MarkAngelo05 said:

Hi!

I just bought a 1995 Eclipse GST with a 6 bolt swap, TRE RACE TRANS, etc. The compression checked out, and it is a stock 6 bolt motor. The motor runs very smoothly and sounds very quiet, even though it's got stock 1G lifters.. He's only ran mobil 1 synthetic oil in it.

Previous owner seems to be trusworty, and showed me that he put on a new waterpump, timing belt, removed balance shafts, and the compression was healthy. Which is why he swapped it in the first place.

Should I do a rebuild before swapping it into my 97 GST? or should I just swap it over.

I know that I am taking the head off to put in a cometic head gasket and ARP head studs.

I'm not looking to go over 400whp. I'll be very happy to make over 300whp SAFELY. I'll be boosting around 20-22 psi with an 18G variant turbo with a 15 degree clipped TD05 wheel. Using Extreme turbo system's 10 inch tall 3 inch thick Race intercooler.

I'll also be installing BC 272's when we do all this.

To beable to rev to 8k rpms, will BC springs and retainers be good enough? or I do not need anything else, like rods/piston combo?

Currently tuning with DSMCHIPS/Jeff's help and AFC. with a wideband a/f system.
Looking towards dsmlink.

Thanks!

Mark Padilla

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Do a compression test. Let that determine your path.

How serious do you plan on making your car? If it will be a sub 400hp engine, you should be okay with stock internals. If you want to make it a firebreather, it'd be much easier to tear into with the engine on a stand. Also, if you're pulling the head, you'll have the timing belt off, so cams might not be a bad idea if you want a revver. Hope this helps, good luck to you.

JayRolla said:

I would not fix it untill it needs it. The 6 bolts can take a lot of abuse. When I went to the dyno the tuner was like these cars have great motors. Cant even blow them up with a hand grenade.

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THanks for all the info...

So does this mean the stock valve train and stock bottom end can withstand revs to 8k rpms? at 20-21 psi of boost and 272 cams...?


I will also be doing a compression test MYSELF on the car very soon here.

I'm also not planning on wanting to go over 400hp. I'll be very happy to have a reliable 300+ whp daily driven car. ..

my current stock motor with arp head studs, rebuilt head , stock head gasket is boosted 19-20 psi daily and made 260whp.. My compression is 130 on all 4, which is below specs on a stock 7 bolt, I think. It also went up to about 150 when I put a capful of oil...

Thanks! please keep the information coming!

Mark

MarkAngelo05 said:

So does this mean the stock valve train and stock bottom end can withstand revs to 8k rpms? at 20-21 psi of boost and 272 cams...?

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NO!!!!!

If you rev your engine that high with 272 cams, you will experience what is called valve float. Valve float happens when the rate of the piston coming up moves faster then the springs for the valves can push them fully closed. This problem only worsens when you uses cams with higher lift. Worse case senerio you bend some valves

If you want the engine to rev higher, upgrade the valvetrain. The simpliest and most cost efficent way to do that is valve springs with a higher spring rate. You can either get upgraded single coil valve springs or dual coil valve springs. Single coil springs can cost any where from $100-$300 for a set. Dual coil springs usually start at $300 and can be as costly in excess of $500. Other tadbits you can use is replacing the rockers, retainers, or keepers.

Other things to keep in mind is the usuability of RPMS in that range. As you start to get higher in the RPM band the air can not get into the cylinders at the rate the valves are opening and closing, the engine sort of runs of breathe and you will feel a noticable reduction in power, this is the redline of the engine. The most effective way to remedy this problem is to install larger cams (which you have). Also you could upgrade the valves themselves and port the head to make it easier for the air to enter the cylinders.

My personal suggestion, don't rev to 8k RPMs. If you feel it's a "must need" goal. Pick up some JAM or KKS dual coil valve spring set and Ferrea Super Allow or Hollow Valves 1mm oversized. Get a 3-angel valve job done to the head. Port the intake and exhust runners. replace the valve guides and seals. Install the cams you already have and slap it all together.

For extra measure replace the rockers with new OEM units.

Okay, well forget revving to 8k then.. I'll just keep it around 7k to 7.2k rpms like I usually do. So stock bottom end, ICS titan headgasket and arp head studs with 272 cams should be strong enough of a powerplant.

Thanks!

Mark

The bottom end does not hold the cams, push rod motors, however, do.

