno092101a.jpg
This is a great comparison between stock cams and Web cams on a 1G with small 16G turbo, plus a lot of mods www.roadraceengineering.com/eclipsetech/dynocharts/mikedyno-webcams.jpg

 

[larryd]

I do not understand the point of this thread. There is nothing wrong with the 4G63 engine that will cause the car to not be fast up top. Ofcourse in stock condition the car isnt exactly a top speed runner. it wasnt designed to be, but properly modded the car will run down many cars on the highway.

Simple point here is if you want to go faster and have more top end power then add more mods. Cams and a sheetmetal intake manifold would make a large difference up top if and only if you are running a nice size turbo first.

 

[na90dsm]

good point.

my question still stands. which cam is bigger the n/t 90 or the turbo 91 cam.

 

[Phoenyx]

Originally posted by pneumo
Here's some; first is a 2G with the T25 plus some mods from our own Larryd www.newcelica.org/larryd/dyno/02-01-02-dyno_comparson.jpg
Next, this is a good example of a proper A/F ratio, although the power is a little more than stock. www.twingles.com/ideck/datalog/dyno092101a.jpg
This is a great comparison between stock cams and Web cams on a 1G with small 16G turbo, plus a lot of mods www.roadraceengineering.com/eclipsetech/dynocharts/mikedyno-webcams.jpg

Ok. The first link doesn't work. The second link, this car is all over the place with his curve. I don't know what's wrong with his car (maybe ignition break-up?) The third link shows that a cam gives better topend power.. but guess what? Even with the Web cam the car still starts to drop in power...


-M

 

[Phoenyx]

Originally posted by larryd
I do not understand the point of this thread. There is nothing wrong with the 4G63 engine that will cause the car to not be fast up top. Ofcourse in stock condition the car isnt exactly a top speed runner. it wasnt designed to be, but properly modded the car will run down many cars on the highway.

Simple point here is if you want to go faster and have more top end power then add more mods. Cams and a sheetmetal intake manifold would make a large difference up top if and only if you are running a nice size turbo first.

I agree. But the point of this thread is to see why with few mods, the car still isn't strong on the top side. Why do we have to drastically change the behavior of the car to get better topend? That's the question basically.

-M

 

[na90dsm]

very good point. it seems to drop off at about 6500rpm.

 

[Phoenyx]

Here's is my RX7 when it was barely tuned with the Haltech EMS and a T04E turbo:

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Notice how it never stops making power...

-M

 

[na90dsm]

wouldnt that be a little different because of the haltek and not having the stock ecu.

 

[Phoenyx]

Originally posted by na90dsm
wouldnt that be a little different because of the haltek and not haing the stock ecu.

No. Tuning is tuning.. regardless of the ECU. If you have the capability to alter the signal, then..

The car is a different animal, but it is an example of a good topend performer. Hopefully when I get the L2R, I'll see a dyno sheet like this with the Talon..

-M

 

[na90dsm]

agree'd

 

[larryd]

Originally posted by Phoenyx


I agree. But the point of this thread is to see why with few mods, the car still isn't strong on the top side. Why do we have to drastically change the behavior of the car to get better topend? That's the question basically.

-M

because the stock turbos suck and you have restrictions in the stock cams and intake manifold.. What more info do you need?

Remember another thing, this car isnt like a Honda. It does not make peak hp at the end of its RPM range. Its a different type of power curve but still very impressive none the less. I have seen dynos on the other hand though where a DSM has made its peak hp at the top of the rpm range and that was with a GT series turbo and cams.

 

[pneumo]

somehow I can't edit the first link, take 2 www.newcelica.org/larryd/dyno/02-01-02-dyno_comparison.jpg

 

[Phoenyx]

Originally posted by pneumo
somehow I can't edit the first link, take 2 www.newcelica.org/larryd/dyno/02-01-02-dyno_comparison.jpg

This dyno proves my point! At every run, the car loses HP after 6000rpms!

-M

 

[larryd]

As once again I said I was on stock cams with stock intake manifold and a T25. With the L2R, HKS cams, and a Sheet Metal intake manifold the car would make more and more power all the way to redline. Every car I know of makes its peak hp less at a spot lower then the top of the RPM band unless its got a VTEC or VVTLi type engine.

 

[Phoenyx]

Originally posted by larryd
As once again I said I was on stock cams with stock intake manifold and a T25. With the L2R, HKS cams, and a Sheet Metal intake manifold the car would make more and more power all the way to redline. Every car I know of makes its peak hp less at a spot lower then the top of the RPM band unless its got a VTEC or VVTLi type engine.

LarryD,

Not arguing that at all.. I agree 100%. So adding cams and a bigger turbo seems to be the ONLY route to increasing the topend power. And this is because of the OEM restrictions to the car (i.e. manifold, cams, turbo) which people have admitted.

Ok, I am satisfied with the responses.

Thanks fellas!!

-M

 

[pneumo]

why would you want the power to keep going up until the end of the rpm band like the RX7? to get there you'd have to sacrafice too much lowend power. I've seen cars with powerbands so peaked that they fall out of the power when they shift from 4th to 5th. wouldn't you rather have this? shepracing.com/pictures/dynochart.jpg

 

[larryd]

Personally Id love to have the car make good power in the low end like it does right now and be able to pull hard all the way to redline making peak hp at redline but thats pretty hard to do. Most of the larger turbos that you run will move your powerband to a higher # which sacrifice low end.

