[Cramec]

I just got my turbo elise dyno'ed. It made 250 at 11 lbs. How much power or boost can stock motor take.

 

[Almighty]

The snarky answer would be 250hp at 11psi of boost.

The real answer would be, it's all dependent on the set up. Could you phrase the question a little better?

 

[tommyc]

What turbo system? What turbo? That is good power for a stock lump. As mentioned it will depend on fueling and cooling but probably not much more on a stock motor.

 

[doug_porsche]

I am going to answer a question that was not asked.

At 250 RWH, the stock trans, particularly 3 gear from what I have read, will not take much more. (Repeating what I have read, not what I know)

Figuring 10% loss, and I dont know what our drive train loss is, that is putting you in the 275ish range. From what I have read is 300HP is the $$ number for the trans.

 

[Giantmcm]

I have to disagree with Doug. When it comes to the transmission, sure if you drop the clutch at 11 psi you definitely run a very strong risk of popping a transmission. But I have heard of many (including Fred) who is pushing 350 hp at the fly on the stock 6 spd trans, and this being on the REV400 kit which is 10+ psi instantly as it is a supercharger kit. Also this is a car he auto crosses in the SSM class.

And from my understanding, with a turbo generally it all deals with your tuning system...but I am far from an expert, and just adding my 2 cents as I am doing a turbo system in my elise hopefully by next winter. Saving up for my tuning software and a tune.

 

[Sergeant]

Not meaning to hijack the thread but to add to his question: should you always upgrade your clutch when adding a supercharger?

 

[tommyc]

My stock clutch with vf works but will slip on a hard launch. 1st run on drag strip was ok with a 1.9 60'. When I tried to do better 2nd gear slipped as well as third. On the road course it was fine as well as street. I will upgrade but am procrastinating because of the work! But yes it is a good idea to do. The act hdss with fidanza flywheel is my purchase


Sent from AutoGuide.com App

 

[oldmansan]

I would also disagree with Doug based on experience. I'm making 281 to the wheels on the stock clutch and transmission. I haven't had any issues.

San

 

[Cramec]

I have Gt35rs turbo, raduim air to air innercooler, custom piping to innercooler. Upgraded clutch, new fuel pump, larger injectors. Alot more to list but not needed for my question. I feel I should make more with those add-ons. Just don't want to buy motor just yet. 12k on the clock now.

 

[doug_porsche]

Well, I just added a SC to the car, so I hope you are right about the trans, but I think I will still avoid the local drag strip.

 

[oldmansan]

I feel I should make more with those add-ons.

I would agree.

San

 

[bri3d]

I have Gt35rs turbo, raduim air to air innercooler, custom piping to innercooler. Upgraded clutch, new fuel pump, larger injectors. Alot more to list but not needed for my question. I feel I should make more with those add-ons. Just don't want to buy motor just yet. 12k on the clock now.

I think that at 11psi you're pushing about the top range of what people run on the stock internals, but it sounds like your car should be putting down a few more horsepower.

Keep in mind that dynos are different, sometimes by 10+% so 250 on your dyno might be 270 on someone else's, and 270 seems about right for 11psi.

I've found people on here saying they were making 275 or so with 11psi on stock internals with pump gas, and I think the Radium people got a GT2860RS @ 11psi on a stock engine to 300hp or so on race gas.

Lots more variables than just absolute maximum PSI when it comes to how much power the car will put down... 11psi of maximum boost doesn't do much if you can't flow enough air to maintain it through the powerband, plus you need to keep intake temps down so the car doesn't have to pull timing, and that's all assuming your tune is ideal which is difficult on these cars (between the cam switchover and variable valve timing there's a lot to do on top of the norm).

I'd start by logging spark, AFR, boost, and intake temps and see if anything looks fishy.

 

[addertooth]

I tend to agree with SAN. I only make 7 pounds of boost, but produce 235 Wheel HP. I have both my intake and exhaust optimized as well. Keep in mind, dyno readings vary from one dyno to another.

 

[oldmansan]

OP, you didn't say how much torque you're making. Turbos typically make lots of torque. What are your torque numbers?

San

 

[Giantmcm]

OP, you didn't say how much torque you're making. Turbos typically make lots of torque. What are your torque numbers?

San

2nd this question. Also to point out that the size of your turbo is HUGE and I doubt you are even coming close to putting out the amount of air pressure to even get that thing to do much for your engine. Radium is putting out 360hp on a GT2860RS (according to their page) and 640hp with a GTX3076R.

So based on your turbo size, I am guessing you aren't even coming CLOSE to even getting that turbo to truly start spooling to it's full potential. Which means that you will need to do some SERIOUS engine work to even try and come close to make that turbo move...because I think you just picked a turbo that is JUST TO BIG for the size of the motor you have in that car.

 

[Giantmcm]

Not meaning to hijack the thread but to add to his question: should you always upgrade your clutch when adding a supercharger?

I have had the privilege of running two different types of ACT discs.

The first being the LE1-HDG6 and the 2nd being the LE1-HDSS (currently driving this one now) both on with a Fidanzi lightened flywheel. And when I have to swap out the HDSS I will go back to the HDG6. I liked the disc MUCH better and the ceramic buttons will NEVER wear out. You could launch it hard or you could launch it soft (the key being higher RPMs). To me all in all the clutch acted just like the HDSS but the engagement was always there and there was NEVER a question in my mind in terms of how well it grabs or whether the clutch will slip. I am running N/A power now, and I have had the HDSS slip on me once or twice just the slightest amount and I have also found it harder to slip the HDG6...but that is my 2 cents.

I will state that I have been driving a stick shift since I was 12, currently 35. I haven't found a car with a clutch I haven't been able to drive properly yet...let alone a motorcycle. However I found the HDSS to be one of the hardest clutches for me to use properly...which I find to be pretty ironic.

 

[Westrock]

To me all in all the clutch acted just like the HDSS but the engagement was always there and there was NEVER a question in my mind in terms of how well it grabs or whether the clutch will slip. I am running N/A power now, and I have had the HDSS slip on me once or twice just the slightest amount and I have also found it harder to slip the HDG6...but that is my 2 cents.

The HDSS can be feathered almost exactly the same as the stock clutch. Makes driving in traffic relatively painless. I have been satisfied with the HDSS, but it's all I've tried.

 

[Almighty]

I have Gt35rs turbo, raduim air to air innercooler, custom piping to innercooler. Upgraded clutch, new fuel pump, larger injectors. Alot more to list but not needed for my question. I feel I should make more with those add-ons. Just don't want to buy motor just yet. 12k on the clock now.

There are a lot of questions here. An upgraded clutch means nothing, what is it? "New fuel pump" means nothing, what is it? I can keep going on if you like. Until you can give details on your setup, I still say you should only make 250hp at 11psi of boost.

As someone has already pointed out, the GT35r isn't a small turbo. I've seen 2 liter cars put down 400hp on a conservative tune and mild boost.

 

[holmz]

...

I'd start by logging spark, AFR, boost, and intake temps and see if anything looks fishy.

^Good approach^ - And someone on here can probably find the fishy bits.

 

[GronkDaSlayer]

I have a similar setup.
Smaller turbo I guess but it does about 280rwhp at 18PSI (conservative tune) running on 100 octane. There is also a 10PSI setup that I used most of the time (there is a switch on the front console).

Low compression pistons, .80 head gasket, valves, forged connecting rods, ACT racing clutch, Jubu 3rd and 4th gear. Plus a bunch of other things that aren't relevant to the original question