With ARP head studs and an upgraded head gasket, you should be able to sustain 400 whp easily. There has been a debate wether or not the stock bottom end could hold over 500 whp, I've seen it, but I also seen a motor with 450whp lose its guts. If your goal is 300 FWD hp, you will have no problem. I would upgrade the turbo to a E316G and get some cheap upgraded valve springs and call it a day, you will likely exceed 300 whp.

By the way, since you're out in Hawaii, look up a guy named Tony. He drives a modded black EVO 9, he used to have a 96 GST while he was living here. Smart guy, very cool.

laserspeeddemon said:

The bottom end does not hold the cams, push rod motors, however, do.

With ARP head studs and an upgraded head gasket, you should be able to sustain 400 whp easily. There has been a debate wether or not the stock bottom end could hold over 500 whp, I've seen it, but I also seen a motor with 450whp lose its guts. If your goal is 300 FWD hp, you will have no problem. I would upgrade the turbo to a E316G and get some cheap upgraded valve springs and call it a day, you will likely exceed 300 whp.

By the way, since you're out in Hawaii, look up a guy named Tony. He drives a modded black EVO 9, he used to have a 96 GST while he was living here. Smart guy, very cool.

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Hey.. I just ordered my ARP head studs and ICS TITAN Copper headgasket(It's supposedly good for over 30 psi of boost with ARP head studs. I'm going to just swap the 6 bolt motor right over.

I believe my turbo flows more than an Evo316G. I've got an 18G wheel stuffed into a PORTED EVO 3 GT casing with a 15 degree clipped td05 turbine wheel.

Did tony's evo9 come black, or was it red before? if so, then I know of him.

Thanks for the oppinions, please keep them coming.


Mark

Ah, your profile did not note an already upgraded turbo so I assumed you are running the factory T-25. I would stick with the turbo you have I know ARP is good, have not tried the TITAN. Being that is a copper HG, it should be fine. Make sure you torque the head studs in the proper order and to proper specs.

Tony's EVO was always black, I saw it the first day he got it from the factory.

**edit** I just noticed it did, maybe I looked at the wrong profile?

Revving to 8 grand with 272s is not going to cause valve float on stock valvetrain. If you bought the BC spring/retainer set you should be good to over 9 grand. People have been revving to 8500 with HKS 272s and stock valvetrain for at least 6-7 years now with no problem.

Now, whether you actually need to rev to 8000 is questionable on anything smaller than a 20g/50 trim. Probably not.

Okay, let me first say that I have done the research on all 4 or 5 of the threads involving revving the stock valvetrain to 8k on 272 cams. I understand that the head can effectively do this, and then more, with no upgrades and maybe just a little bit of double-checking to ensure everything is good to go. I am also not trying to create a sort of bench-racing thread....

So, my questions is....

For people with increased rev limits (8k), upgraded cams (BC 272's), larger turbos (Slowboy Racing G60), and sheet metal intake manifolds (JMFab Race), or similar... when did you notice that power would drop off in the RPM band? I know the stock setup isn't good too much beyond 6500. However, I was wondering with my cams, turbo, and intake manifold if I would be able to take my car efficiently, and efffectively, into the 7800-8000 rpm range and still be producing power.

Or would I be wasting my time? Anyone have experience with this or a bit of input? I'm not looking to make any crazy numbers (which is why I don't really want to dyno tune), but more idealy shoot for mid-to-low 11 second time slips on a fun, ballsy street tune with DSMlink.

All my mods are in my profile. Any input of personal experience is appreciated. Thanks in advance,

-Matt

here is my setup for some background..


-9:1 compression evo 3 engine
-SBR G50 @ 26 psi
-JMF SMIM
-Snow Performance Methanol injection kit
-FP2 cams revving stock valvetrain to 8k
-300M COP
-DNP manifold
-Punishment racing 02 housing
etc etc


I don't have any issues with making power to 8000 RPM. It doesn't drop off like stock cams do. The car is pulling so hard/wheel spin (especially 1-2 gears) that its almost impossible to tell even in the higher gears when the power drops off below 8k. I usually shift 7700-7900 RPM depending on gear...Seems to be just fine, pulls hard. I suspect that over 8k on my current setup (don't know just guessing here) that I think it would start to drop off. however everything is all relevent to you tune/cam timing/engine setup etc. Best way honestly to know is to get the car dyno'd.

I suspect you will be revving as close to 8k in the lower gears as possible as you do have a fairly laggy turbo (wife runs that turbo) to help spool in the lower gears on the next gearchange.

Thanks for the reply. Appreciate it. Are you still using an OEM style belt, or did you upgrade to something a little more sturdy to handle the stress of high-revs?