I know when I had my Celica I loved knowing it made peak hp @ 8200 right at fuel cut. It was fun to rev it out

 

[na90dsm]

heres a example. this is a twin turbo dodge vipe with the stryker upgrade. it got the SVSi TT Stage III upgrade. even with the extensive mods to this car it makes 1100hp at the crank and 1300 tq at the crank. this dyno sheet shows the cyurve on this car and it even falls off at a certain rpm. the dyno sheet is at the bottom of the page

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http://www.supervipersystems.com/Up...er_TT_Stage_III/svs_stryker_tt_stage_iii.html

 

[na90dsm]

Originally posted by pneumo
why would you want the power to keep going up until the end of the rpm band like the RX7? to get there you'd have to sacrafice too much lowend power. I've seen cars with powerbands so peaked that they fall out of the power when they shift from 4th to 5th. wouldn't you rather have this? shepracing.com/pictures/dynochart.jpg

i dont think i would like my car to make power all the way or past redline. i think with the power dropping off slightly a little bit before redline you know that your using all the power from the engine at its strongest point. for example if your car made ower all the way to 8k, an you shift at say 7500k you still have some power left over that you could tap into. granted if you had tat kindapower in that range of rpm you would know about it and shift at that point but that was just an example.

 

[Phoenyx]

Originally posted by pneumo
why would you want the power to keep going up until the end of the rpm band like the RX7? to get there you'd have to sacrafice too much lowend power. I've seen cars with powerbands so peaked that they fall out of the power when they shift from 4th to 5th. wouldn't you rather have this? shepracing.com/pictures/dynochart.jpg

That dyno sheet is way out of normal specs for the average consumer. I would love to have it! However, he did use 125shot of Nitrous.

I love my powerband in the RX7. Why? With the low torque, the car didn't spin much on take off, but it would surely catch you! I've had plenty of Camaro LS1s leave me by a car or so only to get caught because the RX7 kept pulling and pulling...


-M

 

[sential]

Originally posted by Phoenyx


Ok. The first link doesn't work. The second link, this car is all over the place with his curve. I don't know what's wrong with his car (maybe ignition break-up?) The third link shows that a cam gives better topend power.. but guess what? Even with the Web cam the car still starts to drop in power...


-M

okay first of all, there's nothing wrong with the 4g63. Its got major low end grunt so when you want power its there. I think thats awesome cause even with the big turbos you not feeling a whole lot of lag like you would with a honda or something with low torque numbers. Its just a different power band.

and exactly like you said, you went from a 12 second rx7 to a 14, maybe 15 second talon. That's why you feel like its slow. Rotary engines are known to be screamers that pull way up in the RPMS. I not really familiar with them but I swear I've heard of rx7's pulling way into and even past the 9,000 rpm range. They rev like a freakin motorcyle.

Then you talk about the car starting to drop in power @ 6500 with the web cams, but did you notice there was almost a 50 hp increase just by adding some cams. If that's not responding to mods then I don't know what is. The 4g63 is a beast, you just got to know how to work with it.

peace out

 

[NosLaser]

There is nothing short of beating my head against a wall that will make the pain from reading this thread any less severe. Perhaps I should go gnaw off my own leg in an attempt to distract myself from the massive headache that has insued from trying to understand your logic. Phenyx, dude, you need a reality check, and to re-school yourself on turbo cars, how they work, and how they make power. You were more in line with the Probe GT argument, but now you pull a ROTARY with a TO4E turbo on it against a low compression 2 liter 4 cylinder with a 14B on it. You need to understand something first and foremost. While cams, intake manifolds, cylinder heads, etc. HELP make power on a turbo car, the majority of the power, and where it occurs in the powerband is going to be made by the TURBO. You can take Sean Glazers car which runs 8's at over 160MPH and has a bad ass built motor, custom intake manifold, all sorts of head porting R&D, etc. and slap a T25 on it and it's going to fall off power above 5500rpm REGARDLESS of the motor the car has. You could take a stock 2G, and for arguments sake slap on a 60-1 and it's going to continue to make power after 6K rpm. These are all characteristics of the turbocharger being used in each particular application. It's not a limitation of the motor (for the 3rd rime) and you admitted already that your vehicle has issues (for the 3rd time) so you really just need to comprehend this information before you dig yourself deeper, and pull out an even more RIDICULOUS comparison than the RX-7!!

Regards,

 

[GreenGSX]

Phoenyx

Take 20 minutes with a datalogger and tune your car. Its knocking and your not listening. Your being thick headed about losing top-end power when you don't know what your talking about. I've had multiple DSM's and they all suck when there not tuned and they all fly when they are. Post again when your sure the car is running perfectly and you still think it has no top end. Then we can take you seriously and talk about things like gearing and IC pipe sizing etc...

Tim

 

[InferiorWang]

about the cams and people wanting my info verified, there was a big discussion on dsmtalk a while ago (forgive me, dsmtuners kept going down) and the general concensus was the the 90 turbo exhaust cams suck and that upgrading to a 91-94 turbo exhaust cam helped that car breathe a lot better. If someone felt like going and finding that for us it would be great, but I have to get to class.

 

[autronicDSM]

This thread is so pointless, obviously guy has no clue what makes top end power and i doubt he has a 12sec RX7 or whatever when yestarday he was asking how upgraded fuel pump gives more fuel...

Somebody should lock the thread.