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To service your opti requires the removal of: the water pump and the harmonic dampner and a few other odds and ends. Although the factory had intended the opt'is to be 100,000 mile units, in reality few will experiece that mileage trouble free and without performance deterioration - so, I think of it as being an item that gets serviced on a more regular interval. Mine was so severely carbon tracked and burned up at ~ 17,000 miles that I put a new cap and rotor in place. You can just clean the inside of the opti if it only has a minor amount of carbon tracking, but because of the work involved most people would be best advised to install a new cap and rotor. My dyno graphs lost their jaggedness once the new cap and rotor was installed - I mentioned the fuel curve because yours is fairly smooth until a little bit below 5,000 rpm.
Wish me luck, I'm an hour away from the start of my dyno day.
:eek: :eek: Isn't that getting up into ZR1/Z06 territory?
Yes, but for peak numbers only. Which in the grand scheme of things does not mean a whole lot. The ZR1's power and TQ curves are very flat. I have not seen a Z06 curve but I assume that it is less peaky as well.
Over the years I've seen anywhere from 300-315 rwhp. The LT4 was under-rated by GM because when the 97 C5 come out it turned out the LS1 wasn't any stronger than an LT4...that presented a marketing challenge for GM with a new model being introduced...later years the LS1 improved it's HP numbers.
Also one must remember that a 20 year old car will lose a bit of it's grunt, so your 300 rwhp is about what I would expect.
Barely broken in. JBRUSS, I'd be satisfied with your numbers.
My stock LT1, which is 24 years old and (more importantly) has ~160k on it, recently put down 280 RWHP...a strong showing and more than it's factory rated, 300 CHP. I wonder how much power it would have made when it was..."younger"?
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Last edited by Tom400CFI; May 3, 2016 at 12:56 AM.
Some of these numbers are questionable in my opinion i.e 330 RWHP that would be close to 400 at the motor. Remember dyno's vary from one to another, the person putting in the data, wheel slip. Lot's of good ready on this subject on the internet. I know I will get flamed by the LT4 guys but I just don't see a "stock" lt4 putting down these numbers unless he was ********ting about the mods, experienced wheel slip on the drum or data input was input incorrectly.
The LT4's get talked about quite a bit. Most think the 330 hp rating was a little low. Most of the dyno tests I have seen tend to support that.
When you compare the engine to an LT1 there were a lot of things changed for only a 30 hp gain. Things like better heads, better intake, better cam, roller rockers should add power and things like a better balancer, better crank, better timing chain, etc add reliability. To me it seems likely that with all the changes there should be more than a 30 hp gain over the LT1. That was a lot of work for GM to only make 30 hp.
I recently got an LT4 and it feels stronger than the LT1's I have had and seems about the same as the LS1's I have had. I have not run mine on a dyno, so I can't say for sure what numbers it really has.
My guess is about 350 hp.
At the Corvette Museum they had the '95 GS prototype. The sign says it is an LT4 350 hp. My guess is that it is the same as what was released in '96.
The LT4's get talked about quite a bit. Most think the 330 hp rating was a little low. Most of the dyno tests I have seen tend to support that.
When you compare the engine to an LT1 there were a lot of things changed for only a 30 hp gain. Things like better heads, better intake, better cam, roller rockers should add power and things like a better balancer, better crank, better timing chain, etc add reliability. To me it seems likely that with all the changes there should be more than a 30 hp gain over the LT1. That was a lot of work for GM to only make 30 hp.
I recently got an LT4 and it feels stronger than the LT1's I have had and seems about the same as the LS1's I have had. I have not run mine on a dyno, so I can't say for sure what numbers it really has.
My guess is about 350 hp.
At the Corvette Museum they had the '95 GS prototype. The sign says it is an LT4 350 hp. My guess is that it is the same as what was released in '96.
This would be the only non-striped Admiral Blue LT4 ever made correct?
I have owned both LT5 and LT4. Both in stock configuration. will run together up to about 100mph than the higher red line of the LT5 will take over. Just for reference my 91 ZR-1 did 326rwhp never had the LT4 on a dyno.
The ZR-1 was never meant to be a quarter mile runner. I also be leave the LT4 has better low end power.
Re: LT4 Dyno Results (rcolling)