I was revving to 8500 on stock motor with hks 272's, scm 61, dsmlink, magus, stock timing belt last year.... Worked just fine just make sure your springs are still within spec...

But if it was me and your going to go thru the process of testing the springs just replace them with bc s/r.... They are pretty cheap...

I ran to 8500 all the time in 2007 (fp2's, SMIM, 50trim). This year I still only rev to 8500 (280's, SMIM, BC valvetrain, 50trim). The difference between 2007 and 2008 is that I'm doing it safely. Take that for what it's worth. I know a handful of people, including myself, that have gone that high on the stock valvetrain with no problems, but you need to assume the risk of valve float and other consequences if you do so.

That being said, DSMLink logs show that airflow does NOT wane down after it crosses 7k. I continue to make the power up until I shift with airflow plateauing a bit before 8k.

Sounds awesome. Now, I'm certain I will have no issues revving that high... how does that translate into track speed? Again, not wanting to bench race, but it would be beneficial to do when you can because you can run the longer, more powerful gears longer, right?

ie Instead of shitting at 7k in 1st gear at ~30mph, you can shift in 1st gear at 8,000rpm and be going x amount of speed. How much faster/higher does that allow you to go in that gear?

I spent like $200 on springs and retainers and installed them in about 2 hours and f'ed around alittle while doing it (didn't pull the head or either manifolds or anything). Now I only have a 4g61 with fp2's and a fhr intake manifold, but it pulls hard to 9000rpm. the car is way more fun and I don't shift as much.

mach4g63t said:

Sounds awesome. Now, I'm certain I will have no issues revving that high... how does that translate into track speed? Again, not wanting to bench race, but it would be beneficial to do when you can because you can run the longer, more powerful gears longer, right?

ie Instead of shitting at 7k in 1st gear at ~30mph, you can shift in 1st gear at 8,000rpm and be going x amount of speed. How much faster/higher does that allow you to go in that gear?

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Airflow is pretty relative to horsepower. With horspower, you want to straddle the peak or the hp curve when shifting; the ideal shiftpoint would land right at the same hp as you left off in the previous gear.

Without getting too technical, you can simply look at airflow via dsmlink and see if you're shifting at the optimal rpm. If the airflow in the beginning rpm of the next gear is considerably lower than the airflow in the previous gear at x rpm(shiftpoint), you should have shifted at a higher rpm/later. If the airflow is considerably higher in the next gear than the end of the last, you should have shifted at a lower rpm/sooner. This x rpm will be different between the 1-2 shift, 2-3, 3-4 etc since the gear ratios are spaced closer between higher gears and subsequently have less of an rpm gap between gears. Airflow WILL eventually drop off if you rev the engine far enough, but you have to think about where it places you in the next gear. This will make you want to shift at a higher rpm in 1st gear and at a slightly lower rpm for each following gear. Example, 7500 in first, 7200 in second, 7000 in third, 6900 in 4th.

In Tom's case, he isn't revving the engine far enough for the airflow to drop back off, instead it just plateaus. In this case, you would shift at redline each and every gear to make the most out of the power available.

I disagree a bit. there is alot more going on than worrying just about airflow. For instance power to the ground is what you should consider. gearing. Gearing is a torque multiplier. So comparing 1-2-3-4 there is a huge difference in gearing (multiplier) in the lower gears and less of a difference than say comparing higher gear Thats something you will not see in airflow numbers. Generally 1-2 gears in most cars usually you rev higher because at say XXXX RPM in first gear (with the multiplier with gearing) will be more power to the ground than XXXX RPM with a less of a multiplier at that same point in second gear (if you were to shift). Its a very fine line when considering reving beyond the power band (peak Airflow numbers) is an advantage when considering gearing. Obviously there comes a point when airflow just drops off so significantly that the gearing is no longer an advantage over the next gear. This is generally why 1-2 gears are usually a higher shift point. The taller 3-4 gears are usually closer in gearing and generally rule of thumb is to shift to have the RPM band land at peak torque...atleast in theory. There are so many things going on in a drag race and so many variables. I agree for the fact that airflow gives you a good base to use for peak torque/HP and shift points, however it doesn't really reflect what is happening at the wheels on the track. Just my thoughts anyways.

I understand what both of you are saying, and it makes sense. What I'm really trying to understand is how much faster (mph) will it make your car by running the gear out? Is there more of a gain in higher gears than the lower gears, or is it generally the same just the power is a less in the higher gears?

haioku-rocket said:

I disagree a bit. there is alot more going on than worrying just about airflow. For instance power to the ground is what you should consider. gearing. Gearing is a torque multiplier. So comparing 1-2-3-4 there is a huge difference in gearing (multiplier) in the lower gears and less of a difference than say comparing higher gear Thats something you will not see in airflow numbers. Generally 1-2 gears in most cars usually you rev higher because at say XXXX RPM in first gear (with the multiplier with gearing) will be more power to the ground than XXXX RPM with a less of a multiplier at that same point in second gear (if you were to shift). Its a very fine line when considering reving beyond the power band (peak Airflow numbers) is an advantage when considering gearing. Obviously there comes a point when airflow just drops off so significantly that the gearing is no longer an advantage over the next gear. This is generally why 1-2 gears are usually a higher shift point. The taller 3-4 gears are usually closer in gearing and generally rule of thumb is to shift to have the RPM band land at peak torque...atleast in theory. There are so many things going on in a drag race and so many variables. I agree for the fact that airflow gives you a good base to use for peak torque/HP and shift points, however it doesn't really reflect what is happening at the wheels on the track. Just my thoughts anyways.

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Airflow is loosely HP, I was just using that as an example since it is readily available through dsmlink. Horsepower is torque at the wheels through gearing, and torque at the wheels directly correlates to acceleration. Where torque is acceleration in a given gear, HP is acceleration at a given speed, through gearing.

It's really as simple as staying on top of the HP curve, and gearing will dictate what rpm you need to shift at to do that. We are really saying the same thing You can take your HP graph and compare it with your gear ratios and find the perfect rpm to shift at for each gear. Those are really the only two variables as long as you don't have to worry about traction; it's a pretty exact science.

mach4g63t said:

I understand what both of you are saying, and it makes sense. What I'm really trying to understand is how much faster (mph) will it make your car by running the gear out? Is there more of a gain in higher gears than the lower gears, or is it generally the same just the power is a less in the higher gears?

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It will all depend on how broad your powerband is. I would say more of a gain in lower gears simply because the higher gears are spaced closer together. You have the same power to play with in higher gears, just less mechanical advantage/leverage through gearing.

Its nice shifting at 8500rpms.. but which tranny and clutch can do that??
With my old setup SBR 3500 and stock tranny.. wasn´t able shift higher than 7K.. when turn 7250rpms..tranny didnt shift next gear.. and my clutch burned..

Don´t tell me go with Dog box..
Which trannies you using??
Thanks
Venca

Hi Venca,
I had good results with a sprung 6 puck clutch, it handled 8k+ shifts. A sprung 4 puck would shift even better, but it would sacrifice streetability.

A good DSM trans should handle 8k shifts. The double syncro second gear is a must. The EVO3 trans had double syncro 2nd, 3rd, and 4th gear, as well as close ratios.
Check out www.jackstransmissions.com

hey,
Yes,Thats what I was looking for
Jacks assembled Evo gears..
and ACT 6 puck sprung disc
Venca

pneumo said:

Hi Venca,
I had good results with a sprung 6 puck clutch, it handled 8k+ shifts. A sprung 4 puck would shift even better, but it would sacrifice streetability.

A good DSM trans should handle 8k shifts. The double syncro second gear is a must. The EVO3 trans had double syncro 2nd, 3rd, and 4th gear, as well as close ratios.
Check out www.jackstransmissions.com

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My trans has always shifted rather well, and I bolted in the Fidanza 3.2 kit with the 4-puck. Hopefully this should be everything I need. Might go with some Redline trans fluid just to make sure everything is nice and happy. Sounds good though. Thanks to everyone who chimed in.

Mr Peepers said:

Airflow is loosely HP, I was just using that as an example since it is readily available through dsmlink Horsepower is torque at the wheels through gearing. Where torque is acceleration in a given gear, HP is acceleration at a given speed, through gearing.

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sorry still disagree. Horsepower is a function of torque. nothing more. Gearing will change torque values as it does HP values. I guess you could say gearing is a torque/HP multiplier... As gearing affects both. Could go into it exactly but it seems like you are a smart guy and understand how HP is calculated.

Mr Peepers said:

It's really as simple as staying on top of the HP curve, and gearing will dictate what rpm you need to shift at to do that. We are really saying the same thing You can take your HP graph and compare it with your gear ratios and find the perfect rpm to shift at for each gear. Those are really the only two variables as long as you don't have to worry about traction; it's a pretty exact science.

Click to expand...

I more or less agree with that.